It is the mark of an educated mind to be able to entertain a thought without accepting it.
These writings were first inscribed during an era that was extremely wary of the effects of Philosophy on the morale of Athens. Socrates was famously executed on charges of Sophistry only a few years prior to Aristotle's philosophical career.
This is Aristotle's argument against ignorance caused by the fear of being corrupted by false or bad ideas. He argues that one can entertain any hypothetical without being morally effected by it.
All men by nature desire to know
This is essentially the warrant for his life's work. He argues that Philosophy is worth-while because it answers a question at the heart of the human experience. What is true and what is false. It's our natural design as evidenced by our logical mind.
Truth and falsity [will not] be present in the same way as in the previous case. In fact, as truth is not the same in these cases, so also being is not the same; but (a) truth or falsity is as follows--contact and assertion are truth... for it is not possible to be in error regarding the question what a thing is, save in an accidental sense.
This portion of argument establishes the core understanding of the Metaphysics, namely that the physical world is evidence of the non-physical, causal force. This is the force by which a thing is a certain way, and in the same manner, existence itself can be viewed as the predication of some reality that is not directly observable.
It is clear, then, that wisdom is knowledge having to do with certain principles and causes. But now, since it is this knowledge that we are seeking, we must consider the following point: Of what kind of principles and of what kind of causes is wisdom the knowledge?
This passage makes use of logic that shows Aristotle's fundamental understanding, that knowledge can be used to infer causal truths about it. (Induction)