Is Putnam’s Internal Realism Solipsistic?

Javier Toro

Abstract

In this essay I claim that Hilary Putnam’s recent rejection of his former doctrine of internal realism as solipsistic is a misfired claim. Putnam’s rejection of his early doctrine is illustrated by the criticism of his own verificationist account of truth and justification, which is based on the counterfactual conditional: “S is true if and only if believing S is justified if epistemic conditions are good enough”. By accepting that whatever makes it rational to believe that S also makes it rational to believe that S would be justified were conditions good enough, Putnam concludes that the verificationist unavoidably steers between solipsism and metaphysical realism. As opposed to this, I claim that Putnam’s later criticism of his own internal realism fails to acknowledge the pragmatic side of this philosophical approach; namely, the idea that, regardless the close relation between truth and justification, not all sentences in a language game are to be understood in a verificationist fashion. Thus, the understanding of the counterfactual “S would be justified if epistemic conditions were good enough” doesn’t call for a verificationist reading, which, as Putnam claims, yields solipsism, but rather, for a pragmatic approach which emphasizes on the non-formality of language understanding.

Key words:Putnam; realism; pragmatism; truth; correspondence

In a recently published review of Hilary Putnam’s latest book Philosophy in an Age of Science, Jerry Fodor writes: “it would take at least two workaday philosophers to keep up with Hilary Putnam” (Fodor 2013: 30). As extreme as that sounds, Fodor is not exaggerating when he also says that Putnam is one among the few philosophers who can say important things about “the philosophical interpretation of quantum mechanics, the philosophy of mind, the philosophy of language, the philosophy of mathematics, philosophical ethics (analytic and otherwise), and the debate between solipsists, phenomenologists and realists about the epistemological and metaphysical status of ‘external’ objects” (Fodor 2013: 30). Without necessarily being one of Fodor’s “workaday philosophers” trying to keep up with Putnam’s work in each and every one of these areas, I will address in this essay one of the topics to which Putnam has shown a good deal of concern in his latest publications, namely, the relation between solipsism and his former doctrine of internal realism.

In his latest book, Philosophy in an Age of Science (2012), as well as in recent publications, Putnam has repented from his doctrine of internal realism because, as he came to see it, it amounted to a Cartesian epistemological picture which that ultimately becomes solipsistic. In fact he admits that: 

On a verificationist account of understanding […] the only substantive notion of correctness available to a thinker is that of being verified. If that is the only notion of correctness that my ‘mind/brain’ is supposed to be able to use […] then my talk about other people is only intelligible to me as a device for making statements that are or will be verified by my experiences. (Putman 2012: 79)

Since verificationism, as now Putnam sees it, renders internal realism solipsistic, he has come to reject the coherence of this doctrine. Such rejection has led him into the adoption of natural realism (inspired by William James), namely, the pragmatist idea which insists that objects are perceived immediately and corrigibly (as opposed to inferentially through sense data).

As opposed to Putnam himself, I will argue that his former doctrine of internal realism is an anti-skeptical doctrine, which is more in accordance to the main tenets of pragmatism than his recent writings are. Thus, under this interpretation, internal realism, by adopting a justificationist approach to beliefs and truth, not only becomes an alternative to the metaphysical realism opposed both by Putnam and the classical pragmatists, but also becomes a relevant account of belief construction.

Of course, one cannot ignore the many criticisms which that have fallen upon internal realism (Devitt 1984, Putnam, 1990, 1999, 2012). In this essay I follow Putnam’s criticism of his former talk about qualia (Putnam 1999), which was supposed to afford the “ideal epistemic conditions” in internal realism. Though now he accepts the possibility of such talk (Putnam 2012), what he said about this topic in his Threefold Cord seems very relevant. Therefore, since the topic of Putnam’s drifting attitude towards mental qualia is so vast, in this essay I will simply take for granted that the criticisms of The Threefold Cord against the meaningfulness of the internal realist’s talk about qualia are much to the point.

Thus, keeping in mind that internal realism is far from being a perfect doctrine which, by the way, more than a doctrine, like pragmatism, would be a philosophical attitude, in this essay I will insist that Putnam’s rejection of his former doctrine and his charges of solipsism are misfired.

1.

