Metaphysics - Ch. 3

(Originally written July 23, 2006 in Book 6)

Metaphysics - Peter van Inwagen

Chapter 3 - Externality

Individual things exist outside of a mind.

Why is it not obvious that an external world exists?

One cannot be mistaken of what one is feeling or what one is presently thinking about. Both thoughts and feelings are of the mind. Feelings or thoughts are either individual things or modifications of individual things. Since they are not physical, but mental, if they are in fact modifications, they must be modifications of a mental individual thing. Thus, if individual things exist, at least one of them must be mental.

Berkeley believed in individual things, but that all individual things were mental. He held that all one senses are properties (color, shape, texture, taste) and properties belong to the mind. Thus, all things with properties belong to the mind. Berkeley asked if there is an external world, how can we know anything of it?

Most people will grant that color is mental, but will balk at the notion that shape is mental.

Berkeley argues that there are two kinds of shape: visual and tactile. Visual shapes exist without tactile shapes when one sees a shape but does not touch it. Tactile shapes exist when one touches a shape but does not see it. Visual shapes and tactile shapes are not the same property and neither can exist independently of the mind. The actual shape (combination of the two) is therefore illusionary. Thus, if something could exist independently of the mind it couldn't have properties of shape or color.

Berkeley instead that since we cannot know anything of the external world we cannot believe it exists either. If we do believe in it we would have to become thorough skeptics and admit that we have no valid reason for believing the external world exists.

Solipsists believe that the source of our sensations come from within us, but Berkeley does not believe this. If our sensations do not come from inside us (our sensations being our experiences and how we experience them) where do they come from? Common Western Metaphysics holds that experiences and how we interact with them (producing sensations) come from the external world. Berkeley holds that these experiences do come from a mind, but not our own. All things that are seemingly a part of the physical world are actually the product of the mind of God. God, like all humans, is an independent mind, but He is the Supreme Mind. God created all other minds and thus they are modifications. The senses are modifications of the mind. God coordinates all individual minds' senses to fit together like a big jigsaw puzzle. Thus, when two people look at the same object their perception is very similar (though not identical). Berkeley states this is how God created "all the furniture of the earth", the thing we perceive as the physical world. "He [God] carefully coordinates the sensations that come to all human minds in such a way that a common world is available to these minds" (van Inwagen, 47).

Linehan - I like this, but it makes me wonder about sin, evil and Evil.

Berkeley does not claim that God created an illusionary world though. He believes that in God creating minds and properties for the minds to perceive He created things that really exist.

A critic of Berkeley once wrote a limerick poking fun at Berkeley's theory. (I had heard this before, but not the response. I understood why it did not really do anything other than misrepresent Berkeley's theory, but like the response a lot).

Msgr. Ronald Knox:
"There was once a man who said, 'God
must think it exceedingly odd
if he finds that this tree
continues to be
when there's no one about it in the Quad"

Basically Knox said if all things are mental and no mind is 'physically' there to perceive it then it would cease to exist. Knox (as do most men) thinks that this would be absurd. But Berkeley argued that the Supreme Mind (God) perceived all 'physical' things at all times. Thus, even when a human mind is not present to perceive the individual tree, it remains, as an object of the mind, specifically the mind of God. Here is the response by an anonymous writer to Ronald Knox.

"Dear Sir,

Your astonishment's odd
I am always in the Quad
And that's why the tree
will continue to be
since observed by
Yours faithfully,

God

Linehan - Brilliant! (Bad beer commercial reference)

An idealist has not choice but to believe in a supreme being since a supreme mind is needed to sustain mental existence (which is all that exists).

Theism is the belief in the Supreme Being.

Externalism is the belief in a physical world, independent of minds.

Realism is the belief that the physical world is what causes our sensations.

Realism is a more plausible option because it requires a simpler explanation.

Occam's Razor was created by William of Ockham. It states basically that if theories compete for acceptance and give full account of all evidence then the theory that requires less speculation should be accepted over the theory that requires more speculation. If Occam's razor suggests that we should accept realism over idealism, why then would anyone accept idealism?

Berkeley claims that we all have minds and we all know our own mind. He claims that to hold to externalism, a belief in things other than the mind, is actually more speculative then to believe in only the existence of minds.

Why?

Well, we all have a mind, so to believe that others have minds that work in a similar way is not much of a stretch. Also, even though God, the Supreme Mind, is much more than our own mind it is nonetheless a mind and to believe it operates in a similar fashion is not much of a stretch. But to believe in the existence of an external world (something minds have no experience of) is more speculative then only believing in minds. Thus, by Occam's razor, Berkeley asserts idealism over realism.

Linehan - I don't know enough about Occam's razor to make a judgment, but the little I do understand of it leads me to question it. Should we always accept a simpler judgment? Yes, in some cases it is better to accept the 'plain' answer, but I don't believe that the razor should be an unquestionable universal procedure.

Van Inwagen argues that Berkeley bases his theory on two very doubtful assumptions:
1) A common object is nothing more than (or nothing apart from) its sensible properties
2) The sensible properties of common objects are the same things as the sensations we have when we see or touch (or hear or taste or smell) common objects

The common western metaphysic believes that properties exists so that they can be 'had' by something. To define an object by its properties and then state that once the list of properties have been exhausted there is nothing left and thus only properties exist is playing word games.

A thing must exist in order for properties to be, according to the common western metaphysic.

Also properties that exist in the mind are different than properties that exist as a feature of the object.

A person experiences a property when one comes into contact with a thing that contains a correlating property. (We experience whiteness when we experience paper, which is white)

Before studying metaphysics we believe in an external world and external objects because it appears to be true. Idealism does not seem to be true to us and in fact, seems to be false. Berkeley has not produced any good reason to accept idealism. Thus, it is best for us to accept realism.

"It may be that the idealists have a better cans than the one I have attributed to them. Students of metaphysics are hereby encouraged to investigate this possibility for themselves" (van Inwagen, 55).

Linehan - challenge?