FORTHCOMING IN SYNTHESE

Carnapian Rationality

A.W. Carus

Reason or the ratio of all we have already known, is not the same that it shall be when we know more. — William Blake1

Despite the recent interest in Carnap’s principle of tolerance and its presuppositions, it is still widely

doubted that logical tolerance is compatible with any wider conception of rationality. Post-Quinean

empiricists, among many others, are troubled by the frequent reference to the analytic, the a priori, and

“intuition” in Carnap’s later writings. Others worry that Carnap’s overall view allows only

instrumental rationality, leaving out Wertrationalität (the rationality of ultimate values, as in Max

Weber’s well-known distinction). Any conception of Carnapian rationality would therefore seem to

fall afoul of Hilary Putnam’s well-known critique of “criterial rationality” (e.g. Putnam 1983). From

both these perspectives, Carnapian rationality looks impoverished, incomplete, perhaps just simple-

minded. This paper will argue that, while Carnap did not write down much about his ultimate

conception of rationality, the conception he was heading toward in his later years, once

misunderstandings are set aside, is worthy of attention and perhaps further development.

Section 1 makes these two different kinds of objections to a Carnapian rationality a little more specific.

Section 2 addresses the first kind, showing that, correctly understood, Carnap’s mentions of the a

priori and of intuition in his later writings are entirely consistent with the Carnap otherwise known.

But it may still be thought that, whatever his motivations, no coherent view of rationality can be

developed from such a standpoint; this worry is addressed in section 3. Section 4 focusses on the

second kind of objection, and shows that Carnap took not only the norms of instrumental rationality

but also ultimate values to be subject to rational appraisal — which is not reducible to a list of explicit

criteria. The final section seeks to put the picture of Carnapian rationality arising from these

discussions in a broader context.

1 Quoted by Howard Stein (1998, p. 3). The general perspective developed in this paper owes a great deal to Stein’s writings, not only to those cited, as well as his personal influence as a teacher. I am also grateful to Georg Schiemer for organizing the conference at the Munich Center for Mathematical Philosophy in July 2013 where an earlier version was presented, as well as to Thomas Uebel, Florian Steinberger, and two anonymous referees for perceptive comments that greatly improved the paper.

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1. Two Kinds of Objections to a Carnapian Rationality

In §41F of the Logical Foundations of Probability, Carnap addresses an issue that Feigl had often

raised to him in conversation, and that Russell had recently treated at length in his 1948 book Human

Knowledge: Its Scope and Limits — the question whether all induction rests on the assumption of the

uniformity of nature over time. Carnap agrees that yes, it does, but if we consider it rational to take an

umbrella when rain is forecast, then it is also rational to use induction as a guide to life if the uniformity

of nature is probable, even if not certain. So far so good, but the next step raises hackles. On the one

hand, Carnap admits that the assertion of uniformity (or probable uniformity) is synthetic, and that to

ground inductive inference on it would be circular. On the other hand, he claims his account immune

to any such vicious circle, since his assertion of the uniformity of nature is analytic.

Any statement on probability1 or estimation is, if true, analytic. This holds also for the statements of the probability of uniformity or the estimate of uniformity. . . Since they are not synthetic, no empirical confirmation is required. Thus the earlier difficulty disappears. (1950a, p. 181)

Carnap anticipates the objection that the statement of uniformity has to be taken as factual, since

otherwise an agent X — whose long series of bets in accordance with probability estimates is highly

probable not to result in a loss, thereby justifying action in accordance with probability estimates — will

not be assured of success in the long run.

Our reply is: it is not possible to give X an assurance of success even in the long run, but only the probability of success, as in the statement that [X is unlikely to sustain a loss], and this statement is itself analytic. But can X take a practical decision if he has as a basis merely an analytic statement, one that does not say anything about the world? In fact, X has as a basis for his decision two statements: first a factual statement of his total observational evidence, and second an analytical statement of probability1. The latter does not add anything to the factual content of the first, but it makes explicit an inductive-logical relation between the evidence and the hypothesis in question. (ibid.)

Carnap encountered enough skepticism about this argument that he came back to it repeatedly,2 most

explicitly in the original draft of his autobiography. “I think,” he wrote there, “like most philosophers

today in contrast to those of the last century, that the assumption U [that the world possesses a

sufficient degree of uniformity] is not required; at most the probability of U is presupposed. However,

2 E.g. in his later paper “The Aim of Inductive Logic” (Carnap 1962).

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when we proceed further from this point of common agreement, then my path diverges from that of the

majority of contemporary empiricists. On the basis of the usually accepted frequency conception of

probability, these empiricists interpret the statement of the probability of U as a synthetic statement.”

Whoever accepts the view, as e.g. Russell does, that this synthetic statement is a necessary presupposition, faces the dilemma of either accepting a synthetic presupposition that cannot be confirmed by any inductive procedure, and thus abandoning the principle of empiricism at least in this one point, or [condemning] the whole inductive method and thereby all of empirical science as invalid. In my view the situation is, however, entirely different. On the basis of my conception of inductive logic, the statement that U has a high probability on the basis of the evidence available is interpreted as a statement of logical probability and thus as an analytic statement. Thus the dilemma disappears. Of course it is not possible on the basis of a purely analytic inductive logic to obtain results about the facts of the world. But the decisive point is that in order to recognize the rationality of an inductive method, no factual knowledge about the world is required but only a clarification of concepts. Suppose, for example, that the evidence e says that 100 balls have been drawn from an urn and 99 of them were white and one black, and that the hypothesis h says that the next ball will be black. Then it follows from the meaning of the concept of logical probability that the probability of h with respect to e is smaller than that of non-h. Suppose further that E is the observational knowledge available to the person X at the present time and that the probability of a certain hypothesis H with respect to E is smaller than that of non-H. Then it follows from the meaning of the concept of rationality that it is rational for X to decline a bet at even odds on this prediction H. It seems to me one of the most important philosophical consequences of my concept of induction that it makes it possible to solve the problem of the presuppositions for the application of induction in determining a rational decision, without abandoning the principle of empiricism. (UCLA Box 2, CM3, folder M-A5, pp. P20-P22)3

Since Quine, of course, many philosophers have taken exception to the idea that anything is explained

by classifying a sentence as “analytic.” While this passage does not explicitly use the terminology of “a

priori,” Carnap’s rhetoric seems to imply that the mere classification of a sentence as “analytic” is

sufficient to give it some explanatory force.4 Those like Putnam (e.g. 1983), on the other hand, who

reject all “criterial rationality”, cannot countenance “the meaning of the concept of rationality,” or

accept that any meaning one might agree on could by itself establish that “it is rational for X to decline

a bet at even odds on this prediction H.” Again, Carnap’s rhetoric appears to imply something that is

not fully spelled out, in this case that there is a single unquestioned concept of rationality for which

explicit criteria can be stated, and — since such criteria must be internal (in the sense of Carnap

1950b) — that this unambiguous meaning cannot extend beyond instrumental reason.