Putnam’s “internal realism” defends the idea that “elements of what we call ‘language’ or ‘mind’ penetrate so deeply into what we call ‘reality’ that the very project of representing ourselves as being ‘mappers’ of something ‘language-independent’ is fatally compromised from the very start.” (Putnam 1990: 28) This philosophical approach, which started with his 1978 article “Realism and Reason”, and finished around the publication of his collection of essays in Realism With a Human Face, in 1990, was meant to be a reaction against the “strangle hold which a number of dichotomies appear to have on the thinking of both philosophers and laymen. Chief among these is the dichotomy between objective and subjective views of truth and reason.” (Putnam 1981: ix). The main objective view of truth and reason which that Putnam opposed with his internal realism was Metaphysical Realism, the doctrine which holds that “the world consists of some fixed totality of mind-independent objects. There is exactly one true and complete description of ‘the way the world is’. Truth involves some sort of correspondence relation between words or thought-signs and external things and sets of things.” (Putnam 1981: 49) As opposed to this, internal realism holds that the question “what objects does the world consist of? is a question that it only makes sense to ask within a theory or description.” (Ibid.)

However, internal realism, for Putnam, was a short-lived approach to philosophy. Around 1990 (in the “Response to Simon Blackburn”, in Putnam 1994), he started to find flaws in this doctrine and began to move towards, what he calls, “natural realism”, inspired by William James’s radical empiricism. In different places, Putnam has described internal realism as a position which commits itself to the metaphysical doctrines which was supposed to combat. For example, the heart of internal realism, as Putnam claims, was verificationist semantics, inspired by Michael Dummett; in Putnam’s version of that semantics “truth, was identified with verifiability under epistemically ideal conditions.” (Putnam 2012: 25) Thus, according to the Dummettian view of verificationist semantics, which Putnam accepted, “to grasp the meaning of a statement is to know what would justify asserting it or denying it.” (Dummett 2004: 114) The core of the problem is related with the referential access to and justification of such epistemically ideal conditions for, under the internalist picture, “the world was allowed to determine whether I am in a sufficiently good epistemic situation or only seem to myself to be in one.” (Putnam 2012: 25) For Putnam, such situation presupposes the Cartesian dualism –which he has always rejected between a passive observer and the World. Putnam eventually abandoned this internalist picture because it relied on two epistemic features which he came to reject: the idea of conceptual schemes as being the only reality of which we can speak of, and the acceptance of sense data or qualia as the main elements of perception:

On my alternative picture the world was allowed to determine whether I actually am in a sufficiently good epistemic situation or whether I only seem to myself to be in one –thus retaining an important idea from commonsense realismbut the conception of an epistemic situation was, at bottom, just the traditional epistemological one. My picture still retained the basic premise of an interface between the knower and everything ‘outside.’ (Putnam 1999: 18)

The importance of such mental qualia was that, on the internalist picture, it served as the basis for the conceptualization of reality:

On the ‘internal realist’ picture it is not only our experiences (conceived of as ‘sense data’) that are an interface between us and the world; our ‘conceptual schemes’ were likewise conceived of as an interface. And the two ‘interfaces’ were related: our ways of conceptualizing, our language games, were seen by me as controlled by ‘operational constraints’ which ultimately reduce to our sense data. (Putnam 2012: 26)

Thus, in his 1994 Dewey Lectures, Putnam rejected internal realism because, as he then saw it, it used conceptual schemes and sense data as an interface between the mind and reality. According to him, all we could know under internalist constraints were linguistic constructions based on unverifiable mental qualia. For this reason, Putnam has abandoned the internalist picture and has adopted instead the Jamesian doctrine of natural realism; a doctrine which sees us “as open to the world, as interacting with the world in ways that permit aspects of it to reveal themselves to us.” (Putnam 2012: 27)

Nevertheless, Putnam has recently accepted that talk of mental qualia makes good sense, and thus, his rejection of internal realism now centers on charges of solipsism and lack of public intelligibility.

2.

