ABSTRACT
In ancient medicine, similarity principle claimed that when a substance is able to induce a series of symptoms in a healthy living system, it would be also able under certain circumstances to cure these symptoms when applied at low doses. However, the similarity principle is a different, general principle in scientific discovery. The similarity principle says that every characteristic/element of an object contributes a portion of information to real-world outcomes; therefore, the more similarity between two objects the more likely they produce the same output when they receive the same input. According to Albert Einstein, the grand aim of all science is to explain the greatest number of empirical facts by logical deduction from the smallest number of hypotheses or axioms. The root of causality is the similarity principle, and the similarity principle is at the root of all science. There are different measures of similarities, each having its own characteristics and applicability to particular problems.
