Nozick, methods and knowledge

Philosopher Robert Nozick challenges the Gettier cases in his essay "Knowledge and Skepticism." He proposes a new definition of knowledge which, unlike Klein's, does not rely explicity on the introduction of new evidence to a specific person or whether some new proposition might come that defeats that person's previous belief. Instead, Nozick makes knowledge dependent on truth and a method for arriving at truth.

Nozick gives the following definition of knowledge:

S knows that p via M iff

1. p is true
2. S believes, via method M, that p
3. If p weren't true and S were to use M to arrive at a belief whether p, then S wouldn't believe, via M, that p.
4. If p were true and S were to use M to arrive at a belief whether p, then S would believe, via M, that p.

I'll explain this definition. The definition means that you know something when it's true, you believe it's true because you've arrived at it through some method or other, and then two more things. If something weren't true and you used that method mentioned earlier to arrive at it, then you wouldn't believe that thing were true. Conversely, if something were true and used that method mentioned earlier to arrive at it, then you would believe that thing were true.

This raises the question of how a person discovers the truth, or what methods one must use. Can the methods conflict, for example? But now these are empirical matters.