The whole point of the search for cartesian concepts is that you can reason with such definitions. They are the useful ones. The rest—well, it’s a swamp, logically speaking.
You’re mostly limited to such definitions when it comes to deductive reasoning; inductive and heuristic reasoning can work well with concepts that have sharp edges or lots of fuzziness.
You’re mostly limited to such definitions when it comes to deductive reasoning; inductive and heuristic reasoning can work well with concepts that have sharp edges or lots of fuzziness.