Are there any substantive first (i.e. self-evident) principles? Substantive meaning informative: neither tautology nor mere principles of formal logic.
Some argue that there are none, that there can be none: Any given principle is either substantive or self-evident (exclusive disjunct).
The reason given is that in order to be grasped as self-evident, the principle must be so close to the Principle of Contradiction that it is practically a repetition of this principle. All such propositions are easily grasped as being necessarily true, and just as equally uninformative.
Conversely, all statements that are truly informative require, to be understood and affirmed as true, some theoretical framework which renders the principles grasped only within the framework to be hypothetical. Every such proposition is open to possible falsification (or further ratification) as the inquiry continues. Hence, no such proposition could be affirmed to be necessarily true.
I maintain that the above disjunct is not absolute. I suggest the following two arguments demonstrate that it is not absolute. The first is that the affirmation that this disjunct is absolute requires in practice the denial of the truth of the disjunct. The second is that some there are in fact some substantive self-evident principles.
First: If it were true that there are no substantive self-evident principles, one could not affirm with certainty that there is none. This is shown impossible on the very terms of the disjunct.
This proposition itself – Any given principle is either substantive or self-evident – is informative. It is not a practical repetition of the Principle of Contradiction. Therefore, if it were true, no one could affirm it to be true necessarily. Instead, one would have to wait for its further verification, or falsification, in which case one could not lay it down apodictically. Or, conversely, if one grasped that it—an instance of an informative proposition—is necessarily true, one would demonstrate that it—there are no substantive self-evident principles—is false.
Second: There exist seemingly mundane, but to me marvelous, truths of the perennial philosophy which are both informative and necessarily true. For example: Every animal moves itself. Informative because motion and animal are not the same concept, for the living mind (not the computer) thinks the one thing in aspects (and does not merely bundle properties). For example: Every man is risible. Informative because laughing and man are not the same concept. However, in the concept man we have the distinct ideas of rational and animal. Who is rational but of limited intelligence can grasp what is in place and can be befuddled at what is out of place. Who is animal has lungs and a voice box. Thus, who is both rational and animal has wherewithal bodily to express befuddlement: Can laugh. These truths do not yield supercomputers. But they are instances of real insight into a real world. And the discovery of these truths is just that, progress and discovery. It is progress to grasp what “animal” is and what “rational” is. Insights into reality. It is progress to put these insights together rationally. It is progress to come to a conclusion. Therefore, although these statements are analytic, so to speak, yet they exhibit real progress in our knowledge of the real.
Last piece of evidence in this brief: Consider the progression from Q. 2 of the Prima pars through Q. 11 of the same. Deductions that are informative, resting on inductions that are non-hypothetically penetrating.