EpistemologyEpistemology is the theory of knowledge. The philosophy of understanding which determines the limitations of knowledge. The foundations of science depend on epistemology. Important questions are what is truth? How do we know? Absolutists such as Plato think that there is some perfect knowledge, an absolute truth that exists although we might never discover it. Relativists deny that there is an absolute truth and argue that knowledge depends on context.
Hume and InductionThe value of science is that it makes predictions about the future, usually these are based on past experiences. This assumes that the past is representative of the future. This process is called inductive inference. The question is have we observed all of the possibilities, so that our predictions are likely to be correct or are there any unknowns, either known or even worse might their be unknown unknowns (see Rumsfeld)? Hume said that it was not logically justified but this is how we actually operate.
Popper and FalsificationPopper argued that science cannot procede by induction and suggested that it develops by "conjecture and refutation". Scientists propose models of the world (theories and hypotheses) which are they then seek to falsify. We cannot prove a hypothesis true, but any theory that cannot be falsified cannot be a part of science. This is a way of undermining pseudo-science such as astrology which does not try to provide a falsification.
Kuhn's Scientific Revolutions
In the structure of scientific revolutions Kuhn argued that "normal science" takes place in the context of scientific paradigms (fundamental world views) which define how we create our models/hypotheses. Sometimes these paradigms fail during revolutions which follow a period of crisis when existing science faces an increasing number of paradoxes. One example is the Copernican revolution in astronomy. The fluid model of electrical conduction is another important example as is the move to quantum mechanics from classical mechanics. At the minute both physics and biology are facing a period with an increasing number of puzzles and paradoxes and so it is possible that we are entering another paradigm change.
This is the view of William James. The question we should always ask is "What practical difference does it make?" If the answer is none then the alternatives can be implied to be the same. So a belief is true if if helps us practically - is it useful, helpful applicable. This is the nature of Truth. Probably this is close to how most scientists think. Is it also applicable to religion? Can we just believe certain tenets of faiths because they make a practical difference to our experience of our lives?