  The “Nouveaux Essais” count as Leibniz’s main work in epistemology. They were written between 1703 and 1705 and contained criticism of John Locke’s An Essay Concerning Human Understanding (Locke 1690). Locke died in 1704 when Leibniz was still working on the essays. The text caused a great sensation when it was published by Raspe. It can therefore be regarded as a key text for the reception of Leibniz in the late 18th and the 19th century. Logical considerations can be found in the fourth book “De la connaissance”. They concentrate on the theory of syllogism, but all elements of Leibniz’s theory of logic are present, to the extent that they are regarded as a device for the evaluation of the validity of given theses (ars iudicandi) and for finding new truths on the basis of given truths (ars inveniendi).