The cow example sounds like a formulation of the Gettier problem[1]. Gettier wrote a single paper assailing the Justified True Belief theory of knowledge.

The cow example sounds like a formulation of the Gettier problem[1]. Gettier wrote a single paper assailing the Justified True Belief theory of knowledge. Suppose that you're driving past a field and you see what you believe is a sheep. It is also true that there is a sheep in the field. However, what you've actually seen is a rock. Behind the rock there stands a sheep. Do you have knowledge that there is a sheep in the field? This and related problems are a great starting point to a lot of interesting epistemology. I think you would enjoy contextualist epistemic theory. [2] [1] http://alfanos.org/pdfs/04_issues_philo_fall08/07_gettier.pdf http://alfanos.org/pdfs/04_issues_philo_fall08/07_gettier.pd... [2] http://plato.stanford.edu/entries/contextualism-epistemology/ http://plato.stanford.edu/entries/contextualism-epistemology...