I'm not the person you asked, but...

any philosophy/belief system that is descriptive (as opposed to prescriptive/normative) will be _apodictically_certain_ to the extent that it is free from internal contradictions. in simple cases we can examine the ideas and be very confident that there are no internal contradictions.

for example: given "A implies B" and "A" then we can conclude "B".

essentially any time you formalize definitions to the point that a statement of equivalence becomes obvious as a tautology, then you have an idea you can be certain about.

I have a layman's and not very well informed knowledge of philosophy, so at the risk of being savagely and justifiably owned: even in the example you give, doesn't one have to make the assumption that one's rules of reasoning are sound? I don't consider it as a serious proposition, but isn't there at least in principle the possibility that one is deluded, and that modus ponens is not universally valid, for reasons one is not capable of grasping?

I'm also an autodidact and my understanding is that radically agnostic epistemology (such as you suggest) is not very useful. the idea of a delusion presupposes that one could have a correct understanding of reality, at least in theory. the most basic assertion we can make about reality is identity, that is, a thing is itself. the purpose of a logical syllogism is to reduce an apparently complicated chain of identities to a tautology. [0]

rejection of the principle of identity leaves one at the point where no further intersubjective dialogue is meaningful. which is why Avicenna said that anyone who denies the identity should be beaten until he acknowledges that "to be beaten" is not the same as "to not be beaten" and he should be burned until he acknowledges that "being burned" is not the same as "not being burned." [1]

I'm very interested in any corrections, comments, or other replies. I'm also aware that there are other approaches to logic besides the aristotelian approach I have tried to convey above. an example of a non-aristotelian attempt at communicating would be e-prime [2].

[0] https://en.wikipedia.org/wiki/Syllogism

[1] https://en.wikipedia.org/wiki/Law_of_noncontradiction#Avicen...

[2] https://en.wikipedia.org/wiki/E-Prime

> I'm also an autodidact and my understanding is that radically agnostic epistemology (such as you suggest) is not very useful.

Oh, absolutely. I was merely suggesting that there is a difference between a lack of doubt for all practical purposes, and a lack of doubt in principle. This difference may not be terribly helpful or pertinent, of course.

Most of the ideas I hold as certain have some built-in leeway. One example that comes to mind: "A good solution now is often better than a perfect solution later."

About secrets of the Universe and primordial first principles of life.