The first and most necessary part of philosophy is practical principles; for example: don’t lie. The second part is proofs, as of why we shouldn’t lie. The third, which validates the other two, is logical theory, answering such questions as, how do we know that this is a valid proof? What is a logical demonstration? What does it mean when we say something follows something else? What is contradiction? What is truth? What is falsehood? The third part of philosophy is necessary for the sake of the second, and the second for the sake of the first. But the most necessary part, where we should linger, is the first. Of course we do exactly the opposite. We spend our time on the third part, becoming enthusiasts in that, and utterly neglect the first. So we lie through our teeth, but we certainly can demonstrate why one shouldn’t lie.