Answer:
Physics and Mathematics.
Step-by-step explanation:
In addition to his philosophical writings, Rene Descartes is famous for making discoveries in physics and mathematics.
Though Rene Descartes is famously regarded as the 'father of modern western philosophy', he has also immensely contributed in the field of physics and mathematics. Rene Descartes contribution towards the development of modern physics is that he provided the first clear modern design of laws of nature which were later studied along with Newton's law of motion.
On the context of mathematics, Rene Descartes provided an epic work called La Geometrie. It provides geometric explanation and methods of linear algebra, complex analysis, differential geometry, etc. He is also regarded as 'the father of analytic geometry.'