The principle of parsimony, often referred to as Occam's Razor, states that when presented with competing hypotheses about the same prediction, one should select the solution with the least number of assumptions. In scientific reasoning, this principle serves as a heuristic to guide researchers towards simpler explanations. By favoring simpler models over more complex ones, scientists can reduce the risk of introducing unnecessary variables, making findings clearer and more reliable. It emphasizes the importance of simplicity in constructing theories and understanding natural phenomena.