Human Engineering will not interfere with any scientific research; on the contrary, it will promote it in many ways. Grown-ups, it is to be hoped, will stop the nonsense of intermixing dimensions, for which we chastise children. It is the same kind of blundering as when we intermix phenomena—measuring “God” by human standards, or human beings by animal standards. The relationship, if any, between these phenomena or the overlapping of different classes, is interesting and important; but in studying such relationships of classes, it is fatal to mix the classes; for example, if we are studying the relations between surfaces and solids, it is fatal to mistake solids for surfaces; just so, too, if we stupidly confuse humans with animals. In the reality of life, we are interested only in the values of the function of the phenomena by themselves and to arrive at right conclusions we have to use units appropriate to the phenomena. The intermixing of units gives us a wrong conception of the values of each phenomenon; the results of our calculations are wrong and the outcome is a misconception of the process of human life. The fact once realized, we will cease applying animal measures to man; even theology will abandon the monstrous habit. Animal units and standards are to be applied to animals, human standards to man, “Divine” standards to “God.” In the dark ages, with the complete innocence or misunderstanding of science, the “why” of things was explained by the “who” of things; therein investigation culminated; man was regarded as _homo sapiens_ and homo sapiens = animal × spark of _super_natural; this monstrous formula was accepted as a final truth—as an answer to the question: What is Man? This type of answer became in the hands of church and state a powerful instrument for keeping the people in subjection. The tendency of the masses to let others think for them is not really a _natural_ characteristic—quite the opposite. The habit of not thinking for one’s self is the result of thousands of years of subjection. Those in authority, in general, used their ingenuity to keep the people from thinking. The most vital reason why many humans appear to be, and are often called, “stupid,” is that they have been spoken to in a language of speculation which they instinctively dislike and distrust; thus there arose the proverb that speech was made to conceal the truth. It is no wonder that they appear “stupid,” the wonder is that they are not more “stupid.” The truth is that they will be found to be far less stupid when addressed in the natural language of ascertainable fact. My whole theory is based upon, and is in harmony with, the natural feelings of man. The conceptions I introduce are based on human _nature_. Natural language—so different from the speech of metaphysical speculation—will lead to mutual understanding and the disappearance of warring factions.