How does maximum parsimony in evolutionary biology use the logic of Occam’s razor?

In evolutionary biology, the method of maximum parsimony applies the logic of Occam’s razor—a principle attributed to the philosopher William of Ockham—by prioritizing the simplest explanation for a given phenomenon.123

Specifically, maximum parsimony seeks to reconstruct an evolutionary tree that requires the fewest number of evolutionary changes across all branches. This approach operates on the assumption that the most parsimonious path is the most likely to be correct, mirroring Ockham’s directive that "plurality should not be posited without necessity".432

However, this application is a subject of debate within the scientific community. Because evolution does not always follow a minimum path—as changes can occur independently or involve complex intermediate steps—relying solely on parsimony risks oversimplifying biological history. Consequently, while it serves as a useful heuristic, it is not considered an absolute rule, and researchers often incorporate additional data, such as the varying probabilities of specific genetic mutations, to refine their models.34