Descartes believed that the mind was separate from the physical world and inherently different from it. This is called dualism. Monists believe that mind and body are essentially the same thing. Experiments in quantum theory which appear to show that the act of observation can determine whether or not a subatomic particle takes the form of a particle or wave, has led some such as Roger Penrose to believe that consciousness is inherent in matter and permeates the entire universe. https://en.wikipedia.org/wiki/Roger_Penrose

In philosophical terms, skeptics believe that it is impossible to know with absolute certainty what is going on in someone else's mind. Jung believed that our minds were all connected through the collective unconscious.

mind) which contains Box A. This is a logical argument because it follows from a series of logical premises.

Skepticism in philosophy is the idea that nothing, or can be understood with absolute certainty.

A skeptic might argue argue that it is impossible for the mind to understand itself. Box A (the mind) cannot contain Box B (a theory of

Epistemology is concerned with how we know if any of this is true.

https://en.wikipedia.org/wiki/Outline_of_epistemol...

and this should make everything clear. https://www.youtube.com/watch?v=-2gJamguN04 ....or maybe not

Big questions. Take a course. My opinion would hardly help much. "Reality is a communication between god and man." -Berkeley