3 This passage, originally in section 12 of Carnap’s (1963) autobiography, was omitted from the published version. 4 Of course one might accept Carnapian accounts of both “analytic” and “a priori” and still reject Carnap’s argument here, e.g. because one rejects his conception of probability. This is bracketed here; Carnap’s conception of probability and induction is used in this paper only to illuminate his larger conception of rationality, and nothing depends on it.

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These two kinds of objections are by no means exhaustive, but they cover a wide range of possible

critiques, and come from opposite ends of the spectrum, in a sense; while they do not contradict each

other directly, it seems that if one of them is right, the other must be wrong. This paper will argue they

are both wrong, as they both misinterpret Carnap’s admittedly often clumsy rhetoric, and his way of

framing these issues in his later years.

2. First Complaint: A Priori Intuitions

One thing that has made people particularly uneasy about the later Carnap’s invocation of the

“analytic” or the “a priori” is that it often occurs in conjunction with the notion of “intuition.” Here is

an example from the Schilpp volume that has been singled out for such criticism:

It seems to me that the reasons to be given for accepting any axiom of inductive logic have the following characteristic features. . .: (a) The reasons are based upon our intuitive judgements concerning inductive validity, i.e., concerning inductive rationality of practical decisions (e.g. about bets). Therefore: (b) It is impossible to give a purely deductive justification of induction. (c) The reasons are a priori. (Carnap 1963, p. 978)

And Carnap’s last major talk, at Popper’s London conference in 1965, was about “Inductive

Intuition” (much to Popper’s dismay), which continues to arouse consternation. John Earman, for

instance, is willing in principle to consider Carnap’s goal of making “the constraints of rationality

extend beyond the requirements of coherence, which entails that degrees of belief must conform to the

standard axioms of probability. According to Carnap the requirements of rationality do not suffice to

single out a unique probability function, but they do significantly constrain the choice of a probability

function . . .” (Earman 1993, pp. 28-9) Carnap’s attempt fails, though, in Earman’s view:

However, I do not think that Carnap managed to stake out a defensible position, as can be brought out by the question of how one recognizes which probability functions are “rational.” Carnap’s answer was to appeal to what he variously called “inductive intuition” and “inductive common sense.” The trouble, of course, is that one person’s inductive common sense is another person’s inductive non-sense. So the appeal to intuition reveals very different

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opinions as to whether it is rational to learn from experience at all and, if so, at what rate. (ibid., p. 29)

I will argue, against this view, that perfectly good sense can be made of these uses of “a priori” and

“intuition,” even to John Earman. The above passage from the Schilpp volume is followed immediately

by some further clarification:

By (c) I mean that the reasons are independent both of universal synthetic principles about the world, e.g. the principle of the uniformity of the world, and of specific past experiences, e.g. the success of bets which were based on the proposed axioms. If e represents the total experience of X so far, then the value of c(h,e) is certainly dependent on e, and thus upon the experiences of X. However, the acceptability of the axioms, by which the value of c(h,e) is determined or by which certain restrictions are placed on admissible c-functions, is independent of these experiences. (Carnap 1963, p. 979)

This represents a change of mind from a view Carnap had held only a few years previously, e.g. in §18

of the Continuum of Inductive Methods:

It is psychologically difficult to change a faith supported by strong emotional factors (e.g. a religious or political creed). The adoption of an inductive method is neither an expression of belief nor an act of faith, though either or both may come in as motivating factors. An inductive method is rather an instrument for the task of constructing a picture of the world on the basis of observational data and especially of forming expectations of future events as a guidance for practical conduct. X may change this instrument just as he changes a saw or an automobile, and for similar reasons. If X, after using his car for some time, is no longer satisfied with it, he will consider taking another one, provided that he finds one that seems to him preferable. . . (Carnap 1952, p. 55)

This earlier view puts everything at the same level; the tools we use to choose tools are chosen in the

same way and with the same tools that we use for object-level choices among goods or bets. This is

essentially the attitude familiar from the Logical Syntax, where “usefulness” or “convenience” became

the only criteria for the choice of language.

Further reflection clearly made Carnap uncomfortable with this assimilation, since by 1957, when he

wrote the above passages from the Schilpp volume, he was saying that, while this one-level approach

was not downright wrong, it could be dispensed with. Rationality, he now began to think, should not

actually need to use experience to decide on the tools for learning from experience. Decisions about

rationality should be taken at a different level from the everyday decisions that use and presuppose

rationality. Inductive logic was no different from deductive logic in this respect; it was a different

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aspect of rationality, but no less a priori. Of course, as Carnap stresses in the further elaboration of the

above passage from the Schilpp volume, he does not mean synthetic a priori, and the principle of

tolerance continues to govern the choice among “a priori” tools. But the considerations by which we

shape the basic components of our rationality should not be at the same level as the choices made by

means of our reason, once constructed. They should be more principled and structural than mere

iterated learning from empirical error; they need not be “blind,” but can be informed by what we know.

But what does “intuition” have to do with it? That would seem — has seemed, to Popper, Earman, and

many others — to go in precisely the opposite direction, away from anything more principled and

structural than mere learning from error. But here again, we need to look more closely at what Carnap

was actually saying, specifically in response to his sustained immersion in the probability literature

from the early 1940s. As long as he had focussed largely on deductive logic, the pragmatics of

notation systems did not overly concern him. One could try out different logics and not worry too

much about the motivations underlying this or that axiom system. But inductive logic was different; the

justifications of various axioms were much more concretely rooted in scenarios of practical rationality,

human gain and loss. The Dutch Book arguments underlying the Ramsay-De Finetti representation of

coherence on the basis of the axioms of probability, for instance, obviously rely on intuitions about the

structure of certain bets and the advisability of taking them; “the question of the validity of inductive

reasoning goes back to — or, at least, can usefully be based on — considerations about the rationality of

decisions.” (Carnap 1968, p. 264)

But this does not make the “rationality of decisions” any less a matter of logic for Carnap. This is easy

to misunderstand. With respect to the distinction between deductive reasoning (a priori, analytic),

and what is usually called inductive or experiential reasoning (a posteriori, synthetic), we expect

inductive reasoning to fall on the experiential side. This is not how Carnap saw it; for him, all

reasoning, all of what he thinks of as “rationality,” falls on the a priori and analytic side, including both

inductive and deductive reasoning (e.g. Carnap 1950a, §§41-45, esp. §43B).

