There is a debate in philosophy and science about whether or not the universe can fully be known. The debate centers on the conflicting ideas of reductionism and emergentism. Reductionism is the belief that all phenomena reduce to physics (or possibly mathematics) and so at some point we might know the universe entirely because we would have all the variables and all the formulas necessary to describe all phenomena. For example, we could predict stock market fluctuations because we could reduce them to human psychology, which we could reduce to physical biology, which itself would reduce to neurochemistry, which again reduces to physics, which we can describe quantifiably. Emergentism, on the other hand, holds that there are gaps in the chain of reductions that cannot be filled. In other words, some new properties simply emerge without any seeming correspondence to the system upon which it is built.