In a recently published article called “Corresponding with Reality”, Putnam claims that his internal realism, due to the solipsism of its “verificationist semantics”, “far from being an intelligible alternative to a supposedly unintelligible metaphysical realism, can itself possess no public intelligibility.” (Putnam 2012: 80) The reason is that, as Putnam now sees the issue, verificationist semantics restricts the range of justification to those sentences which can be verified only by me, leaving no room for intersubjectivity. As he admits, though, in Reason, Truth, and History he was already aware of such danger, and thus, in that book he defined “an intersubjective notion of truth in terms of verification (“justification”) thus: S is true if and only if believing S would be justified if epistemic conditions were good enough.” (Putnam 2012: 79) But, as the criticism goes, according to this sort of verificationism, understanding a sentence amounts to understanding a counterfactual whichthat confirms it:

Let us suppose, as seems reasonable, that whatever makes it rational to believe that S makes it rational to believe that S would be justified were conditions good enough. If my understanding of the counterfactual “S would be justified if conditions were good enough” is exhausted by my capacity to tell to what degree it is justified to assert it, as my “verificationist semantics” claimed, and that is always the same as the degree to which it is justified to assert S itself, then I might as well have simply said that my understanding of S is just my capacity to tell what confirms S. (Putnam 2012: 79)

By equating the understanding of a sentence to the “internal” capacity to decide on its confirmation, verificationst semantics, the core of internal realism, becomes a solipsistic option. Thus, as Putnam came to see it, internal realism is a solipsistic doctrine because it accepts that what makes a statement true is also supposed to be what the statement means, in other words, my understanding of S is just my capacity to tell what confirms S to what degree. It is in this way that, according to Putnam, internal realism (and verificationism) conflates meaning and justification: if the meaning of a statement is exhausted by my capacity to tell what justifies it, then, by restricting the meaning of sentences to individual means of justification, one falls into solipsism. The problem of solipsism, so present in philosophy since the Cartesian cogito, is an unacceptable position for the pragmatist or the internal realist. It is unacceptable because it implies that the meaning of words is determined by internal and individual criteria, and not by social criteria. Therefore, such arguments like the Cartesian cogito and the Brains in a Vat argument, do not reflect the importance that intersubjectivity has for internal realism.

In what follows I will argue that such criticism of internal realism is misfired, since Putnam wrongly equates the understanding of a fact (S) with the understanding of a counterfactual (1) “S would be justified if epistemic conditions were good enough”. More than committing a logical blunder –which is almost unthinkable in the case of Putnam, I will argue that his later rejection of his former doctrine of internal realism overlooks the importance of pragmatist holism, namely, the idea that the knowledge of certain specific rules of language games is a necessary condition for the belief of certain facts.

Both, in the above cited article, as well as in his article “Between Scylla and Charybdis: Does Dummett Have a Way Through?” published in the volume The Philosophy of Michael Dummett, Putnam conflates the meaning of counterfactual (1) with the meaning of S, which is obviously not the case. To see how he comes to this conclusion, let’s inquire what does it mean that the verificationist, according to Putnam, is trapped by solipsism by accepting that his understanding of S is the same as his capacity to tell what confirms S.

For Putnam it is reasonable to suppose “that whatever makes it rational to believe that S makes it rational to believe that S would be justified were conditions good enough.” (Putnam 2007: 162) But, he continues, this apparently “reasonable” claim leads the verificationist straight into solipsism:

If my understanding of the counterfactual “S would be justified if conditions were good enough” is exhausted by my capacity to tell to what degree it is justified to assert it, and that is always the same as the degree to which it is justified to assert S itself, why did I bother to mention the counterfactual at all? Why did I not just say that my understanding of S is just my capacity to tell what confirms S to what degree, full stop? (Ibid.)

According to this, the counterfactual (1) “S would be justified if conditions were good enough”, is equated to S itself, which is a very long stretch. What Putnam fails to see is that (1) is a condition for S, not the other way around: let us suppose that S stands for the belief in the existence of saber-toothed tigers 30.000 years ago (an example of Putnam’s). Then, according to verificationist semantics, S would be true if it is justified by epistemic conditions such as the acceptance of archeological evidence, the fossil record and all the scientific knowledge which surrounds such evidence. However, at the same time, S is indirectly justified by the understanding and acceptance of (1) as an epistemic principle, not the other way around: the capacity to tell to which degree it is justified to assert (1) is not the same as the degree to which it is justified to assert S. That (1) is a condition of S, and not the other way around, is clear because one cannot meaningfully say that

 “The belief in the existence of saber-toothed tigers 30.000 years ago would be justified if epistemic conditions were good enough” is true if and only if the belief in the existence of saber-toothed tigers 30.000 years ago is true.

What makes the belief in the existence of saber-toothed tigers 30.000 years ago true –according to the verificationistis the understanding that such belief would be true if and only if epistemic conditions were good enough.