Decisions about the basic structure of our rationality are, of course, based on “relativized” a priori

considerations, as Michael Friedman would say. In fact, they are voluntaristic a priori; we decide on

them. But how? If we are not to use experience, if we are not to think of them as tools at the same level

as all the other tools we employ, then how are we supposed to proceed? Well, the suggestion is not that

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we ignore experience, but that we use it “heuristically”;5 experience is unable (by itself) to decide (as it

decides questions with empirical content). We can, after all, foresee possible paths of experience,

which means that we can incorporate our response to those paths into a more general method, which

would thus obviously be more robust and flexible. Carnap gives a (still not very concrete) example in

an unpublished paper of 1957:

At the time t0, before X had the actual sequence of experiences, say e2, which induced him at the time t1 to change from cA1 to cA2, he might have considered the possible sequences e1, e2, e3, etc. for the period from t0 to t1 and reasoned as follows: “I shall re-examine my method cA1 at time t1 in view of the experiences made up to that time. If the experience sequence e1 occurs, I shall find that the method cA1 had been more successful than any other of the methods cA, and I shall therefore decide to continue using it. If, however, e2 occurs, I shall see that cA2 would have been more successful than cA1, and therefore I shall change over to cA2. If e3 occurs, I shall instead change to cA3, etc. Since now, at t0, I can foresee these hypothetical changes to be made at t1, it seems preferable not to begin with cA1 or any other method of the class cA, but instead to use a more general method, say cB, which incorporates the desired influence of the experiences up to t1, whatever they will be, into its rules. Then, for any h, the value of cB(h, e1) will be similar to that of cA1(h, e1), likewise cB(h, e2) similar to cA2(h, e2), etc.” This example illustrates the following point: although it is not wrong to abandon an inductive method and choose instead another one in view of past experiences, this procedure does not seem necessary. It should in principle be possible to construct a generalized method and thereby avoid changing methods in view of previous experiences. And if we succeed in doing so, such a method would be preferable. (ASP/RC 082-07-01, p. 11)

This suggests two things. First, experience is not left out; Carnap’s point is not that only a priori

considerations are relevant to the decision, it is that experience by itself does not determine the

decision. Obviously without a store of experience (and a science based on it) there would be no way to

describe the possible paths e1, e2, e3, . . .

Second, this passage suggests that a different kind of “experience” does actually influence our

reasoning, deductive as well as inductive, which is our cumulative experience, as a community of

reasoners, of working with our formal instruments — our experience with the “a priori.” Carnap often

comes back to this:

For fruitful work in a field it is not necessary to be in possession of a well-founded epistemological theory about the sources of knowledge in the field. Both arithmetic and geometry were successfully developed for more than two thousand years before the first detailed epistemological theories for both were offered by Kant; and althought some important insights have since been gained, there is even today no complete agreement. On the other

5 As Carnap puts it in the unpublished typescript discussed further down in this paragraph (ASP/RC 082-07-01, p. 10).

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hand, it is certainly helpful, also for work on substantive problems within a new field, if we can achieve even a little, more explicit awareness of what we are doing and how new knowledge in the field is gained. When we face a difficult problem, this insight may help us to see in which way and in which direction we should look for a possible solution. Thus our working procedure, which in the beginning is inevitably more or less instinctive, may slowly become more consciously directed. (Carnap 1968, pp. 266-7)

This suggests that what Carnap meant by the “inductive intuition” (and “deductive intuition”) that has

so confused people is the instinct referred to here, developed over generations of instrument-users

gaining experience with it. The “intuition” here is just the embedded and encoded first-hand

experience of the formal-instrument-user community.6 Those who have not been socialized into the

use of these instruments will not share these intuitions; nothing would have surprised Carnap less than

the Tversky and Kahnemann research about preference reversals and other “mistakes” untrained

humans are prone to when faced with questions of probability.7

“Intuition,” then, is just a source (perhaps the main source) of explicanda. Spelling out intuitions of

the formal-language user community, making them explicit, arriving at provisional agreement on them,

and finding room for them in existing formal systems, are essential parts of the explication process;

they constitute the crucial step of “clarification of the explicandum” (Carnap 1950a, §2).

3. First Complaint Reasserted: A Priori Presuppositions

The first kind of critic will now perhaps admit that Carnap’s heart was in the right place. But can his

strategy actually be made to work? Or is the aspiring Carnapian forced, despite these good intentions,

to rely on unacknowledged “a priori” presuppositions in a more substantive sense like Kant’s? This

was just what a number of 1950s commentators on Carnap’s inductive logic argued, and it was 6 Where the emphasis is on “first-hand” — the relevant intuitions are those of active users, not passive commentators or consumers. Carnap suggests this in his reply to Ernest Nagel when he says that Nagel’s intuitions would change if he actually tried to construct a logic of confirmation himself: “. . . since the time I began to construct a system of inductive logic, I myself had sometimes to change intuitive judgments on certain properties of logical probability. And this occurs still today when I begin to think about the extension of inductive logic to a new, more complex language form. If Nagel were to try to construct a system of [degree of confirmation] on the basis of his present intuitive judgments, I am convinced that he would change quite a number of these judgments because he would find that the system would yield many results which would appear to him either as undesirable or even as entirely unacceptable. From experiences with my own intuitive judgments and those of friends whom I often asked for reactions to particular results, I have learned that isolated intuitive judgments are often very unreliable. Of course, the development of inductive logic must be guided by intuitive inductive judgments. But these judgements are more useful if they are made, not on isolated points, but in the context of the tentative construction of a system.” (Carnap 1963, p. 994) 7 Any more than he was the least fazed by Arne Naess’s research showing that half the population did not use the truth predicate in accordance with Tarski.

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evidently in response to these that Carnap’s view had changed as described in section 2. When the

Princeton philosopher John Lenz published a critique to this effect in Philosophy of Science in 1956,

Feigl (who had evidently been urging the point to Carnap in conversation since 1942)8 wrote to

Carnap that Lenz

. . . raises (without reference to Burks or to my “Scientific Method without Metaphysical Presuppositions”)9 exactly (and more explicitly) the questions I’ve tried to put to you for many years. Maybe he and I are stupid or confused — but I think the questions are serious and important. Of course, he doesn’t answer them — and my answer may not be good enough. But do let us have your answer! (ASP/RC 089-57-02, Letter of Feigl to Carnap of 3 August 1956)

Carnap felt obliged to comply, and wrote several drafts of a response to Lenz over the next year or two,

which remained unpublished. The first draft was a restatement of the previous position laid out in the

above quotation from Continuum of Inductive Methods. Only when Hempel pointed out that Carnap

appeared not really to be addressing Lenz’s critique head-on10 did Carnap start over, and begin to

revise his view as he revised the paper. The result was a new draft “How Can Induction be Justified?”

in which he distances himself explicitly from the position, quoted above, that he had taken in

Continuum of Inductive Methods. Also, he now sharply distinguishes between two steps — the choice

of axioms for inductive logic and the choice of a particular method within the λ-class defined by the

chosen axioms. Different standards apply to these two steps. The choice of axioms, he argues, can (or

should) make use only of deductive and inductive reasoning, not of experience and not (obviously) of a

synthetic a priori principle. The second step (the choice of method) can also make use of experience

(in addition to deductive and inductive reasoning), but need not; this is where Carnap distances

himself from §18 of Continuum of Inductive Methods) and argues (section 2 above) that various

possible paths of experience can be anticipated without actual trial and error.

