PHL280: Truth and Reality
Week 4: The Pragmatic and Identity Theories of Truth

    Pragmatism in general

  1. Pragmatism is a philosophical movement or outlook that originated in the United States around 1870.
  2. Its principle advocates were William James (1842-1910), Charles Sanders Pierce (1839-1914), and John Dewey (1859-1952). James is generally credited for popularising pragmatism, picking up on the ideas that Pierce had put forward 20 years earlier. But Pierce later distanced himself from the particular views attributed to him by James.
  3. After Dewey Pragmatism lost much of its momentum, largely because of the rise of modern analytic philosophy (the kind we are doing in this course), which came to see pragmatism as too vague and hazy.
  4. Since the 1970s there has been a bit of a revival of pragmatism, largely through the publication in 1979 of Richard Rorty's Philosophy and the Mirror of Nature. Others who are said to share the pragmatist outloook include Hilary Putnam, Nicholas Rescher, Susan Haack, Jurgen Habermas, and Robert Brandom.
  5. For a more detailed history see the SEP and IEP articles 'Pragmatism'.
  6. The idea

  7. There is no agreed-upon tenet held by those labelled 'pragmatists', and many attempts to characterize pragmatism are indeed vague and hazy.
  8. I propose that, for present purposes, we can take pragmatism to be summed up by the following slogan:

    Pragmatism: No difference without a practical difference.

  9. In other words: All differences are practical differences; The only differences there are are practical differences; There are no non-practical differences; etc.
  10. What is a practical difference? That's a good question, and one that pragmatism needs to say more about if the need arises. But to start with we will work with our intuitive understanding of 'practical'.
  11. Pragmatism has significant consequences. Suppose you and I each have a theory about why the sun changes position in the sky throughout the day. My theory is that the sun revolves around the Earth. Your theory is that the Earth rotates on its axis. Our theories seem to be describing quite different situations, only one of which can be how things actually are. So we seem to be in dispute.

    But along comes a pragmatist and asks: what practical difference is there between these two situations? What practical difference would it make whether the sun revolves around the Earth or the Earth rotates on its axis? If the answer is 'none' then, according to the pragmatist, there is no difference at all (recall: no difference without a practical difference). In that case, the situations described by our theories are exactly the same, and there is no dispute between us. Pragmatism is thus a way of dissolving disputes.

  12. Note (and this is important), pragmatists do not just claim that we might as well take there to be no difference between these situations, or that we can take there to be no difference, or that it's a waste of time disputing the difference - they make the much stronger claim that there is no difference at all.
  13. Another illustration. Story about William James and the squirrel.
  14. Another illustration. We recently considered the question of whether or not the sentences 'Brutus stabbed Caesar' and 'Caesar was stabbed by Brutus' have the same meaning, and found it difficult to answer. What does pragmatism have to say? It would urge us to ask: what practical difference does it make whether they have the same meaning or not? If the answer is none, then there is no difference, and there is no dispute here. Does it make a practical difference?
  15. Another illustration. We think that there is such a thing as the property of being hard, and that there is a difference between things that are hard and things that are not hard. According to pragmatism, if there is such a difference then it must be a practical difference. Is there a practical difference between things that are hard and things that are not? If not, then there is no difference at all, and there is no property of being hard, which some things have and other things lack. Is there a practical difference between things that are hard and things that are not?
  16. Another illustration. Consider the dispute about whether or not God exists? Pragmatism would have us ask: What practical difference does it make whether or not God exists? If none, then there is no difference, and thus no dispute - there is no difference between a world in which God exists and a world in which God does not exist (even if the words we use to describe the two situations misleadingly suggests that there is).
  17. The pragmatic theory of truth

  18. What does pragmatism have to say about propositional truth?
  19. We are taking there to be such a property as being true, and that there is a difference between propositions that are true and propositions that are not true. According to pragmatism, if there is such a difference, then it must be a practical difference. Is there a practical difference between propositions that are true and propositions that are not true? If so, what is it?
  20. Pragmatists tend to say yes, there is a practical difference. And they tend to say that the practical difference is this: propositions that are true are useful to believe, while those that are not true are not useful to believe. This is the difference that we are getting at when we talk about propositions being true and not true.
  21. So we end up with the following theory of propositional truth:

    PT: For a proposition to be true is for it to be useful to believe.

  22. Believed by whom, and when?

  23. If we want truth to be relative, then there is an obvious answer: to be true for person s is to be useful for s to believe; to be true for people S is for it to be useful for the Ss to believe.
  24. But what if we don't want truth to be relative? Here are some things that we might say:
  25. Does PT get the direction of explanation wrong?

