In my series on substances, I have begun exploring causation and how to properly understand it. I would like to step back a bit and explain about what explanation means. Explanation is either in general or of things. Explanation is general satisfies two criteria: it is logical and it is sufficient.

The first criterion of explanation is that explanation is logical. This means that it is not contradictory. No explanation both affirms and denies the same thing at the same time and in the same sense. So if we know that proposed explanation is about the same thing, means the same thing but says that it is both true and false at the same time, then that explanation is wrong. There are no exceptions to this rule. Although it is not possible to prove that contradictions are false, we all recognize that they are false. It is self-evident. We could even, if we wished, demonstrate that people really do believe that contradictions are false. This is true even if some people believe that some contradictions are true. Those people do not really believe this. They just claim to believe it.

The second criterion of explanation is that all explanations are sufficient. A sufficient explanation is one in a reason is given for what you are explaining and that reason is sufficient. A reason must be given for the existence of what is being explained. If what is being explained is a change, then that change can be understood as either the beginning of an existence or the end of an existence. So a sufficient reason is one that explains why something exists. There are two distinctions though. First, it need not explain why something exists rather than nothing. Such a question is meaningless in the general case. In particular cases, the relevant alternatives may not be nothing. Second, it need not explain why something does not exist. If we consider the case of something that does not exist, it cannot cause something to exist. So something that does not exist can not explain something that does exist. So if something exists no longer, the explanation can only be found in what does exist. If we ask why the thing that no longer exists did exist, then that will give us the reason.

It is not possible to prove the criterion of explanation any more than it is possible to prove logic. Any proof that was used to prove the criterion of explanation would rely on premises. These premises would explain – given the proof – why the conclusion follows. But such a proof could not use any explanation without assuming that the explanation used is correct. Since the criterion of explanation are the most general that they could be, any and all proofs use them. Therefore, any proof for the criterion would assume that the criterion was correct. Therefore, no proof of the criterion is possible. Like logic, the best we can do is point out that the criterion is self-evident. Anyone who examines it carefully enough will discover that it is correct.

I will save such an examination of that principle for another time. Next, I will discuss explanation as is applies to explaining things.