Monday, March 24, 2014

Truth and knowledge, personal identity

To: Joao M.
From: Geoffrey Klempner
Subject: Truth and knowledge, personal identity
Date: 7th December 2011 13:05

Dear Joao,

Thank you for your email of 28 November, with your second essay for Possible World Machine, entitled 'Knowledge is not allowed', and your notes on unit 6, on personal identity.


Well, I was expecting this. I still don't see that any mileage can be got from 'removing the requirement of truth from the definition of knowledge', although you are not the first of my students to consider this.

Of course, I can tell you what David Cameron 'knows' in his heart (or bones) about the right way to pursue economic policy -- which is information that you can use to predict David Cameron's behaviour (oh, so predictable) -- without implying that he is in the right. On the contrary, he and his party are deeply self-deceived (I say), defenders to the bitter end of big business, the monied classes, privilege etc. etc.

This is one way in which we use the term, 'know' or 'knowledge', as it were in scare quotes. But it is not the primary way. Indeed, if it were not for the primary use of the concept of knowledge there wouldn't be a 'scare quotes' use.

In the primary sense of 'know', when I say that Joao 'knows' that P, I am committed to P, whatever P may be. If, as can always happen, I discover I was wrong about P, then, as a matter of logic, I have to withdraw my statement that Joao knows that P. I can still say that Joao believes that P, but I can no longer say that he 'knows' because one of the requirements for knowledge (in the primary non-Cameron sense) is truth. I was wrong about what I thought Joao 'knew'. Sorry!

But what is truth? Don't we have to define that? If you look at contemporary literature on truth, you will see that there as a growing consensus on 'minimalism' (a kind of revamped 'redundancy' theory), which acknowledges just the sorts of points you make against coherence, correspondence and pragmatic theories. You can't 'define' truth in terms of check boxes or criteria, because all the boxes can be checked and the proposition in question turns out to be false after all. (The suspect was innocent, despite all the massive evidence pointing to his guilt.)

My short contribution to the StudyPartners forum (under an alias) made the point that, from a minimalist perspective, the term 'true' is just a device for propositional quantification. Using this, we can set out the requirements for knowledge without even mentioning the term 'true'. Whatever P is, if I claim that A knows that P, then my claim is refuted if P is refuted. That's the whole deal with 'knowledge' and 'truth'.

Against the 'Queen's speech' idea, we arguably need a term like 'know' (as contrasted with 'believe', which doesn't carry the truth implication), because we are interested in identifying persons who have authority to give out information about a particular topic. You consult someone who 'knows', not someone who merely has lucky guesses. (That's the bare bones of my 'theory of knowledge' for what it's worth.)

Personal identity

I'm not much into reading literature, but Proust's 'Remembrance of Times Past' is standardly quoted as an example of a situation where one can say, 'I remember saying 'I love you', but I am not the person who made that vow to you.' This is a point about the criterion of psychological continuity. My capacity to access memories (such as 'my' vow) may be necessary, but it it is not sufficient for personal identity in the absence of an additional factor, which might be termed the 'act of self-identification'.

Consider the macho rugby player turned gay hairdresser. We can tell a story about a gay man who becomes a rugby player as a way of deflecting suspicion about his true leanings. Underneath, he was always the same. He still thinks fondly about the prop forward he had a crush on all those years ago. In this story, there is not only continuity of memory but also self-identification.

On the other hand, with very few adjustments to the story we can imagine the gay hairdresser resolutely refusing to identify with the rugby player. 'That wasn't me, it was another person.' The hairdresser still 'remembers' the rugby games, but as it were from a distanced, almost third-person perspective. They are not 'his' memories.

This is a variant of Butler's objection to the Lockean theory of personal identity, to the effect that Locke's psychological definition 'presupposes' identity rather than defining it. The memories in question must be *my* memories. But given that we are seeking a definition of 'me' or 'I' the requirement seems patently circular.

You can combine the psychological criterion with a requirement of physical continuity of 'something' (say, states of the brain) that is causally necessary and sufficient for memory. In this way we can distinguish between 'true' and 'false' memories (e.g. the lunatic who seems to recall things that only Napoleon could have known) or deflect the ridiculous claims of people who supposedly 'remember' their past lives under hypnosis.

The resulting theory still leaves open the possibility of amoeba-like splitting, and it also fails to deal with the self-identification problem (although this is a murky area, and potentially open to abuse -- e.g. the convicted mass murderer asking to be released on the grounds tha he is now a 'different person').

There's no definitive answer. You can save logic (e.g. in the case of iterated amoeba-like splitting) if you are prepared, e.g., to hang a hundred men for a single murder (because each of them 'is' the person who committed the crime). Primitive or not, our views are largely held in place by mere contingency, the brute fact that these science-fiction possibilities are not realized in the real world.

All the best,