In Defense of Hylas and Support of Locke
I wish to defend and support John Locke's "The Causal Theory of Perception" because it is a logical argument with many useful applications. Primarily, this argument allows us to make more objective judgments about the world we perceive - it allows us to more accurately see reality by telling us how to separate the object itself from our own opinions or qualitative value judgments about the object. However, just the fact that a particular theory is useful does not mean that the theory itself is correct, even though that might be the motive for trying to prove its correctness. Therefore, I must also address George Berkeley's argument, put forth by his character Philonous in Three Dialogues Between Hylas and Philonous, that "to exist is to be perceived."
To tackle Berkeley's argument, I will take Hylas and Philonous's Tree Argument. This is a nice variation on the common riddle of "If a tree falls in the middle of a forest, and no one is there to hear it, does it make a sound?" Philonous is trying to prove that everything that exists is perceived, and therefore exists only in the mind. If this is true, then nothing exists without the mind, and it is therefore pointless to distinguish between primary and secondary qualities as Locke does. Philonous challenges Hylas to conceive of any sensible object that exists without the mind. Hylas responds with the idea of a tree existing by itself, independent of, and unperceived by, any mind whatsoever. Philonous then points out that this is a contradiction - conceiving a thing that is unconceived. However, these two riddlers are failing to take into consideration one crucial element - time.
Now, I intend to prove that things can and do exist even though we do not perceive them. My argument rests on this presumption: It is possible for us to conceive things that do not exist and to conceive not to exist things that do exist, and that time allows us to see what really exists and what really does not exist, at the very least for some things. If we truly believe an object (for example, a chair) to exist, we will be able to see it, to touch it, to hear it's sound. We will be able to do all of the above until we have a reason to believe that it does not exist. Notice that I have included several different senses in this example, including the sense of touch. However well we might perceive this particular chair to exist, if it is not real, we will fall to the floor if we try to sit in it. That is because our action of sitting depends on the chair being solid and actually existing.
Now, let us imagine me walking from the patio of a friend's home into the den. I turn and face the house and walk towards the doorway, heading towards the nice comfortable sofa. Suddenly, I am knocked flat on my back. Looking up, I see the sun reflecting off a perfectly cleaned sliding glass door. Up until the moment I hit the glass, I had no idea that...