Six Metaphysical Meditations

The idea Descartes summed up elsewhere as 'I think, therefore I am' is reached here by a famous path. He resolves to doubt everything that can possibly be doubted: his senses, which sometimes deceive him; whether he is awake or dreaming; even mathematics, since an evil demon might be deceiving him. One thing survives the doubt: while he doubts, he must exist as a thinking thing. From this foundation he argues for the existence of God, the distinction between mind and body, and the reality of the material world.

René Descartes (1596–1650) published the Meditations in Latin in 1641, together with objections from other philosophers and his replies. This is the first English translation, by William Molyneux, printed in London in 1680, and it includes the objections of Thomas Hobbes, the author of Leviathan, with Descartes's answers. Read Descartes's Discourse on the Method.

René Descartes (1596–1650) was educated by the Jesuits, served as a gentleman soldier, and on a winter night in 1619, shut in a stove-heated room in Germany, had the series of dreams that convinced him to rebuild all knowledge from scratch. He spent most of his adult life in the Netherlands, where he could work in peace.

His Discourse on the Method and Meditations made 'I think, therefore I am' the starting point of modern philosophy, and his invention of coordinate geometry joined algebra and geometry for good. Invited to Stockholm by Queen Christina, who wanted lessons at five in the morning, he caught pneumonia and died there in the winter of 1650.