Questions about example sentences with, and the definition and usage of "Foundational"

A: @studentHiro the entire phrase is hard to understand. I think it is trying to say that since nobody really knows where humans came from, there are (technically) made up stories to explain it.

A: Using teamwork as an example: A foundation is the BASIS of teamwork. You can’t have teamwork at all without it. Fundamental means that teamwork is an important PART of what they do. So you can have have a team without teamwork but it won’t be the same.

A: Foundational comes from the word foundation as in the base.
Assumption comes from assume, which is to come up with an idea without any proof or perhaps based on context.

Together, foundational assumption is referring to a base idea that supports this person’s argument. Calling it an assumption might be saying that it lack validity/credibility

By itself, the sentence is complex and a bit strange, I’m not sure what the “foundational assumption” is that the author is referring to.