This result could have been achieved either by his [God] endowing my intellect with a clear and distinct perception of everything about which I would ever deliberate, or simply by impressing the following rule so firmly upon my memory that I could never forget it: I should never judge anything that I do not clearly and distinctly understand.
Rene DescartesIt must not be thought that it is ever possible to reach the interior earth by any perseverance in mining: both because the exterior earth is too thick, in comparison with human strength; and especially because of the intermediate waters, which would gush forth with greater impetus, the deeper the place in which their veins were first opened; and which would drown all miners.
Rene DescartesAn optimist may see a light where there is none, but why must the pessimist always run to blow it out?
Rene DescartesDivide each difficulty into as many parts as is feasible and necessary to resolve it.
Rene Descartes