Although mathematical methods of investigation have been used to establish meaning and analyse the world since Pythagoras, it was Descartes who pioneered the subject as
epistemology, setting out
Rules for the Direction of the Mind. He proposed that method, rather than intuition, should direct the mind, saying: In the discussion of
Rule Four, Descartes' describes what he calls
mathesis universalis:{{quote| ; Rule Four ; We need a method if we are to investigate the truth of things. [...] I began my investigation by inquiring what exactly is generally meant by the term 'mathematics' and why it is that, in addition to arithmetic and geometry, sciences such as astronomy, music, optics, mechanics, among others, are called branches of mathematics. [...] This made me realize that there must be a general science which explains all the points that can be raised concerning order and measure irrespective of the subject-matter, and that this science should be termed
mathesis universalis — a venerable term with a well-established meaning — for it covers everything that entitles these other sciences to be called branches of mathematics. [...] The concept of mathesis universalis was, for Descartes, a universal science modeled on mathematics. It is this mathesis universalis that is referred to when writers speak of Descartes' mathematicism. Following Descartes, Leibniz attempted to derive connections between
mathematical logic,
algebra,
infinitesimal calculus,
combinatorics, and
universal characteristics in an incomplete treatise titled "
Mathesis Universalis", published in 1695. Following on from Leibniz,
Benedict de Spinoza and then various 20th century philosophers, including
Bertrand Russell,
Ludwig Wittgenstein, and
Rudolf Carnap have attempted to elaborate and develop Leibniz's work on mathematical logic, syntactic systems and their calculi and to resolve problems in the field of metaphysics. == Gottfried Leibniz ==