Discourse on the Method of Rightly Conducting One's Reason and of Seeking Truth in the Sciences

by René Descartes

except our own thoughts, there is nothing absolutely in our power;

For how do we know that the thoughts which occur in dreaming are false rather than those other which we experience when awake,

For it is highly deserving of remark, that there are no men so dull and stupid, not even idiots, as to be incapable of joining together different words, and thereby constructing a declaration by which to make their thoughts understood;