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Descartes 2

Knowledge of Physical Objects

On Pg. 10 Descartes turns to his knowledge of physical objects. Refering to his meditations on thinking he says: "From this, I begin to learn a little about what I am.
Do I know physical objects more distinctly than I know the I?
But I still can't stop thinking that I apprehend physical objects, which I picture in mental images and examine with my senses, much more distinctly than I know this unfamiliar "I," of which I cannot form a mental image." So, Descartes is going to investigate this claim that one apprehends physical objects more distinctly than one does the "I." He is going to reject this claim. His investigation is the third application of the methods of doubt and analysis. This application, like the first two, will also yield certain truths which will make up part of the secure foundations of the house of knowledge.

Here is a point where we can think again about reading effectively, reading as a good philosopher does. If Descartes is applying his method again, and having gone through it twice before, we understand how that method works, we should be able predict what is coming. First we will start with the senses. If this investigation follows the pattern of the earlier ones, we shall find Descartes giving reasons why the senses do not give us distinct knowledge of the physical objects. After that, we should move to the level of the imagination. This level will also prove inadquate for giving us knowledge of physical objects. Finally we will reach the claims of reason reason which will yield certain and indubitable truths about physical objects. Isn't that how it should go? Let's see what happens.

In considering physical objects, Descartes decides not to consider the nature of physical objects in general "...since general conceptions are very often confused." Rather, Descartes takes one particular object which he sees and touches -- a piece of wax. Of this piece of wax Descartes says: "It has just been taken from the honeycomb; it hasn't yet completly lost the taste of honey; it still smells of the flowers from which it was gathered; its color, shape and size are obvious; it is hard, cold and easy to touch; it makes a sound when rapped." (Pg. 10) He remarks, "In short, everything seems to be present in the wax which is required for me to know it as distinctily as possible." So, just as we predicted, we are starting with the senses.

Descartes goes on to note how all the qualities which seem so distinct in the wax vanish! "But as I speak, I move the wax towards the fire; it loses what was left of its taste; it gives up its smell; it changes color; it loses its shape, it gets bigger; it melts; it heats up; it becomes difficult to touch; it no longer makes a sound when struck." Thus, all the properties which the wax seemed so distinctly to possess are gone! "Is it still the same piece of wax?" Descartes asks, and answers: "We must say that it is, no one denies it or thinks otherwise.
Sensible properties are not essential.
The implications of this experiment are that all of those properties which were so distinctly perceived by the senses are not essential to the wax (Remember "essential" means a property which is necesary for the continued existence of the thing which has it.) -- for they being gone the wax remains! So, if knowing means grasping the essence of something, the senses do not give us knowledge of physical objects! So, our second prediction has come true -- Descartes shows how the senses are inadequate as a basis for knowledge of physical objects! This is a good indication that we understand Descartes' thinking.

Does Descartes now proceed to consider physical objects as objects of the imagination? He does indeed. He says:

    Perhaps what I distinctly knew was neither the sweetness of honey, nor the fragrance of flowers, not a sound, but a physical object which appeared to me one way but now appears differently. But what exactly is it of which I now have a mental image? Let's pay careful attention, remove everything which does not belong to the wax and see what is left. Nothing is left except an extended, flexible and changeable thing.
Note the reference to mental images. Descartes goes on to argue that "my comprehension of the wax's flexibility and changeability cannot have been produced by my ability to have mental images." (Pg. 11) The imagination, then, is not adequate to give us knowledge of physical objects. Another successful prediction! (What would happen if our prediction turned out to be false? Well, we would most likely be forced to discover some new aspect of Descartes' thought which we had not yet grasped, which would explain why our prediction failed. So, when you use this technique of making a prediction about what a writer will say, you win whether you prediction turns out to be right or not. Either way, it helps you understand the text!)

Since one does not know about the wax by either the senses or the imagination, what is left but reason? Descartes says:

I must therefore admit that I do not have an image of what the wax is -- that I grasp what it is with only my mind...What then is this piece of wax that I grasp only with my mind? It is something I see, feel and mentally picture -- exactly what I believed it to be at the outset. But it must be noted that, despite the appearances, my grasp of the wax is not visual, tactile, or pictoral. Rather, my grasp of the wax is the result of a purely mental inspection, which can be imperfect and confused, as it once was, or clear and distinct, as it is now, depending on how much attention I pay to the things of which the wax consists.
So, the senses give us an imperfect and confused set of ideas of the wax which represent accidental properties (these are properties which a thing can gain or lose without ceasing to exist). Only the understanding, reason gives us clear and distinct ideas of the essential properties of the wax. Notice this language of clarity and distinctness versus confusion and imperfection. We will be hearing more about this when Descartes tries to figure out the criterion for certain knowledge. At this point, me might simply note that the third application of the method of doubt has proceeded just in the way in which we predicted it would! The result is that Desartes holds that it is just as difficult to know physical objects as it is to know the "I" In both cases one starts with what one unreflectively thought and then discovers using the methods of doubt and analysis that to clearly and distinctly grasp the essence of both the self and physical objects one must descend to the level of reason understanding and mind.

At the end of Meditation II, Descartes has discovered three indubitable truths which will serve as elements in the secure foundation on which the edifice of knowledge will be constructed. Are there only three thruths in the foundation, or are there more? In Meditation III Descartes says: "I now will examine more carefully whether there are other things in me which I have not yet discovered." (Pg. 14) As it turns out, he finds that there are more, indeed many more, truths which are part of the foundation. But before we get to those we need to consider Descartes' criterion for certainty at the beginning of Meditation III.


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