Practical reason

You can understand why the medievals, with their earthy practicality, responded to Aristotle, who offers arguments like this one against the irrationalism of monism: If everything is and is not simultaeously, yh not walk over a cliff? “Why do we observe him guarding against this, evidently because he does not think that falling in is alike good and not good?”

If “he judges one thing to be better and another worse. And if this is so, he must also judge one thing to be a man and another to be not-a-man, one thing to be sweet and another to be not-sweet. For he does not aim at and judge all things alike, when, thinking it desirable to drink water or to see a man, he proceeds to aim at these things; yet he ought, if the same thing were alike a man and not-a-man.”

It’s evident that “all men make unqualified judgements, if not about all things, still about what is better and worse.” And thus they practically refute their own philosophical theories.