Then, as was shown, the capacity to tell to which degree it is justified to assert (1) is not exhausted by the capacity to tell to which degree it is justified to assert S. The verificationist expects that all true beliefs are justified; but what justifies my belief in a fact S is not the same as that which justifies my belief in counterfactual (1). Ultimately, of course, both are justified linguistically, but that is not what is at stake here. What is at stake is the charge that verificationism is solipsistic because it equates the meaning of sentences with their internal justification, which, as we have seen, amounts to the conflating of the capacity to tell to which degree it is justified to assert S with the capacity to tell to which degree it is justified to assert (1).

Now, however, we must face the question whether verificationist semantics is itself justified according to its own standards. In other words, since what renders true and justifies the belief in every sentence S is the acceptance of the counterfactual (1), which asserts that S is justified if conditions are good enough; then, what justifies the belief in counterfactual (1)? It seems rather strange to justify the statement “a sentence is justified if epistemic conditions are good enough” by saying that what justifies it is that a statement is justified if epistemic conditions are good enough! Thus, trying to justify (1) by appealing to (1) itself leads us to a circular argumentation.

In Reason, Truth, and History, Putnam says that “a non-realist or ‘internal’ realist regards conditional statements as statements which we understand (like all other statements) in large part by grasping their justification conditions.” (1981: 122) Therefore, like all other statements which are justified by their epistemic conditions, we accept (1) for its epistemic conditions. The problem is that (1) is itself the very “principle” which says that a statement is justified due to its epistemic conditions. We are facing here something similar to a Convention-T sort of sentence: “S is justified if conditions are good enough” is true if and only if S is justified if conditions are good enough. It is this sort of coherentism –criticized by Putnam long ago in his Model Theoretic Argument (Putnam 1983)- )– which makes him now believe that his former doctrine of internal realism is solipsistic. Thus, in his latest writings, Putnam has found that for the verificationist there is no way out of this coherentism, and therefore verificationism amounts to solipsism. In what follows, I will argue that statements such as (1) are not to be understood as principles in need of verification, but rather as pragmatic conditions for our linguistic practices; then, the only possible option that the verificationist has for her belief in (1) is a non verificationist way, a pragmatic way.

3.

As we have just seen, the conditional “S would be justified if conditions were good enough” is not to be understood as the meaning of S itself, as the later Putnam pretends, but rather, as a pragmatic condition for the meaning of S. Such move, as was explained above, avoids the charges of solipsism which Putnam levels against his former doctrine of internal realism. However, as we just pointed out, such conditional cannot be itself understood in a verificationist way, since it would end up in a circular argumentation. To see a possible (non-solipsist and non-circular) way to understand such conditional I propose to approach it pragmatically.

Both, in his 2007 and his 2012, Putnam reminds us that by the time he wrote Reason, Truth, and History, and defined truth as idealized justification, he wasn’t aware of the solipsist “dilemma” of conflating the meaning of a sentence with its assertability conditions. Nevertheless, in that book, not only he mentions that the “‘internal’ realist regards conditional statements as statements which we understand (like all other statements) in large part by grasping their justification conditions” (Putnam 1981: 122), but also emphasizes that such justification conditions are objective: as opposed to the “methodological solipsist” and relativist, the internalist position

assumes an objective notion of rational acceptability. The non-realist rejects the notion that truth is correspondence to a ‘ready-made world’. That is what makes him a non(metaphysical)- )realist. But rejecting the metaphysical ‘correspondence’ theory of truth is not at all the same as regarding truth or rational acceptability as subjective… The whole purpose of relativism, its very defining characteristic, is, however, to deny the existence of any intelligible notion of objective ‘fit’. Thus the relativist cannot understand talk about truth in terms of objective justification-conditions. (Putnam 1981: 123)

Thus, the internalist understanding of conditionals depends on an objective notion of rational acceptability, which, of course, is different from a correspondence theory of truth. However, we may ask, if the internalist is not assuming a metaphysical correspondence between language and reality, then, what is this notion of “objective fit” which he assumes and the solipsist and relativist deny?

