SubstanceAs humans we have the ability to think and reason, and that is why we have evolved the way we have evolved. However, we can never be sure that what we think and what we reason is really the truth. And that idea can lead a person to ask certain questions; What is the nature of existence? What is the nature of reality and its principles? but then other questions follow within These; What are we touching? What are we looking at? What are these things that interfere and alter our lives? Are they the same in reality as they are in our minds? What are these substances? Are they even substances? If they are real, then why are they real and what are they? Many great philosophers have addressed these questions. Philosophers such as Plato, Aristotle, Descartes, Spinoza and Berkeley. All of them had an idea of ​​what the substance is. Plato's whole idea of ​​forms is what would be considered substance. Form is the standard model or ideal model of the object or action that is named or mentioned. To understand the natural world and/or the material world, we must associate them with the substance we find in the intelligible world. Sensory perception only concerns the superficial appearance of things and is therefore useless for understanding the world. These forms are necessary not only to understand the material world, but also to understand language itself. These forms of substance are a good way to explain what we understand about the natural, material world. Aristotle refuted Plato's idea of ​​forms. He felt that shapes caused neither movement nor change, nor did they help one understand what is real and what is knowable. Aristotle presents the concept of substance in his work “The Categories”. He states that substance is the fusion of matter and form. Matter is that from which substance arises and form is that into which matter develops. In building a table, wood, nails, etc., are important. The idea of ​​a table is the form, the construction is the fusion and the final result is the substance. René Descartes began by doubting everything. For Descartes, reason was both the foundation and the guide for pursuing the truth. He wanted to bring some certainty into his life. So he started over again. He rejected everything he had been taught. He rejected God, the Church, Aristotle, everything else... middle of paper... as if our mind is thinking predictions of what the spirit is creating. Everyone has clear ideas about what substance IS. The first two relate substance to ideas intelligible through the mind. The last three relate substance through God and perception. The philosopher I can almost agree with is Aristotle. I agree that substance is the creation of our thoughts and works. I can't relate to the idea of ​​God creating everything and being the reason for everything. I believe things are what they are for no reason. I don't see why there needs to be one. I am who I am and that's all, however I like the fact that my mind can expand to newer and brighter ideas, so maybe I might think differently over time and experience. Works Cited 1. The Internet Encyclopedia of Philosophy 1997 Rene Descartes (http://www.utm.edu/research/iep/d/descarte.htm)2.The Ethics (1677) by Benedict de Spinoza Scanned and corrected by Edward A. Beach, Department of Philosophy and Religion, University of. Evansville (http://www.knuten.liu.se/~bjoch509/) 3.Levenson, Carl; Jonathan Westphal. Reality. Indianapolis, Indiana Hackett Publishing Company, Inc. 1994