In the course of the struggle for existence as a result of the action of the environment, they only survive and have offspring best adapted living beings. Young people remind us that Anaximander spoke of the substance and of the law. Good for Aristotle which I try these matters thoroughly the substance meant the bodies simple, such as the Earth, fire, water and all similar things and in general of whether bodies of animals. The divine beings that has body and parts of these bodies, if the existence of the body according to some philosophers, depends of the surface, the existence of the surface of the line and climbing more the number. (Aristotle metaphysics book V Chapter VIII) definitions more modern tell us that it is the base first and invariable, everything exists, preserved despite all the transformations. Observed that there was talk of the matter, which the ancients called substance. Expose the concept of law is not easy but it can be applied to the reality of things, through logical connections that shows us the experience.
We know that the law is a necessary foundation to the Nations of the Earth, there is no it soon the same sucumbirian to anarchy and chaos. We enunciemos some laws: the law of contradiction: two statements cannot be true and false at the same time when we are talking about a subject. Example: Aristotle this sitting and is running. The law of conservation of energy: the energy going from one form to another, does not disappear, nor is created, when a material system moves from one State to another the change in its energy, strictly corresponds to the increase or to the decrease in energy of the bodies that go in and interact with the system. The biogenetic law: according to which each agency in the process of their individual development, repeats some traits and particularities of the forms were taken by their ancestors in the course of its evolution.