Unfortunately, in Reason, Truth, and History, Putnam doesn’t give a clear and satisfactory answer to this question. The closest he gets is by emphasizing that truth, rather than correspondence to facts, is idealized assertability. But, since the notion of idealized assertability implies the very notions of verificationist semantics and conditionals which we are trying to understand, it seems that such an answer won’t take us very far. However, in his Pragmatism: An Open Question, Putnam rehearses an answer which I think is on the right track. In the chapter called “Was Wittgenstein a Pragmatist?”, Putnam criticizes philosophers like Richard Rorty, Michael Williams, and Paul Horwich, who, according to him, read Wittgenstein as supporting the idea that language use is based on definite criteria. Thus, “the heart of Rorty’s reading of [Wittgensteinian language games] is his comparison of criteria with programs… Rorty sees language games as virtually automatic performances.” (Putnam 1995: 33-4) Although not very far from Rorty’s approach to language games,

[o]n Horwich’s view, a language game is to be understood as consisting of sentences for which (if we confine attention to assertoric language) there are ‘assertability conditions’. These conditions specify that under certain observable conditions a sentence counts as true or at least as ‘confirmed’… Note that this account differs from Rorty’s only in that the ‘criteria’ which govern our use of words provide (in some cases) for degrees of assertability less than certainty. Still, speakers who understand their language in the same way and who have the same evidence should all agree on the degree of assertability of their sentences, in this model, just as in Rorty’s. (Putnam 1995: 45-6)

This paragraph makes us wonder if, due to the emphasis on the degree of assertability of sentences, such positivistic interpretation of Wittgenstein (as Putnam calls it) parallels the internalist account. The main difference between this positivistic reading of Wittgenstein and Putnam’s own pragmatist reading (which, as I claim, amounts to his internal realism) is that the first account takes sentences as marks and noises, for which assertability is separated from truth: under certain observable conditions a sentence counts as true. As opposed to this, Putnam’s pragmatist reading of Wittgenstein insists on the idea that “the use of the words in a language game cannot be described without using concepts which are related to the concepts employed in the game.” (Putnam 1995: 46) This means that language games are not ruled by a definite set of criteria, a set which, if one pays attention enough, one would learn how to use; but rather, that language games are self-contained forms of life:

Someone who doesn’t see the ‘point’ of the language game, and who cannot imaginatively put himself in the position of an engaged player, cannot judge whether the ‘criteria’ are applied reasonably or unreasonably… Understanding a language game is sharing a form of life. And forms of life cannot be described in a fixed positivistic meta-language… (Putnam 1995:47-8)

Whereas the positivistic reading of Wittgenstein takes criteria to be exterior to the language game, as some external aid we use when it comes to understand language games, Putnam’s pragmatist reading of Wittgenstein sees language games as forms of life which cannot be described without using the same concepts which are internal to the game itself. That is why someone who cannot imaginatively put himself in the position of an engaged player cannot judge whether the ‘criteria’ are applied reasonably or unreasonably. Under this interpretation, the idea that assertability conditions are external to the truth of statements is ruled out. For Putnam, assertability and truth are internally related notions:

To know under what conditions a statement (not a ‘sentence’) is assertable is to know under what conditions it is true or liable to be true. The idea that assertability conditions are conditions for making a noise is a total distortion of Wittgenstein’s meaning. ‘Assertability’ and ‘truth’ are internally related notions: one comes to understand both by standing inside a language game, seeing its ‘point’, and judging assertability and truth. (Putnam 1995:48-9)

If the assertability conditions of a statement are not separated from its truth, then, it doesn’t make sense trying to apply separate criteria to statements in general, which would be an unnecessary and artificial move. In order to understand the statements of every language game one must stand inside it and know that the truth of one’s words are related to their assertability conditions, to the effect that both are to be judged uniformly. Of course, as verificationist semantics shows, every language game has internal rules which one must follow, and one such internal rule of our language game is that we pragmatically accept that a statement is justified if conditions are good enough. This rule of our language game, together with all our other cognitive ideals, “only makes sense considered as part of our idea of human flourishing.” (Putnam 1995: 43)

4.

