How I know what I know?

How do I know what I know? I’m not sure if the question is asking for the process of learning or if we actually know what we “know” to be knowledge, or some form of truth. The former is a much easier question. We know what we know from our life and experiences. As we experience different views from different people in different environments, who, themselves, grew up with their own experiences, we develop our own thoughts.

But how do we know that these thoughts are true? We don’t I guess. We’re never sure about our beliefs. There is nothing that tells us that we haven’t been lied to our whole life. It’s like the idea that we might just be brains floating in a vat, with electrical impulses being sent to us to imagine everything. Arguments that this cannot be true mostly revolve around how having all those impulses to our brains for all we feel in our life would be too complex. But what if the world our brains floated in worked by different rules? If this existence is a figment of our imagination, how do we know that these are the rules that the “real life” follows? Our dreams don’t always follow the rules of physics. There is no reason to believe that we aren’t simply brains floating around.

So that’s the scary thing. We don’t know that we know anything in the end. We may have learned it from our experiences, but we can’t tell if these were lies.