[dherls]

I was thinking that one solution might be to specify that the "justification" also has to be a justified true belief. In this case, the justification that you see a cow isn't true, so it isn't a JTB.

Of course that devolves rapidly into trying to find the "base case" of knowledge that are inherent

[eynsham]

This and many other suggestions have been explored, and usually found wanting (see e.g. https://plato.stanford.edu/entries/knowledge-analysis/#NoFal...).