  Reid translates Newton's first rule from Latin as “No more causes, nor any other causes of natural effects ought to be admitted, but such as are both true, and are sufficient for explaining their appearances” and adds in his own voice, “This is a golden rule; it is the true and proper test, by which what is sound and solid in philosophy may be distinguished from what is hollow and vain” (EIP 1.3, 51). Reid expands the intended scope of this rule saying that it is a “fundamental principle in our enquiries into the structure of the mind, and its operations” (EIP 1.3, 51). Occurring in the introductory portion of his Essays on Intellectual Powers, he would go on to use and reuse it countless times in what followed. He also describes Newton's first rule as “a dictate of common sense” (EIP 2.6, 102). Proponents of the Way of Ideas fail to abide by Newton's first rule when they endorse the existence of ideas because the existence of ideas is an hypothesis and lacks evidence.