The author was prepared to go to any lengths in his search for certainty - even to deny those things that seemed most self-evident. In this book, he developed a language of subjectivity that has lasted, and he also took his first steps towards the view that would eventually be expressed in epigram "Cogito, ergo sum" ("I think, therefore I am"). Rene Descartes Meditations & Other Metaphysical Writings Paperback Book