Rene Descartes...on the light of reason

Hence we must believe that all the sciences are so interconnected , that it is much easier to study them all together than to isolate one from all the others. Therefore, if anyone wishes to search out the truth of things in earnest , he should not select any one special science; for all the sciences are conjoined with each other and interdependent. Let him think only about how to increase the natural light of reason, not in order to solve this or that difficulty of a scholastic nature, but that his understanding may direct his will to its proper choice in every contingency of life.

- Regulae ad Directionem In genii, 1629