Tag Archives: Hume

Plato’s Dialectic

Plato held that in philosophy, we arrive at the truth by means of a process of “dialectic.” Dialectic, for Plato, works as follows:

  • We begin by having one person put forward an answer to the problem in question on the basis of certain arguments.
  • Another person then comes along, points out flaws in the first person’s answer, and puts forward his own answer.
  • Then a third person comes along, criticizes both viewpoints, and puts forward an answer that is better than either of them.
  • etc.

Plato held that, over time, this process leads us closer and closer to the truth. This is illustrated by some of his dialogues.

Plato’s theory assumes that we have a way of rationally evaluating an answer to a philosophical question as plausible or implausible. Plato held that we could see this “intuitively,” but his account of intuition depends on his metaphysics, which most philosophers have rejected.

Another perspective on dialectic comes from David Hume. Hume agrees that it often happens in philosophy that one person puts a position forward, and then another person criticizes it and puts their own position forward. However, according to Hume, the intuitions that this process depends on are subjective products of “habit or custom.” So, while dialectic can arrive at conclusions that better appeal to a given person subjectively, it is not a source of objective truth like Plato thought.

I think the only way to answer Hume once and for all is to present a body of demonstrably true conclusions in philosophy. So long as philosophy is seen as an endless debate, many will be inclined to question whether it has any cognitive status at all. There have been a number of attempts to do this since Hume, and evaluating all of them is beyond my scope here.

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Rationalism vs. Empiricism

The Stanford Encyclopedia of Philosophy has a great article explaining the basics of the rationalism – empiricism debate. It covers Descartes, Leibniz, Locke, Hume, and some contemporary thinkers. Kant is mentioned but not really discussed.

http://plato.stanford.edu/entries/rationalism-empiricism/

My position is closer to the empiricism side of things, if we go by the terminology of this article. I don’t think we gain any knowledge solely on the basis of deduction from a priori intuitions, although I think deduction plays an important role in knowledge, and I don’t think we have any innate knowledge or innate concepts.

Of course, there is a lot of work that needs to be done to establish this position, and I’m not going to attempt that here.

 

My Objections to Hume

I posted the following in response to a request for my thoughts on Hume:

My main two objections to Hume are his view of induction and his view of morality.

I don’t agree that inductive inferences are merely a matter of habit – we do perceive causality, although we perceive it originally in specific instances and then abstract the concept of causality from those instances. Causality isn’t immediately perceivable like the color red is, but we can learn of its existence by inference from things like pushing a ball and watching it roll, and scientific theories are broader generalizations induced from numerous directly perceivable causal connections like this.

I also don’t agree that morality is a matter of the sentiments rather than of relationships between things. We do originally become aware of moral distinctions by means of the sentiments – I don’t like being hurt, so I conclude that that’s bad, and I like having friends, so I conclude that that’s good. However, there is an objective moral standard that we can infer from these primitive moral beliefs, based on a specific kind of life that it is best for a human being to have, one centered on our own self interest.

So basically, I think Aristotle has better positions on these issues than Hume does. I might do a longer post on Hume later.

Descartes, Spinoza, and Hume on Free Will

I’ve been reading a lot of early modern philosophy recently, so here are a few different perspectives on free will from that era. Descartes was a libertarian, Spinoza was a hard determinist, and Hume was a compatibilist.

Descartes was, famously, a substance dualist, which meant that he thought that the mind was actually an immaterial thing distinct from the brain. He thought that it was self evident that we have libertarian free will, conceived as the ability to affirm, deny or suspend judgment about a proposition that has been put before us and as the ability to choose what actions we perform. Descartes also thought that all of the actions that occur in the physical world are completely determined by the mechanistic laws of physics, which made it difficult to explain how the mind, which was immaterial and non-deterministic, could interact with and effect change upon the body, which was material and deterministic. His “solution” was that the soul exerts control over the body through the pineal gland, which is hardly a solution.

Spinoza was a little more consistent than Descartes. He was a panpsychist, meaning that he thought that everything physical was conscious in some degree. He actually thought that everything physical was identical to a conscious state, conceived under a different aspect. My mind and my body are just different ways of looking at the same thing, on this view. The body is governed by the laws of physics, which Spinoza claims reduce to a few self evident principles that we know a priori (he lays these out in the Ethics, and yes, they are all wrong), and the mind is governed by a different set of principles that always have the same results as the laws of physics. So for example, my belief that I am wearing a green shirt is identical to some physical state of my body, and my body is acting according to the laws of physics, and my mind is acting according to the laws governing states of consciousness, but both the laws of physics and the laws governing consciousness have the same result, namely that I currently have this belief.

Spinoza is not a substance dualist, because he thinks that the mind reduces to a bunch of different beliefs and desires that don’t have a common underlying substratum. There is no “self,” for Spinoza, just a bunch of different mental states. Further, Spinoza thinks that everything that happens is absolutely necessary, like it is necessary that 1+1=2. So, there is no question of our having free will, in Spinoza’s view, because there is no one to exercise the free will and even if there was, their decisions would be completely determined by the laws of physics and logic. The appearance that we have free will is an illusion created by our ignorance of our own mental processes.

This raises a problem for Spinoza that I mentioned in a previous post. Namely, if there is no self and everything we do is determined by the laws of physics, why should we trust any of the conclusions that we arrive at? Spinoza would address this concern, I think, by dissolving the distinction between truth and justification. He says at one point that “truth is its own criterion.” Spinoza thinks that if one of your beliefs is true, as opposed to arrived at by accident, then you have proved it by such a powerful a priori deductive argument that there is no way you can be wrong. So, the issue of justification doesn’t really come up for Spinoza, because there is no way of questioning the conclusion of an overwhelmingly powerful deductive argument like he requires for knowledge (although one might wonder whether we ever have knowledge that is this powerfully justified).

Hume’s conception of free will is based on his moral psychology. For Hume, as for Spinoza, the mind is a succession of beliefs and desires rather than a single, unitary entity. According to Hume, we act when a belief aligns with a desire. For example, I perform the action of going to the store because I want ice cream and I believe that there is ice cream at the store. This is a deterministic account of action, but Hume doesn’t see it as opposed to free will. Instead, he argues that free will consists in “liberty of spontaneity,” the ability to act without being coerced by an external force. Hume thinks that liberty of spontaneity is not only the only kind of free will we could possibly have, but also the only kind of free will that is consistent with the institution of moral responsibility.

I view my position on free will as distinct from any of these. I am a libertarian, like Descartes, and I agree with Descartes that libertarian free will is self evident, but unlike Descartes, I don’t view consciousness or free will as supernatural. Free will is not a puzzle to be explained by means of mysticism, but rather a normal part of the natural world that can in principle be studied and understood by science.