Meditations I and II

Meditations I and II are part and parcel to Ren� Descartes' larger work, "Meditations on First Philosophy." The First Meditation, subtitled "What can be called into doubt", opens with the Meditator reflecting on the number of falsehoods he has believed during his life and on the subsequent faultiness of the body of knowledge he has built up from these falsehoods. He has resolved to sweep away all he thinks he knows and to start again from the foundations, building up his knowledge once more on more certain grounds. He has seated himself alone, by the fire, free of all worries so that he can demolish his former opinions with care.The Meditator reasons that he need only find some reason to doubt his present opinions in order to prompt him to seek sturdier foundations for knowledge. Rather than doubt every one of his opinions individually, he reasons that he might cast them all into doubt if he can doubt the foundations and basic principles on which the opinions are founded.Everything that the Meditator has accepted as most true he has come to learn from or through his senses. He acknowledges that sometimes the senses can deceive, but only with respect to objects that are very small or far away, and that our sensory knowledge on the whole is quite sturdy. The Meditator acknowledges that insane people might be more deceived, but that he is clearly not one of them and needn't worry himself about that.However, the Meditator realizes that he is often convinced when he is dreaming that he is sensing real objects. He feels certain that he is awake and sitting by the fire, but reflects that often he has dreamed this very sort of thing and been wholly convinced by it. Though his present sensations may be dream images, he suggests that even dream images are drawn from waking experience, much like paintings in that respect. Even when a painter creates an imaginary creature, like a mermaid, the composite parts are drawn from real things--women and fish, in the case of a mermaid. And even when a painter creates something entirely new, at least the colors in the painting are drawn from real experience. Thus, the Meditator concludes, though he can doubt composite things, he cannot doubt the simple and universal parts from which they are constructed like shape, quantity, size, time, etc. While we can doubt studies based on composite things, like medicine, astronomy, or physics, he concludes that we cannot doubt studies based on simple things, like arithmetic and geometry.