8 Though Carnap may well have written the section on uniformity of nature (§41F, quoted above, section 1) in 1949, as he says in the original draft of his autobiography, the discussions with Feigl go back to at least April 1942, i.e. before he wrote the rest of the book; a diary entry says “Mit Feigl ausführlich über dc [degree of confirmation]. (Er: darin steckt immer faktische Annahme über Gleichförmigkeit der Natur.)” (ASP/RC 025-82-08, 26 Apr 1942) Carnap also made several notes on uniformity of nature at around this time, mentioning Feigl’s question about what factual assumptions underlie Carnap’s proposed degree of confirmation (ASP/RC, folder 078-25). So the fact that Carnap wrote section 41F later likely meant that he was not yet satisfied he had worked out this problem to his own satisfaction by 1944-6. 9 Feigl presumably has in mind Burks (1953) and Feigl (1954). 10 Hempel makes specific reference to the passage from §18 of Continuum of Inductive Methods quoted above, and asks whether “while the choice of a c-function, to be sure, need not rest on any empirical assumption, the problem remains whether the justification of such a choice as adequate would require reference to empirical fact. . . I wonder whether you could not add a word about that question, because otherwise the reader might feel that your reply sidesteps a crucial issue at stake.” (ASP/RC 089-57-03, p. 2)

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Lenz claimed that Carnap’s use of the uniformity of nature was circular in just the way that Carnap had

denied in the quotation we began with (from Carnap 1950a, §41F). For present purposes, we are

concerned not with the uniformity of nature or with inductive logic, but only with Carnap’s view of

rationality as revealed by his argument. So with that focus in mind, just two points in Carnap’s

response to Lenz will be singled out.

First, Carnap denies the circularity on the grounds of his two-step procedure in justifying an inductive

method. If we have first established a λ-class by choosing axioms, then for purposes of choosing a

method within that class, those axioms can be regarded as provisionally fixed. Assuming that the

axioms apply equally to all the methods under review, there is nothing circular about using the axioms

in justifying the choice of method c over method c'. Among the justifiable axioms, Carnap says, is the

axiom of instantial relevance, or as he puts it here, “the axiom of learning from experience,” which he

paraphrases as “If one of two properties (of the same logical form) has occurred more frequently than

the other among the observed cases, then, other things being equal, its occurrence in the next case is

more probable than that of the other property.”

Lenz is, of course, right that it would be illegitimate to try to justify the preference of c to c' by inductive reasoning based specifically on c. But the use of the axioms is legitimate because they are satisfied by both c and c'. Now suppose that the evidence available to X shows that with respect to the observed cases c was more successful than c'. Then it follows from the axiom [of instantial relevance] that it is more probable than not, other things being equal, that in the next case, or in any class of future cases, c will be more successful than c'. (ASP/RC 082-07-01, p. 18)

Carnap concludes that “it is possible to make an inductive inference, i.e. a comparative probability

determination, for the future successfulness of two methods c and c'; the result may then be a factor in

the justification of the preference of c over c' and thus of the choice of c.” He further concludes “that

this inductive inference does not make use of c and thus does not involve a vicious circle; and further it

does not use any synthetic assumption concerning the future.” (ibid., p. 19)

The new preference, discussed in the previous section, for a more “principled” way of arriving at

axioms of inductive logic than blind trial and error, amounts then, to a hierarchical form of reasoning,

corresponding to the “levels” at which different choices are made. Since the choice of axioms for

inductive and deductive logic were fundamental to rationality, they were necessarily prerequisite to the

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choice of an inductive method within the bounds permitted by that choice of axioms. So for the

purposes of the latter choice, the axioms may be held constant.

This illustrates vividly the second point in the above argument from 1957 to be highlighted here (as

exemplifying Carnap’s view of rationality): in terms of his (1950b) distinction between “internal” and

“external” questions, this argument reveals that the justification of constitutive axioms — of inductive

no less than deductive logic — is an external matter. Arthur Burks (1963) pointed this out long ago,

and Carnap not only confirmed that Burks was right, but also reaffirmed that these external questions

were to be understood as practical ones. Moreover, he adds,

. . . first, that it is an important task of the philosophical clarification of induction to specify the factors which are relevant for a rational decision of a practical external question; and, second, that important theoretical questions are involved in the relevant deliberations leading to a practical decision of this kind. (Carnap 1963, p. 982)

So while it may well appear, if we look only at Carnap’s work on inductive logic, that his concern is

exclusively with a rather narrow conception of instrumental rationality, we now see that Carnap

regarded the norms of instrumental rationality to be subject to rational appraisal — in which he

specifically included theoretical considerations. This discussion of Carnap’s reliance on the a priori

leads naturally, then, into a discussion of the other, opposite, objection of the two considered in

section 1 — the objection that only Zweckrationalität could fall within Carnap’s purview, to the

exclusion of Wertrationalität.

4. Second Complaint: Instrumental Rationality

The suspicion that Carnap can entertain only instrumental rationality is widespread.11 This suspicion

usually takes one of two forms. In the context of the Carnap-Quine debate it takes the form of a kind of

category-mistake diagnosis. Carnap’s conception of reason, it is held, requires any assertion to be

relative to a linguistic framework. Therefore there can be no rational assertion, no “judgement,”

11 Since Carnap is an emotivist, according to one such critic, “value statements lack cognitive content; they do not have any truth-value. But then the justification of science on the basis of ethics is not really a justification at all since the claim about the good life merely expresses Carnap’s emotive state or disposition toward life.” So “emotivism in ethics severed the crucial link between science and the good life as he envisioned it. Perhaps this is the ultimate aporia of logical empiricism.” (Irzik 2003, pp. 343-4)

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outside any linguistic framework,12 e.g. bearing on the choice among frameworks. The choice among

frameworks (and thus also — more locally — the choice among explications for a particular

explicandum) must therefore take place outside any rational framework.13 So for Carnap, rationality

can only be instrumental, the story goes, since any form of meta-rationality, outside a specified

framework, is by definition not part of rationality.

Another form of this same suspicion is to discern an infinite regress in Carnap’s view that the choice

among linguistic frameworks, or explications, cannot be made within one of the frameworks to be

chosen among. It must be, according to Carnap, external to any of those frameworks. But this, it

seems (Steinberger 2014), leaves Carnap with two choices: either the choice among frameworks is

arbitrary and irrational or there must be a rational “selection framework” in the metalanguage in which

the choice among object-level frameworks is made. But which framework? How can we make a choice

among meta-frameworks without invoking a selection framework at the meta-meta-level, and so on?

Where does this regress stop? And if we cut it off at some level, we again leave Carnap with only

framework-internal, i.e. instrumental, rationality.