  26. Some propositions are useful to believe. Suppose that p is one of them. Now consider the question: Why is it useful to believe p? It is sometimes perfectly fine to give the following answer: Because p is true. (E.g. It is useful to believe that Providence is the capital of Rhode Island; Why? Because it is true that Providence is the capital of Rhode Island.)
  27. But PT does not predict this. If PT is correct, then saying that p is true amounts to saying that p is useful to believe, and the answer given amounts to this: it is useful to believe p because it is useful to believe p. Why, then, is it sometimes an informative answer?
  28. This suggests that PT gets the direction of explanation wrong. It explains being true in terms of being useful to believe, when at least some times it should be the other way around.
  29. Is pragmatism (in general) self-defeating?

  30. Suppose that pragmatism is true: all differences are practical differences. What practical difference would it have made it pragmatism had not been true - if some differences were not practical differences (i.e. some differences made no practical difference)? It seems that the answer is 'none'. But according to pragmatism, if it would have made no practical difference, then it would have made no difference at all. So, there is no difference between pragmatism being true and pragmatism not being true - we are in the very same situation in each case. That is, there is no dispute. So, if pragmatism is true, then there is no dispute between pragmatists and their opponents. In this sense, pragmatism is self-defeating.
  31. The identity theory of truth

  32. We have looked at the correspondence theory of propositional truth, according to which:

    For a proposition to be true is for it to correspond with a fact.

  33. You might also come across the identity theory of propositional truth, according to which:

    IT: For a proposition to be true is for it to be a fact.

  34. The proposition that snow is white is true. According to IT, that is because it is a fact.

    Which fact? Presumably the fact that snow is white: it would be odd to suggest that the proposition that grass is green is the fact that snow is white (for example), or any other fact apart from the fact that grass is green.

  35. Why is this called the 'identity' theory? Here might be one reason: it says that for a proposition, p, to be true is for there to be a fact, f, such that p is identical to f.
  36. But that strikes me as an odd or at least overly-prolix way of thinking about IT. Here is another way of thinking about it: it claims that the property of being true is (i.e. is identical to) the property of being a fact. It claims that one property, being true, is identical to another property, being a fact (thus the name 'identity theory').
  37. Bradley (1907), ‘On Truth and Copying’, is sometimes said to be putting forth an identity theory of truth (although this is controversial). Others who are sometimes said to endorse IT are Baldwin, Candlish, Cartwright, Moore, and Dodd 2000. For references and a more detailed history see the SEP article 'The Identity Theory of Truth'. Between 1898 and 1910 G. E. Moore and Bertrand Russell are often said to have held a version of IT. Then around 1910 they came to reject it in favor of a correspondence theory.
  38. If true propositions are facts, then at least some propositions are the same kind of thing as facts. So IT places a constraint on theories about what propositions and facts are. Any theory that says that the proposition that grass is green and the fact that grass is green are sufficiently different kinds of things that they cannot be identical, is incompatible with IT. E.g. a theory that says that the proposition that grass is green is some mind-dependent thing and that the fact that grass is green is some mind-independent thing, is ruled out by IT.
  39. Problem: Does IT, even if true, tell us much about what it is to be true?
  40. Problem: IT entails that facts are true: suppose f is fact; according to IT, to be a fact is to be a true proposition, so f is a true proposition; so f is true. But are facts the kind of thing that can be true? Is the fact that grass is green true?
  41. Problem: suppose Davidson is right that there is just one fact, call it f. Then IT is committed to there being just one true proposition. For suppose that p and q are true propositions. That means, according to IT, p is a fact. Since there is only one fact, f, p is f. Similarly, q is f. So p is q. Thus, for example, the proposition that grass is green is the proposition that snow is white. Anyone who believes that grass is green thereby believes that snow is white (they are the same proposition). Anyone who knows that 2 + 2 = 4 thereby knows that Boise is the capital of Idaho. No matter what question one is asked in a game show, one can always correctly answer that 2 + 2 = 4.

    These are pretty bad consequences - either IT or Davidson must be wrong!

  42. Further reading

Exercise

(No reading for this week - the literature on the pragmatic and identity theories tends to be too obscure.) We have now looked at four theories of truth: the correspondence theory, the coherence theory, the pragmatic theory, and the identity theory (if it even is a theory of truth). Which of these strikes you as the most promising, and why? Or perhaps you find none of them promising, in which case say why.