Descartes had no doubt that human beings know some things and are capable of discovering others, including (at least since his metaphysical insights of 1629) fundamental truths about the basic structure of reality. Yet he also believed that the philosophical methods taught in the schools of his time and used by most of his contemporaries were deeply flawed. He believed that the doctrines of scholastic Aristotelian philosophy contained a basic error about the manner in which fundamental truths, such as the truths of metaphysics, are to be gained. He expressed this mistaken view in the First Meditation, by saying (not in his own voice, but in a voice for the reader): “Whatever I have up till now accepted as most true I have acquired either from the senses or through the senses” (7:18). He then went on to challenge the veridicality of the senses with the skeptical arguments of First Meditation, including arguments from previous errors, the dream argument, and the argument from a deceptive God or an evil deceiver.