A different perspective on this problem was introduced by Howard Stein (1992), who saw that in the

later Carnap, the relation between the theoretical and practical was implicitly dialectical. There is an

interplay or mutual feedback relation, in this view, between formal media of reasoning, on the one

hand, and the realm of practical decisions — the values by which we choose or decide among candidate

explications or languages — on the other. The knowledge we articulate in our formal languages

constrains the decision space of possible actions (including verbal actions such as explication), it

informs us of the consequences of various choices within that space, and shapes our values in many

other respects. But on the other hand, our values (which, though shaped, informed, and constrained in

many ways by this knowledge, are not determined by it) in turn guide our choices among explications 12 This widespread view projects a Wittgensteinian absolutism regarding the “boundaries” of language onto Carnap, who explicitly rejected it and endorsed a gradualist conception, e.g. in Carnap (1963, p. 934). 13 One of the clearest statements of the tradeoffs between such a position, attributed to Carnap, and a Quinean position where we are simply inside whatever framework we are in, in mediis rebus (Dreben 1994), without access to its basic framework principles, let alone the ability to choose them, is that of Alexander George (2012), concluding: “But for Carnap, as we have seen, such considerations can at best exert a non-rational influence on an agent who is choosing which framework to adopt. Talk of rational constraint only has its place within a framework, once a language and rules of reasoning and inquiry have been settled upon. For Carnap, this observation is critical in understanding why traditional philosophical disputes have proven to be so frustratingly irresolvable and so different from scientific disagreements: philosophers, unlike scientists, typically dispute about which framework to adopt, which language to speak, and no facts about the world can rationally bear on such disagreements. The empirical facts only come into focus, and talk of rational relevance only gets a grip, once a particular linguistic framework has been adopted.” (George 2012, p. 10)

— 13 —

and formal languages, and thereby also shape our knowledge by determining what we mean by

“knowledge.” So there is a continuous mutual feedback: values ultimately determine what we define as

reason, but the reason thus provisionally defined informs and enlightens our values; reason is not the

slave of the passions, as in Hume, but nor can reason determine our values, as in Kant.14

This is not an empirical claim about how the practical and theoretical realms ordinarily interact, but a

regulative or ideal portrayal of how they could interact (and have sometimes interacted) to optimize the

beneficial consequences of human knowledge to the species. In this regulative ideal, our ultimate

values are not dogmatically fixed, but open to correction by what we as a species have progressively

come to learn about the world we inhabit (including ourselves). This ideal portrayal is essentially that

of the Enlightenment, in which knowledge self-consciously arrived at by empirical criticism of

hypotheses programatically replaces passive acceptance of traditional and folk knowledge as the basis

for individual and collective action (Carus 2007, Ch. 1 and 11).15

But in the traditional Enlightenment view of the eighteenth and nineteenth centuries, even of the

Vienna Circle in its heyday, the new knowledge replacing traditional and folk knowledge was

authoritative; it was the final word, even if in some accounts it was portrayed as permanently evolving,

never entirely finished — scientific knowledge was still the ultimate tribunal. This cognitive

authoritarianism made the Enlightenment vulnerable to criticism from the start.16 Carnap, however,

suggested a way of overcoming it. In the Carnap-Stein view described above, scientific knowledge

becomes framework-relative (and thus, in a certain dimension, value-relative). Moreover, if the

framework permits such a virtuous dialectic, there will be a continuous mutual adjustment between

provisionally-chosen principles of rationality and the knowledge we arrive at within the framework

defined by those principles. And if we regard these principles of rationality as a hierarchy of the kind

we observed in section 3 within the principles of inductive logic, then the highest level of this hierarchy

includes principles of practical reason articulating ultimate values. There is no infinite regress of

selection frameworks since these ultimate values, just as in a Kantian context, determine choices of

14 Cf. the discussion of Stein’s conception of pragmatics more generally in Carus (2010). 15 Which is again not to claim that the non-traditional, non-conformist origins of knowledge or values make them inherently “better,” certainly not by any absolute standard, though presumably there is a better chance for knowledge generated within the constraints of a given value system to be “better” by the standards of that value system. 16 Among the better-known milestones in this tradition of Enlightenment critique are the Romantic (and Goethean) rebellion against the portrayal of nature in terms of “Zahlen und Figuren,” Adorno’s and Horkheimer’s “dialectic of enlightenment,” and Richard Rorty’s rejection of science as a cognitive exemplar (Carus 2007, Ch. 1).

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frameworks and explications, even as they continuously adjust to the better knowledge framed in terms

of those frameworks.

This view may perhaps be found attractive, and perhaps even consistent with Carnap’s late perspective,

but did the actual Carnap hold anything like it? Some of his 1930s rhetoric about value statements

“having no meaning,” and his caginess about the nature of the choice among frameworks or

explications (George 2012, pp. 5-6), suggest a negative answer. But there is also considerable

evidence that Carnap did in fact maintain a dialectical view of the kind suggested by Stein regarding the

interrelation of knowledge and values (Carus 2007). And surprisingly, it turns out there is even

evidence that Carnap held ultimate values to be subject to rational considerations. This is made

explicit in a shorthand fragment in Carnap’s Nachlass on “value statements” that Carnap had originally

sketched as part of the final section of his replies in the Schilpp volume (ASP/RC 089-14-01). He

evidently decided that this reply, however, already by far the longest in a thousand-page book, was

getting out of hand, and saved up this part for a separate publication (which he never got around to).

In this fragment, Carnap first discusses rationality relatively to a value function, which is a function of

an entire world history (state description with arbitrarily long time dimension). “Good,” “better,” and

other value words are defined relatively to such value functions. A person has many different value

functions of different scope, ranging from those focussed on a particular value aspect, such as health or

good food, to the most comprehensive value function in which all aspects are weighted according to

their relative priority within an overall system of values. These comprehensive value functions, Carnap

says, might appropriately be called the moral ones. The narrow-scope value functions are essentially

expected utility functions restricted to a particular decision problem as addressed in decision theory;

the “possible worlds” or “states of nature” that frame the decision problem are restricted to a limited

number of parameters (e.g. whether it is raining or not, what to eat), and the expected utility function

ranges over a limited number of arguments (staying dry, good health, pleasure in eating).

Confirmational success is one example of a narrow-scope value; the expected utility function in an

inductive decision problem ranges over arguments such as fidelity to the facts or empirical robustness.

Carnap notes that in the case of induction (as correspondingly in other narrow-scope decision

problems) it is customary to suppose that certain inductive methods or axioms could be criticized as

irrational, by a priori standards of inductive rationality (“a priori” understood as in section 2 above).

— 15 —

He then asks whether it makes sense to suppose that there could analogously be standards of

rationality for (comprehensive) value functions themselves. And he argues that yes, in fact, we can

impose standards of rationality on moral value functions. He makes some rather throwaway

suggestions for the kind of thing he has in mind, involving formal constraints on the shape of the value

function (e.g. that it not fluctuate too drastically over time),17 but backs off immediately and says he has

nothing invested in these examples, and is adducing them just as illustrations.

In any case, wherever he might ultimately have taken this, it is worth emphasizing that he was not only

willing to entertain a broader instrumental rationality, as in the replies to Lenz and Burks cited in

section 3, but far beyond that, argues here for the rationality of ends. An echo of Kant — especially the

hierarchy of Vernunft and Verstand — is unmistakable. For Carnap says, strikingly, that “all logic,

including inductive logic, and factual knowledge are irrelevant” to the question of the rationality of

(comprehensive) value functions; we must rather draw on “other, purely valuational criteria by which

to judge a value function as more or less rational than another.” (ibid., p. 4) So comprehensive value

functions are not only a component of rationality; they govern the choice of instrumental values

(narrow-scope or partial value functions) that constitute the reason by which we judge axioms of

deductive and inductive logic — they govern the application of the understanding to its objects. The

understanding, asymmetrically, has no bearing on the principles of reason.

