' Many times the things that me had seemed true when I started to conceive they had become them false when it wanted to place them on papel.' ' (Discardings) First Meditation: Of the things that if can for in doubt. 1 the 6 Toma the resolution of for in doubt all the opinions received since infancy, to be able, since the beddings, to establish something of firm and constant in sciences, and not to take false as the true one. The function of the doubt is to destroy all its old opinions (if these to excite any doubt): systematic and generalized hyperbolic doubt. It goes to dedicate its company to the principles that base its old opinions. Felt: conceived until then as the safest knowledge, however these already had deceived it some time, therefore they must be placed in doubt. Dreams: had to its contents, to a great extent, Reals, what it occurs in the dreams, then, it is not very different of what it occurs when is awaken. The things represented in real and true the dreams they are analogy of the painting: exactly that the painters if pledge in representing not-existing figures, as sereias, chimeras, they will not be something new, but one mixture of members of diverse animals; if to make something new, thing that nobody has seen, at least the colors with that it paints the picture will be real. 7 the 10 simple and composed Ideas: the composed ideas, differently of the simple ones, are passveis to have been imagined, therefore the simple ones are more universal, true and existing; sciences as the physics, astronomy, medicine, that depend on composed ideas, are more uncertain doubtful and of what the mathematical (arithmetical and geometry), that they deal with simple and general, independent ideas to exist or not in the nature and independent of any thing (2+3=5). fast shows great expertise in this.