Now we are in a better position to understand Putnam’s internalist conditional that “S is justified if epistemic conditions are good enough”. We said above that such conditional couldn’t be understood in a verificationist fashion, since it would imply a circular argumentation. In the same way, the positivistic reading of Wittgenstein which Putnam criticizes doesn’t help in understanding sentences like “S is justified if epistemic conditions are good enough” because the meaning of the sentence itself makes reference to a principle of justification conditions for sentences. As was pointed above, establishing assertability conditions or criteria for such a sentence leads us into a circular argumentation; thus the need to understand such sentence non-criterially. Putnam’s reading of Wittgenstein affords us with the possibility to understand such conditionals in a pragmatist way: one can only understand the conditional that a statement is justified if conditions are good enough if one shares a certain language game. Strangely enough, in “Corresponding With Reality” (in his 2012), the very article in which Putnam charges internal realism of being solipsist, he himself, towards the end, reminds us the importance of Wittgensteinian “imponderable evidence” (as he did in his Pragmatism: An Open Question) when it comes to justification. As Putnam sees it, “[not] only what is shaped like a proposition can justify a proposition.” (Putnam 2012: 89) Thus, the criteria of verification for the internal realist is not limited only to propositions, but it is open to other means of verification. By asking to criterially justify the convention of our language game, which asserts that a statement is justified if conditions are good enough, Putnam seems to ignore his own pragmatist reading of Wittgenstein. This interpretation seems to be also in line with Putnam’s approval of what Stanley Cavell (in a very pragmatist tone, reminiscent of Peirce) has said about skepticism and justification, namely that in order to understand language games and avoid skepticism, one must be attuned in them.

This is actually not very far from Michael Dummett’s account of justification through language learning: “when we acquire the practice of using language, what we learn is what is taken to justify assertions of different types.” (Dummett 2004: 114) Internal realism, far from being the solipsist doctrine which Putnam now claims it to be, gives us a clue to our justificatory practices by pointing out to one of our more accepted rules of justification, namely, the condition that a statement is justified if the epistemological conditions for stating it are good enough.

The understanding of this conditional is not a metaphysical bedrock, a condition for understanding language in general; but rather, it makes part of what it is to share a form of life. It would indeed be natural for a skeptic who didn’t share our language game to doubt this conditional. Such a skeptic would probably not be satisfied until one provides him an argument similar to Descartes’s cogito argument, an argument where, only apparently, the metaphysical bedrock of certainty was reached. Such a skeptic, naturally, would not be satisfied with the pragmatist argument that I am associating with Putnam (as he himself associated it with Wittgenstein) either; which shows that, after all, Putnam’s interpretation of Wittgenstein still seems to the point when he says that “the possibilities of ‘external’ understanding of a deeply different form of life are extremely limited.” (Putnam 1995: 50)

Putnam’s latest choice of trying to understand the conditional “S is justified if conditions are good enough” by applying criteria, (as his 2007 and 2012 show), seems to be a retreat to the metaphysical realism which he has so much criticized. The idea that such conditional statement stands for justification as any other statement of our language game does is a retreat to metaphysical realism because it asks us to justify certain cognitive norms of our form of life which only a skeptic or an alien to such form of life would bring into question.

References

Baghramian, M. (Ed.). (2012). Reading Putnam. London: Routledge.

Cavell, S. (1979). The Claim of Reason. Oxford: Oxford University Press.

Devitt, M. (1984). Realism and Trut. Oxford: Blackwell.

Dummett, M. (2004). Truth and the Past. New York: Columbia University Press.

Fodor, J. (2013). C’est Mon Mètier: Putnam and Language. London Review of Books, 35(2).

Putnam, H. (1981). Reason, Truth, and History. Cambridge: Cambridge University Press.

Putnam, H. (1983). Realism and Reason, Philosophical papers, vol. 3. Cambridge: Cambridge University Press.

Putnam, H. (1990). Realism with a Human Face. Cambridge: Harvard University Press.

Putnam, H. (1992). Renewing Philosophy. Cambridge: Harvard University Press.

Putnam, H. (1994). Comments and Replies. B. Hale & P. Clark (Eds.), Reading Putnam. London: Wiley-Blackwell.

Putnam, H. (1995). Pragmatism: An Open Question. Oxford: Blackwell.

Putnam, H. (1999). The Threefold Cord: Mind, Body, and World. New York: Columbia University Press.

Putnam, H. (2007). Between Scylla and Charybdis: Does Dummett Have a Way Out? R. Auxier & L. Hahn (Eds.), The Philosophy of Michael Dummett. Chicago: Open Court Publishing.

Putnam, H. (2012). Philosophy in an Age of Science: Physics, Mathematics and Skepticism. M. de Caro & D. Macarthur (Eds.). Cambridge: Harvard University Press.

Leave a Reply

Your email address will not be published. Required fields are marked *