It is clear that this sweeping exclusion cannot be taken quite literally; in his examples of possible

“purely valuational” constraints on comprehensive value functions, Carnap uses both empirical

concepts and concepts of analysis such as continuity and differentiability. Indeed, it is hard to imagine

how “all logic and factual knowledge” could be avoided in the specification of such constraints. As in

the case of the choice of inductive axioms and inductive methods, Carnap obviously does not mean that

experience has no relevance whatever to the choice of values. He evidently means, as in the inductive

case, that it cannot determine the choice of values. Experience, i.e. empirical knowledge (called

“descriptive pragmatics” in this context), forms the essential background to all deliberation about

values, (Carnap1963, p. 83), just as it does in deliberation about inductive axioms and explication

17 These examples suggest that he would have liked the general approach, at least, of Nozick’s list of 23 — progressively stronger — conditions for constraining “rational” utility functions in the section “Rational Preferences” of a chapter entitled “Instrumental Rationality and its Limits” (Nozick 1993, pp. 139-151). Nozick does not argue explicitly that there is no genuine distinction between instrumental and substantive rationality, but by the end of this list it is hard to deny that the boundary is much less clear-cut than the rhetoric surrounding this debate usually suggests.

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more generally. Its role in the pragmatic sphere is not determinative, though, it is (as he says in the

unpublished 1957 paper quoted from in sections 2 and 3) “heuristic” (footnote 5 above).

And as in our discussion in section 3 of Carnap’s hierarchical justification of the axioms of inductive

logic — holding them fixed for the purposes of justifying the choice of a particular inductive method

within a λ-class — it seems clear that the principles of a given comprehensive value function, once

decided on, are also to be held provisionally fixed as a basis for choices of axioms for inductive logic,

deductive logic, and other components of our “rationality.” In other words, the hierarchy of rationality

has at least three levels, in the case of inductive logic, and could in other cases have more.

While such a hierarchy of reason and understanding, and the primacy of practical reason, are certainly

reminiscent of Kant, the resulting perspective can hardly be called Kantian in any substantial sense. It

lacks the keystone of Kant’s normative structure — a “supreme principle of morality.” Practical reason

is allowed for in Carnap’s view, but imposes insufficient constraints to generate any such positive

principle.18 And the Carnap-Stein regulative ideal described above, where reason and understanding

mutually inform each other in a virtuous dialectic, is more that of the western Enlightenment, of

Diderot, Hume, or Condorcet, than of Kant, who stressed the complete independence of practical

reason from the understanding.

But if Carnapian practical reason can generate no supreme principle of morality, if it can only

constrain, not determine, the choice among frameworks, how can it decide on the cognitive framework

to be employed for science? How can it stop the infinite regress of framework choices? Well, how is

the regress stopped in other practical decisions? For Carnap, this question has two components, since

action-guiding normative sentences, in his view, have not only a normative component (the province of

pragmatics), but also a cognitive (or descriptive) one (belonging to semantics). The cognitive

framework for decision-making does generate a potentially infinite hierarchy of meta-languages, but in

practice our ultimate meta-language is a form of the “mother tongue,” as Quine called it.19 There is a

fundamental difference, though, in the status of this retreat to ordinary language in Carnap and Quine,

18 Allen Wood (2006) portrays Kant as rejecting the idea that there could be fundamentally different “supreme principles of morality,” and as arguing that practical reason shows all such supreme principles to be equivalent. This would make Carnap’s loose and pluralistic practical reason even more un-Kantian than suggested above. 19 In precisely this context of a threatening regress of languages in which to specify quantifiers of object languages lower in the hierarchy: “. . . in practice, we end the regress of background languages, in discussions of reference, by acquiescing in our mother tongue and taking its words at face value.” (Quine 1969, p. 9)

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reflecting their differing appraisals of the availability of an external perspective.20 For Quine the

recourse to the mother tongue is a kind of acquiescence in a default standpoint that we take “at face

value,”21 while for Carnap the ordinary language in which we make practical decisions, including the

decisions about which language to use for what, is precisely not to be taken “at face value,” but rather

as a rough and ready Neurathian “universal vernacular”22 in which all the concepts that have scientific

explications are to be taken in their explicated senses. In the Syntax, it is true, Carnap had aspired, as

he himself testifies (Carnap 1963, p. 55) to make the philosophical metalanguage completely precise.

But he later gave up this ideal; indeed he admitted that “even when I proposed them” none of his

explications of the term “philosophy” — and thus of the pragmatic meta-language — “seemed fully

satisfactory to me . . . and I did not like the explications proposed by others any better. Finally, I gave

up the search.” (Carnap 1963, p. 862) So while there is indeed a sense in which both Carnap and

Quine accepted a version of the “mother tongue” as the practically necessary ultimate metalanguage,

there remains the fundamental difference that Quine took his version of the “mother tongue” at face

value and insisted that truth is truth and reality is reality (Dreben 1990, p. 85), while Carnap saw no

reason for accepting such traditional terms at face value. They occur in the scientific vernacular we

have to use in ordinary communication, but are to be understood only in their explicated senses —

which dispense with “ontological commitment” along with many other folk notions embedded in

ordinary language.

20 Ricketts (2004) disagrees, citing Carnap’s reply to Evert Beth: “Since the metalanguage ML serves as a means of communication between author and reader or among the participants in a discussion, I always presupposed, both in syntax and in semantics, that a fixed interpretation of ML, which is shared by all participants, is given.” (Carnap 1963, p. 929) But Carnap himself, in the same text, makes explicit that he does not intend this shared default language to be taken at face value. “It seems to be obvious that , if two men wish to find out whether or not their views on certain objects agree, they must first of all use a common language to make sure that they are talking about the same objects. . . It is of course not quite possible to use the ordinary language with a perfectly fixed interpretation, because of the inevitable vagueness and ambiguity of ordinary words. Nevertheless it is possible at least to approximate a fixed interpretation to a certain extent, e.g. by a suitable choice of less vague words and suitable paraphrases.” (ibid., pp. 929-30) 21 Though a very different one from that held out by the ordinary language philosophers, who considered ordinary language the philosopher’s “sole and essential point of contact with reality.” (Strawson 1963, p. 518). For Quine, the status of ordinary language is much more problematic, since it has no independent authority (the parts of it found defective, within the conceptual scheme as a whole — in the light of regimentation — are to be eliminated), but is nonetheless a kind of default standpoint. 22 Here again, as in the case of Stein’s extrapolation from Carnap above, some interpretive leeway is required that some readers may find too wide, and reject as incompatible with their conception of Carnap’s overall perspective. In this case, the leeway in question is that suggested by Thomas Uebel (2007, p. xvi) regarding what he sees as the “emerging consensus on metaphilosophical matters on the so-called left wing of the Vienna Circle,” which includes not only Carnap and Neurath but also Philipp Frank and Hans Hahn, among others; see also Uebel (2004), and further discussion on the “scientific vernacular” in Carus (2007, Ch. 11).

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What about the normative component of our decision-making framework? Does an infinite regress

threaten here? In addition to first-order preferences, people have preferences about those

preferences, and so on.23 But this hierarchy, like the semantic one, is limited by human processing

capacity, and in effect people mostly have stable long-term preferences that function as comprehensive

value functions of the kind Carnap sketches, corresponding to the longer-term preferences he takes

for granted in his writings on inductive logic.24 It is in the light of this comprehensive function,

trading off short-term needs and desires against longer-term values, that people make the actual

choices constituting their “revealed preferences.”

