The extract forms the very beginning of Descartes’ projected treatise on the World, and it is noteworthy that he begins by preparing the reader for the idea that the images in our minds do not resemble their external causes. One of his examples is so close to Galileo’s in The Assayer that he may have plagiarised them.

The World, or Treatise on Light was first published in 1664, but from a faulty copy of the manuscript. Clerselier re-published it in 1677, using the original manuscript.

It was written in French, and my translation is from Adam and Tannery, Volume XI, to which the page numbers in square brackets refer.

Go to the Index to the Treatise on Light