In philosophy and science, we quite often make systematic approaches that limits our thoughts to be as accurate as possible.
Examples are endless - basically every logical system, every epistemological research, they all at some level try to do things similar to (merely the best example I can think of) Popper with the distinction of science and pseudo-science. We make assumptions for what is true, such as it has to be logical, it has to make sense, it has to have clear connection to our empirical world, it has to be compatible with our moral beliefs, etc.
I ask, why do we make such assumptions about the nature of the world? How do we know it even fits within our possible scope of knowledge? What keeps us from having a completely skeptical (Hume style, though even he wasn't completely skeptical) view on the world, or the radical theistic view of "we can't know nothing about nature because God works in mysterious ways"?
This question seem to aim for skepticism at its core, but do note that the question is mainly about the "limiting" of the possibilities of truth.