These still do not determine the choice of framework, since a framework, or even a particular

explication, is not chosen by an isolated individual, but by a social process of some kind. Individual

choices translate into social choices via economic, social, and political interactions. The pluralism of

this Carnapian open-ended form of practical reason is fundamental, then, reflecting that the choice of

frameworks for knowledge cannot be decided by impersonal reason alone but is — as in John Stuart

Mill — a matter for (reason-guided) controversial, political interaction.

In fact, the Carnap-Stein regulative ideal described above can also be seen as nudging individual value-

functions toward a degree of convergence, at least within the subset of values that concern the

framework for social and political interaction (“framework values”).25 For insofar as individual value

functions incorporate this regulative ideal, they will be framed within the same “scientific vernacular,”

and thus be influenced by roughly the same empirical facts and theories.26

23 Frankfurt (1971) introduced this idea into the moral philosophy literature, where it has been current ever since, but never high profile, any more than in economics, despite the occasional efforts of Amartya Sen. 24 For instance, in Carnap (1962, p. 312): “In the sphere of human action we have first concepts describing overt behavior, say of a boy who is offered the choice of an apple or an ice cream cone and takes the latter; then we introduce the concept of an underlying momentary inclination, in this case the momentary preference of ice cream over apple; and finally we form the abstract concept of an underlying permanent disposition, in our example the general utility function of the boy. . . When we wish to judge the morality of a person, we do not simply look at some of his acts, we study rather his character, the system of his moral values, which is part of his utility function. Single acts without knowledge of motives give little basis for a judgment. . .” 25 On the distinction between “framework” and “content” values as characteristic of the liberal, Anglophone wing of the Enlightenment tradition (in contrast to the continental, engineering-oriented wing), see Carus (2007, pp. 296-7ff.). 26 “Roughly” since not everyone accepts every current theory (or alleged fact) in every scientific and historical discipline. But there will be an “overlapping consensus” among all those who use the scientific vernacular, and the ultimate source of this overlap — empirical evidence — is a more compelling motivation than the supposed “reasonableness” of the contending “comprehensive doctrines” that drives Rawls’s well-known version of such an overlapping consensus (Rawls 1996, pp. 58-66). Of course it could perhaps be argued that all Rawls means by “reasonableness” here is, in fact, a willingness to accept and use the scientific vernacular.

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5. Carnapian Rationality

Critiques of Carnapian rationality come in many forms, so it is hard to address them comprehensively.

But one widely-discussed form of the first criticism discussed above is that of Quine, whose basic

complaint is that Carnap does not rest content with a standpoint internal to science, in mediis rebus

(Dreben 1994), but insists on stepping outside the “conceptual scheme” of working science and

appraising it from an external perspective. Most forms of the second criticism, e.g. from a modernized

Kantian standpoint such as that of Habermas or Rawls, have just the opposite complaint. For them,

Carnap’s external standpoint is too modest. The external perspective Carnap is willing to

countenance, in their view, is insufficiently robust in that it allows too little scope for practical reason

to yield substantive principles of morality, even of the extremely formal kind that Kant found in the

categorical imperative.

The actual Carnap, though, proceeds from a starting point in which our cognition is just as entangled,

just as much in mediis rebus, as Quine or Putnam. Language users, in Carnap’s view, are also

participants in the world that a language is about. They are not just representers, and consumers of

representations, but also agents in the world so represented. Unlike Quine (or Putnam in some of his

moods), however, Carnap thought that we can also step back from that existential Geworfenheit of

having to act and facing choices. We can abstract from it and isolate certain features from immediate,

deeply entangled experience. We can separate out a purely representational (or semantic) component

of language from its pragmatic embeddedness in a world of agent-users. (If we were unable to do this,

our species would have been trapped from the outset in Parmenidean paralysis; cognitive life could

never have got off the ground.) For everyday scientific and technological purposes, this semantic

abstraction works smoothly and requires no help from pragmatics. Indeed, the cognitive progress of

the species depends, to a large degree, on our institutionalization of this and similar feats of

abstraction. But when the need for explication or language change arises, semantics is no longer self-

sufficient. The choice among explications (as Thomas Kuhn emphasized in different words, from a

different perspective) is external to the particular language framework(s) under consideration (Stein

1992, p. 280). 27

27 A comparison of Kuhn and Stein in this respect, with particular emphasis on Stein’s Carnapian pragmatics, is to be found in Carus (2013).

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Carnap’s approach to this predicament differs sharply from Quine’s. Quine excluded external

discourse altogether, and so had to take the mother tongue at face value, i.e. in a universal sense.28

Carnap too excluded external discourse, including questions about the truth or the nature or the

existence of something without reference to a language. But for him this exclusion extended only to

semantics, where the user-as-agent is abstracted away. Faced with a problem that points beyond

semantics, a problem that puts the concepts themselves or the constitutive rules of the language into

question, we retreat – not to a “mother tongue,” as Ricketts (2004, p. 199) maintains — but to

pragmatics, where the user is once again an actor in the world represented, and there are choices to be

made.29 The inescapability of choice does not, however, mean we must retreat to to the arbitrariness

and inconsistency of ordinary language, or to the immediacy of a Lebenswelt. Of course we live —

inescapably — in a Lebenswelt, but pragmatics, unlike the mother tongue, affords us tools to transcend

it when we need to (just as language, especially written language, gives us tools to transcend the

limitations of immediate subjective consciousness). Descriptive pragmatics draws on our entire fund

of empirical knowledge (specifically on our knowledge about knowledge), and pure pragmatics enables

us, by whatever standards we set ourselves, to understand and act in conformity with the consequences

of our provisionally chosen values (and revise them if we cannot accept those consequences).

In this limited sense, though, Carnap did, in contrast to Quine, insist on the availability of an external

perspective, from which criticism of our knowledge and our language is possible (e.g. George 2012).

An example of such a perspective is his posthumously published discussion of entropy in

thermodynamics (Carnap 1977). In the process of seeking an abstract definition of entropy for

purposes of inductive logic, he also looked at the “nature of the physical concept of entropy in its

classical statistical form, as developed by Boltzmann and Gibbs,”

. . . and I arrived at certain objections against the the customary definitions, not from a factual-experimental, but from a logical point of view. It seemed to me that the customary way in which the statistical concept of entropy is defined or interpreted makes it, perhaps against the intention of the physicists, a purely logical instead of physical concept; if so, it can no longer be, as it was intended to be, a counterpart to the classical macro-concept of entropy introduced by Clausius, which is obviously a physical and not a logical concept. The same objection holds

28 This is the upshot of the “reciprocal containment” discussed by Ricketts (2009); on Quine’s “universalism” cf. Hintikka 1990 and Quine’s (1990) thin-skinned but hardly convincing response. 29 Michael Friedman’s (2001, pp. 47-68, 105-15; 2011, pp. 712-29) argument to the effect that object-level Kuhnian incommensurability (e.g. during scientific revolutions) can coexist with meta-level rationality at the level of philosophical or meta-scientific debate (e.g. the debate about geometry between Poincaré and Helmholtz as a backdrop to Einstein’s introduction of relativity) makes essentially this same point; Carnap would have classified such meta-scientific debate as belonging to descriptive pragmatics.

