We have a set of tools now for operating on truths, but we lack the raw materials to operate on. Fortunately there is another common epistemic view.
Empiricism is the view that knowledge of reality comes from the senses. As I mentioned in my brief discussion of axiom #6, we are not assuming quite this much, though we are taking at least a partially empirical view. Our senses provide some sort of access to reality, although that access may be mediated, transformed, inconsistent, etc. Due to this caveat, we cannot simply make knowledge-claims based on our senses: “I see _ therefore I know that _.” could be perfectly wrong.
However, we can say “I see _ therefore I know that something in reality is causing me to see _”. This is somewhat more accurate though less useful. More importantly, we can appeal to the consistency of reality (axiom #3), the partial consistency of memory (axiom #7), and the validity of logic (axiom #8) to make probabilistic empirical claims, such as the following:
I see _, and I have many memories of seeing the same _, therefore it is probable that I will continue to see _.
Of course sight is not the only possible sense here; one can make similar claims using hearing, smell, touch, etc. By adding an appeal to causality (axiom #5) one can also make probabilistic claims about correlation:
I see X and have a memory of just seeing Y. I have many memories of seeing X shortly after seeing Y, and no memories of not seeing X after seeing Y. Therefore it is probable that if I again see Y, I will shortly see X.
(I use X and Y instead of _ above because I have two blanks to fill in that I wish to distinguish between). Just like any probabilistic claim, the more samples you have (in this case memories) the stronger the claim.
It is these probabilistic claims that we can use as raw materials, feeding them into our rational tools to produce an understanding of reality. Of course we cannot use this to achieve whatever constitutes “real” truth with any certainty, but strong probabilities are better than nothing. With rationalism and empiricism in hand we will use the next post to delve more deeply into the concepts of truth and knowledge.