Friday, September 27, 2013

Leibniz on necessary and contingent truths

To: Scott B.
From: Geoffrey Klempner
Subject: Leibniz on necessary and contingent truths
Date: 23rd November 2010 12:16

Dear Scott,

Thank you for your email of 15 November, with your essay for the University of London BA module Modern Philosophy: Spinoza, Leibniz, Kant module in response to the question, 'Does Leibniz's account of truth allow for contingent as well as necessary propositions?'

I fully sympathize with your difficulties regarding the understanding and interpretation of Leibniz's philosophy.

It is relatively easy to answer the question: Yes, if you are prepared to make the required concessions, Leibniz's theory of truth does allow for contingent as well as necessary propositions. A proposition is necessary if it is true in all possible worlds. A proposition is contingently true if it is true in the actual world but not in other possible worlds. An actual world is fully determined by the individuals which comprise it. Any alteration in an individual would give rise to a different possible world. So it follows that a statement which is contingently true about, say, SB, consists in the attribution of a predicate to the subject, SB, whose individual concept 'contains' that predicate.

This is a weird notion of 'contingent truth'. Our pre-philosophical understanding of the nature of a statement about an individual is that any given predicate contingently might, or might not apply to that given individual. Philosophers distinguish between 'essential' properties like being human from 'accidental' properties like being a philosophy student, although intuitions about this are vague. For all I know, SB might be an intelligent android created by aliens in order to investigate Earth people. In this case, it would be quite plausible to say that if this turned out to be the case, I didn't 'really know' SB. It would be very odd to say that I know who SB *is*, but it is still logically possible that SB is an android and not a human. However, we find it utterly bizarre to claim that someone who doesn't know what marks SB will gain for his Modern Philosophy: Spinoza etc. module doesn't know 'who SB is'.

So, even if we accept that Leibniz's account of truth 'allows' for a distinction between contingent and necessary propositions, in his terms, it remains the case that Leibniz's notion of what a 'contingent proposition' is, is one that we find difficult to believe, to say the least.

The real question, is *why* did he hold this view?

This is where Leibniz leads students of his philosophy on a merry dance. Your essay contains a number of claims to the effect that Leibniz held A because he held B, and held B because he held C; but what really comes first in an explanation of the process of reasoning which leads to the claim about necessary and contingent propositions?

Russell thought he knew. In his book on the philosophy of Leibniz, Russell argued that the key to Leibniz's philosophy, and in particular to his view about the nature of individuals lay in his inability to see any alternative analysis to the Subject-Predicate form. At the time when Russell was writing, the idea that there could be relational truths was something radical. Previous philosophers had failed to grasp the point that Russell saw, that relational truths can be primitive, not analysable into non-relational propositions. Leibniz merely saw with greater clarity the consequences of failure to admit relational truths. Leibniz is an object lesson in what happens if you fail to give a correct analysis of relational propositions.

I don't believe that diagnosis, and I don't think there are many commentators on Leibniz who would agree with Russell today. So the hunt is on to find a better explanation.

I think that the explanation starts with Leibniz's account of the nature of space, and his response to Cartesianism. Like Berkeley, Leibniz was sceptical about the idea of an all-powerful being who might, or might not create a world of matter in space corresponding to our experience depending on whether or not he was sufficiently benevolent not to allow us to be 'deceived'. From Berkeley's point of view, there is no 'deception'. When we look out onto the world we are looking at the inside of God's mind. The things we call 'material objects' are merely 'ideas'. Leibniz proposes a different, more robust account of the nature of existence. Every object has its 'point of view' on the world. Add up all the points of view and there *is* nothing else, no empty 'space' for objects to exist 'in', as Newton (and Descartes) believed.

We can state this in terms of what God chose to create, but God doesn't really play such an important role (at least, not as important a role as He plays for Berkeley). In order to create the object SB, God had to create the universe as seen from SB's point of view. SB doesn't have this knowledge (as you state), the reason being that his perceptions are more or less 'confused'. However, when you describe all the points of view -- of entities which we term 'non-sentient' as well as those we term sentient or intelligent -- you have described the universe.

Leibniz's metaphysics was taken up by the academic philosopher Wolff, and it was Wolff's metaphysical system that Kant lectured on. From Kant's viewpoint, Leibniz's theory of monads was an attempt to state, in terms of 'experience' truths the nature of which go beyond the bounds of possible experience. His 'monads' are Kant's 'things in themselves' or 'noumena', the ultimate constituents of the universe of which we can form no positive conception for the very reason that they transcend the bounds of possible experience.

All the best,