October 18, 2006

This Post is Old!

The post you are reading is years old and may not represent my current views. I started blogging around the time I first began to study philosophy, age 17. In my view, the point of philosophy is to expose our beliefs to rational scrutiny so we can revise them and get better beliefs that are more likely to be true. That's what I've been up to all these years, and this blog has been part of that process. For my latest thoughts, please see the front page.

Descartes, Berkeley, and Moore on the Existence of the Spiritual and the Physical

My apologies for the lack of posting. I've been very busy this semester. I do, however, have a moment tonight, and I have been thinking about Moore's argument for the existence of the physical world. I've been thinking about it in part because I actually read him for the first time a last month (although I was already somewhat familiar with his argument from reading Wittgenstein's On Certainty), and in part because a friend of mine recently (on my suggestion) made a remark about Berkeley in a contemporary philosophy class and was summarily dismissed with an argument almost identical to Moore's.

For those who may not be familiar, Moore's argument looks something like this:

  1. Here is one hand; here is another

  2. If there are two hands here, then two hands exist.

  3. Hands are physical objects

  4. Therefore, physical objects exist

This simple argument seems to be part of the reason why many contemporary analytic philosophers do not consider idealism a live issue (something that I intend to make it my business to change). However, it seems to me to have two enormous and equally simple defects:

  1. It isn't actually an objection to Berkeley's theory, since Berkeley accepts all of the premises and the conclusion.

  2. Most people who make this argument are physicalists but if you accept the argument then, by parity of reasoning, you must allow Descartes to prove the existence of the soul.

Concerning the first problem: Berkeley's famous maxim is esse est percipii; "to be is to be perceived." Moore thinks he proves the existence of an external world by showing us his two hands. In fact, this proves that the external world exists in precisely the way Berkeley says it does: it's esse is percipii. To speak more clearly, if the fact that I can see two hands is conclusive evidence that the two hands exist, then Berkeley's view is correct, and perception defines reality (at least for hands). If the existence of hands was mind-independent, then even though I could see Moore's hands, they might not exist.

However, there is a bit more to Moore's argument than this, and he may be able to level an objection at Berkeley after all. The real meat of what Moore is getting at is in the third premise: Moore and Berkeley do not agree on what it means for something to be a physical object. Moore thinks that physical objects have a mind-independent reality. His real argument here, though, is that he is more certain that his hands exist as mind-independent physical objects than he is of the premises of any skeptical or idealistic argument about the physical world. Therefore, he thinks, it is more reasonable to hold to the existence of hands, and therefore physical reality, than to bow to the skeptical arguments. This, however, is where he gets into trouble with Descartes.

Descartes' argument for the existence of his soul is in fact quite similar to Moore's argument for the existence of physical substance. Moore says "I am perceiving physical objects, therefore physical objects exist;" Descartes says "I am having a subjective experience of the world, therefore my soul exists." Both Descartes and Moore are making the same mistake: they are taking a phenomenological point and drawing from them conclusions about metaphysical substances which are not objects of experience. Moore has proven that physical substance exists and Descartes has proven that mind exists, but neither have proven it in the way he seems to think he has. Moore has observed that there are perceptions, and Descartes has observed that there are subjective experiences, and these do, in my view, show that body and mind, respectively, exist in the only way possible and the only way that is meaningful for human beings. However, neither show anything about whether mind or body are metaphysical entities, and whether they are on par ontological or whether one depends on the other. Descartes simply assumes that thinking things are immaterial substances, and Moore simply assumes that perceived things are mind-independent substances, and it seems to me that these statements have approximately equal degrees of justification: namely, none whatsoever.

Thus we can see that Moore's argument cannot possibly serve as a physicalist response to Berkeley. In his defense, Moore himself did not intend his argument to respond to idealists, but to skeptics, and as an argument against skepticism it fares somewhat better. Also in Moore's defense, he wrote a separate paper, "The Refutation of Idealism," which, as the name suggests, is targeted specifically at the idealist position. This paper is sitting on my bookshelf waiting to be read. In the meantime, I hope that this post will motivate some of you to consider Berkeley's positions if not seriously enough to accept them, at least seriously enough to attempt to provide a real argument against them.

Posted by Kenny at October 18, 2006 6:22 PM
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I don't have any problem with the main substance of this post, but I do want to quibble with what you say about the acceptance of Moore's argument. I don't think it's generally viewed as a good argument at all. Most philosophers take it to involve an equivocation. What you know as a hand in premise 2 is not the same thing that you conclude in premise 3 as a hand, which is basically your point. I think most philosophers recognize this.

I think the majority position on this nowadays is simply reliabilism. We know of the external world by perceiving it, but we can't prove that we know it and thus we can't know that we know it. Given that the external world exists and that our senses reliably report it to us, we know it. I sometimes wonder if Moore had something more like that in mind. One paper I've read by him sounds externalist in exactly that way, but at times he sounds much more internalist in a way that reliabilism would seem intolerable to him. Either way, this particular argument is not generally accepted by most philosophers I know. Those who defend it usually try to make him out to be doing something much more sophisticated than the argument appears to be doing on the surface.

Posted by: Jeremy Pierce at October 18, 2006 9:32 PM

Thanks, Jeremy. I'm increasingly noticing my deficiency in contemporary philosophy and trying to work on it. The reason for most contemporary analytic philosophers' dismissal of idealism is of great interest to me for reasons that are probably quite obvious right now, and I'm also interested in the reasons for his rejection by earlier analytic philosophers like Moore. In particular, I'm wondering how on earth the verificationists could possibly reject phenomenalism. But, again, I'm a little beyond my present knowledge on this.

I do think Moore's argument about his degree of certainty about his hands' existence vs. his degree of certainty about the premises of skeptical arguments is a good one, although I wanted to point out that Descartes (or whoever) can just as easily make a claim like this about the existence of the soul. In other words, it may well show epistemic warrant, but it doesn't show justification let alone truth.

Posted by: Kenny at October 18, 2006 10:34 PM

Actually, I think the main reason contemporary philosophers dismiss idealism is that they think it violates Ockham's Razor. You have to accept theism to make sense of it, and even if it's simpler to have ideas and minds than it is to have ideas, minds, and an external world, things aren't as straightforward as Berkeley thinks when one of those minds is God. Those who are already theists can't make that move, but I think that's behind most of the rejection of idealism.

I'm not aware of very many theists who defend idealism nowadays, and I'm not sure what the reason is there except some sort of reliabilism as defending the possibility of knowing of an external world. That, of course, isn't an argument for an external world, and thus it strikes me as insufficient as a reason to reject idealism. The only contemporay theist I know of who defends idealism is Robert Adams, whose work on early modern philosophy has led him to consider idealism as the best metaphysic. I don't think very many others even consider it as a real possibility, usually concluding that Berkeley's arguments are fallacious (as some are) without really grasping what he was up to.

Posted by: Jeremy Pierce at October 21, 2006 10:22 AM

References for contemporary epistemology:
�Bamboozled by Our Own Words�: Semantic Blindness
and Some Arguments Against Contextualism, Keith DeRose.
Epistemic Modals are Assessment Sensitive, Relativism and Disagreement, The Assessment Sensitivity of Knowledge Attributions,John Macfarlane.
Epistemic Modals in Context, Egan, Hawthorne, Weatherson.

Posted by: jeff dauer at November 19, 2006 10:38 AM

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