Parsimony, in science, refers to the principle that a hypothesis
should explain as much as possible with the least possible complexity. The simplest, or most parsimonious, explanations rank higher, provided they explain equally.
In order to improve, or refine a scientific theory, the new improvement must be parsimonious. In other words, it must not only explain the weakness it attempts to explain, but additonal weaknesses as well. This requirement comes from the work of Karl Popper and is intended to prevent patchwork theories, or to see them replaced with sounder ideas.