So, in the last meditation we reached a dead-end. Descartes decided that everything that was taken for granted to be true is not any less false than the myth of Santa Claus. The corporal nature of the world was no longer evident and clear as it once seemed to be. Maybe there's some kind of god or devil making it about that there's no heavens, no earth, no fire, no light, no hands, no eyes, no world and yet he also managed to bring it about that we experience these things. So, the only knowledge that Descartes now has is that nothing is certain. Let's go back to the purpose of the meditations. It was to try to find something so certain that's not subject to any kind of doubts. Something that's unshakeable on which we can construct our ideas. To be able to do so, we decided to reject any idea that is subject to the least kind of doubt. We cast such ideas completely false for now until we find a solid and firm ground.
Therefore I suppose that everything I see is false. I believe that none of what my deceitful memory represents ever existed. I have no senses whatever. Body, shape, extension, movement, and place are all chimeras. What then will be true? Perhaps just the single fact that nothing is certain
But on the course of doubting everything, and considering every experience we have as nothing but an illusory dream casted on us by some deceitful god, we run into the fact that we are something, that we exist. You might say this might be another trick of this god, but no. If god is actually deceiving us, then we surely exist, for something must exist in the first place for it to be deceived. But if god is not deceiving us, then we justfiy the fact that we exist simply by observing that the same very thing that doubts and thinks it's something must exist. Therefore, the famous "I am, I exist".
But doubtless I did exist, if I persuaded myself of something. But there is some deceiver or other who is supremely powerful and supremely sly and who is always deliberately deceiving me. Then too there is no doubt that I exist, if he is deceiving me. And let him do his best at deception, he will never bring it about that I am nothing so long as I shall think that I am something. Thus, after everything has been most carefully weighed, it must finally be established that this pronouncement "I am, I exist" is necessarily true every time I utter it or conceive it in my mind.
That's actually really good. Now, we have something we are 100% sure it's true and indubitable. That I, We, exist. Now the next question to ask is what is I or We. Who am I ? Well, I know that I am a human. But the notion of a human belongs to the corporal world and we already decided that any idea that belongs to it is false. For we will then ask what a human is, sliding into a series of harder questions that we are not equipped well enough to answer. What am I then? we already affirmed our existence by the fact that we doubt and think. It's only natural for now to attribute to us the property of thinking: We are thinking things.
At this time I admit nothing that is not necessarily true. I am therefore precisely nothing but a thinking thing; that is, a mind, or intellect, or understanding, or reason—words of whose meanings I was previously ignorant. Yet I am a true thing and am truly existing; but what kind of thing? I have said it already: a thinking thing.
Descartes then moves on to discuss sensing. We already refused to believe in sensing since we know that the corporal reality is not true. But isn't sensing another aspect of thinking? when we seem to see something, it's actually the process of thinking in the brain that makes us percieve it and not the sense itself. So, sensing is just another aspect of sensing. Am I then a thing that thinks and senses? So far, I am something that only thinks since sensing is just another aspect of thinking:
Finally, it is this same "I" who senses or who is cognizant of bodily things as if through the senses. For example, I now see a light, I hear a noise, I feel heat. These things are false, since I am asleep. Yet I certainly do seem to see, hear, and feel warmth. This cannot be false. Properly speaking, this is what in me is called "sensing." But this, precisely so taken, is nothing other than thinking.
Can we really claim that we know the mind better than anything else?
At this point it seems that we know the corporal world better than our mind. You seem to perceive a tree, light, fire, and buildings better than we have a good grasp of our mind. Do we actually? We will consider a modified version of a wax argument by Descartes. You are in the kitchen, drinking a cup of iced juice. Consider the ice cube. It's transparent; solid; has no color; no smell; your hands get cold when you touch it. Now you go to make a cup of tea. You fill the pot with water. Now it has changed state and it's liquid. After heating the water, some of it changes form again an turns into vapor. But no one can deny that it's still water even though it changed form and "its sensory experience" changed. Therefore we seeom to perceive the water no through the senses but through intellect. Definitely we cann see, smell, tase, and feel the water, but what makes us percieve it as such, water, is the intellect even after changing its attributes. Descartes then concludes with saying that we are thinking beings, and we know our mind better than anything else:
But lo and behold, I have returned on my own to where I wanted to be. For since I now know that even bodies are not, properly speaking, perceived by the senses or by the faculty of imagination, but by the intellect alone, and that they are not perceived through their being touched or seen, but only through their being understood, I manifestly know that nothing can be perceived more easily and more evidently than my own mind. But since the tendency to hang on to long-held beliefs cannot be put aside so quickly, I want to stop here, so that by the length of my meditation this new knowledge may be more deeply impressed upon my memory.