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in my opinion against the recent view that entropy may be regarded as identical with the negative amount of information. (Carnap 1963, pp. 36-7)

He was unable, to his own disappointment, to get this idea across to the physicists at Princeton,

“chiefly,” he surmised, “because of great differences in point of view and language.” Regardless of the

merits of Carnap’s critique30 in this particular case, it illustrates the sort of external, critical

perspective he regards as legitimate and suggests how it could be extended to other aspects of

scientific practice. Such a perspective is not available to Quine, who would in any case have rejected

Carnap’s central distinction between “purely logical” and “physical” concepts of entropy. More

generally, though, choices among language forms do not fall within the scope of Quine’s conception of

philosophy as continuous with science.

Along the lines of Carnap’s entropy example, one could imagine critiques showing, for instance, that

certain features of the classical game theory used in economics or political science are at variance with

accepted empirical facts, or with theories in other disciplines. From here it is a short step to more

general systems of practical reason in which e.g. consistency among various normative principles is

itself at issue, or of course consistency between normative principles and observed practices.

This use of “consistency” (which implies a background logic) may appear to be in tension with

Carnap’s statement in the “value concepts” fragment that “all logic, including inductive logic, and

factual knowledge are irrelevant” to any constraints on the rationality of comprehensive value

functions. But as we saw above, this can hardly be taken literally, as such constraints are impossible to

state in “pure optatives” alone, i.e. without some factual component, as Carnap recognized in labelling

that component “descriptive pragmatics.”

Nor is there anything circular about the use of logic or facts in their capacity as descriptive pragmatics.

What we use at the pragmatic level, for purposes of choosing among frameworks or explications, as our

working conception of reason, is (just as in the case of inductive axioms) provisionally fixed. We have

at our disposal all the knowledge available via that provisionally fixed meta-framework, to inform us, as

well as is currently possible, about the consequences of selecting any given framework. This does not

mean that either the meta-framework or the knowledge framed in it is inviolate or frozen in place (as 30 See Shimony (1975) for a balanced discussion, which however appears somewhat to misconstrue the aims of Carnap’s critique.

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Carnap’s rhetoric sometimes — misleadingly — suggests). It is, from the viewpoint of the individual or

group making choices among concepts or systems of concepts, the best available right now. Nor is it

applied inductively to select frameworks that, in turn, define what is to be counted as knowledge.31

The role of descriptive pragmatics can never be more than a supportive, “heuristic” one; the logical

and empirical knowledge employed as descriptive pragmatics cannot decide the issue, it can only

inform decision-makers of the consequences of their choices.

So Carnap, in contrast to Quine, left room for an external perspective, even a critical and valuational

perspective, on scientific knowledge. But in contrast to Kant, or most philosophers from the Kantian

or German idealistic or phenomenological traditions, Carnap did not think this perspective could yield

anything more than critique; he did not think we could actually find out anything, either about facts or

about values, from this external perspective. He did not think that Vernunft could give us a categorical

imperative any more than he thought could it give us synthetic a priori knowledge. The most it could

do — though this was of overriding importance — was to guide Verstand, the search for knowledge, by

the wider view it offered.32 And this wider view afforded by the perspective of Vernunft could in turn

be informed and disciplined by the progressively better and more comprehensive picture of the world

given us by (Vernunft-guided) Verstand. This is certainly not the “criterial” conception of rationality

Putnam (1983) saw and criticized in Carnap, but the modesty of this picture also sets it apart from the

great majority of ethical projects in any tradition.

One reason it does not emerge clearly from Carnap’s writings is, of course, that he had not fully

worked it out and was otherwise preoccupied. But another reason, it has to be admitted, is Carnap’s

own rhetorical clumsiness. The language he used regarding the “a priori” and the “analytic” (not to

mention “intuition”) was, as we saw above, highly misleading as a way of explaining what he was

actually trying to get across. Likewise, to articulate his idea of holding higher-level inductive

principles provisionally fixed while choosing from the range of possibilities they still left open, he often

conveyed a rigidity that was, in fact, quite alien to the conception he actually had in mind.

31 Which would invite the kind of circularity charge sometimes levelled at Quine, discussed in depth by Gregory (2008); cf. also the review of Gregory’s book by Burgess (2009). 32 Michael Friedman provides good examples of this in his cases of philosophical, meta-scientific debate guiding object-level scientific change (footnote 30 above).

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These rhetorical failings, though exasperating, need not cloud our appraisal of the architectonic of

rationality Carnap was feeling his way toward in his later years. Once we unpack his scattered remarks,

we can see that there is actually quite a powerful vision behind them, an overall perspective from which

scientific rationality and ethical values fit into a single coherent conception without sacrificing the

pluralism, tolerance, and engineering constructivism that characterize Carnap’s ideal of explication. It

no longer looks impoverished or defective in the ways it is often portrayed to be; in fact it is coherent at

quite a deep level, lends itself to ampliative development as suggested by Stein and Uebel, and could

well repay further elaboration.

Unpublished Sources

Documents cited are from two different collections, the Carnap papers at the Archives of Scientific Philosophy at the Hillman Library, University of Pittsburgh (abbreviated ASP/RC) and the Carnap papers (manuscript collection no. 1029) at the Young Research Library, University of California at Los Angeles (UCLA). Citations are by collection, followed by location, thus ASP/RC followed by three numbers separated by hyphens (ASP-RC XX-YY-ZZ, where XX is the box number, YY the folder number, and ZZ the item number) or UCLA followed by box, folder, and sometimes page numbers. The texts are quoted by permission of the University of Pittsburgh and the Carnap heirs, respectively, which is gratefully acknowledged.

Published Literature Cited

Burgess, J.P. 2009 Review of Gregory 2008, Notre Dame Philosophical Reviews, 19 May 2009. Burks, A. 1953 “The Presupposition Theory of Induction” Philosophy of Science 20, pp. 177-97. Burks, A. 1963 “On the Significance of Carnap’s System of Inductive Logic for the Philosophy of Induction” in P.A. Schilpp, ed. The Philosophy of Rudolf Carnap (LaSalle, IL: Open Court), pp. 739-59. Carnap, R. 1950a Logical Foundations of Probability (Chicago: University of Chicago Press). Carnap, R. 1950b ‘Empiricism, Semantics, and Ontology’, repr. in his Meaning and Necessity, 2nd edition (Chicago: University of Chicago Press 1956), pp. 205-221. Carnap, R. 1952 The Continuum of Inductive Methods (Chicago: University of Chicago Press). Carnap, R. 1962 “The Aim of Inductive Logic” in E. Nagel, P. Suppes, and A. Tarski, eds. Logic, Methodology, and Philosophy of Science: Proceedings of the 1960 International Congress (Stanford, CA: Stanford University Press), pp. 303-18.

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