Tuesday 1 December 2015

My Theory of Truth and Justification

My views on truth and justification (my epistemology more generally, in fact) has undergone quite a change in recent times. With my apostasy from Catholicism, I stopped having a view I had termed Christian reliabilism (sketch here), and I could have easily just moved from a peculiarly Christian version of it towards a secular form by subtracting truths that were justified on the basis of divine revelation.

Instead, I recently had my interest piqued by a pragmatic theory of truth via the physicist Sean Carroll which says that "we should always act as if A is true" implies that A is true. Whilst I previously held a correspondence theory of truth, I found it hard to justify much knowledge at all because it was difficult to see how I could justifiably access that exterior world to check if truths corresponded. But, as interesting as pragmatism was as an alternative, I strongly disliked how under-determined it was: as far as I could tell, it offered no resources for distinguishing between ontologically distinct but empirically equivalent beliefs. I could also conceive of it having difficulty with "inconvenient truths" and "useful falsehoods." Could they be smuggled in as false or true respectively when it would seem obvious that they are false? Someone who believed that free will did not exist may still hold that it is better to act as if it does, for instance, but that would imply that free will does exist (or technically, "is true").

There is an interesting feature of the definition of truth that pragmatism has which may have consequences I do not currently foresee: it is based on an ought statement. If someone believes strongly in the is-ought gap, then defining that something is true based on what ought to be done/believed is going to be a problem. Or alternatively, one can think of this definition as the beginning of a solution to the is-ought gap's related problems. It is at least conceptually odd, even if true(!), that an ought statement gives a definition of truth. If, like me, you think oughts may imply teleology, then an important question to ask would be: we ought to...if what? We ought to believe A if we want to be come billionaires? Win a Nobel prize? Colonise Mars? Have seventeen children? I would refine the imprecise definition that Carroll suggested he was partial to by adding in something along the lines of "ought to...if we want to make accurate predictions about the world" or perhaps "...of our experience of the world." There is then subsumed into the theory what we originally found to be an important part of the definition of truth, that is, that it has something to do with how the world is.

Pragmatism about truth avoids a substantial amount of scepticism which seems to follow from a correspondence theory of truth, but perhaps one of its most appealing consequences is how you can get shades of truth and falsehood. Whilst something is only true if we ought always to act as if it were true, it is relatively easy to add in provisions about partial truths by saying that they refer to propositions that we should sometimes act as if true. For instance, it is relatively easy on this view to say that classical mechanics is partially true insofar as their is a classical regime in which we should act as if classical physics is true, even though that classical regime is not the most general regime possible.

However, that under-determinism aspect of it jars at me a lot, so eventually I clicked on a compromise: we can have pragmatism as a theory of justification and keep some kind of correspondence as a theory of truth. This would say that a person is justified in believing A if they should always act as if A is true, and yet, A is only actually true if it corresponds to how the world really is. This benefits from avoiding scepticism and explaining how we can have partially justified beliefs without allowing that there are a possibly infinite number of contradictory "truths" which count as true because they are empirically equivalent.

Obviously a lot more refining needs to take place, but I think this understanding of truth, justification and their interplay may even get me out of my most begrudgingly sceptical position: scientific anti-realism. If justification via pragmatism is a reasonable position, then it seems to follow that scientific realism is a reasonable position, and as someone that aspires to work in the natural sciences, that would be great.

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