Reality is the name for all of physical existence as an object, wherein the universe and all of things therein are real and all things which do not exist are considered outside of reality and non-existent. The term is used to refer to the state of things as they actually exist, as opposed to an idealistic or notional idea of them, although what is "real" may include cognitive forms ( thoughts ) as they are encoded within the human mind as a physical system . Reality includes everything that is and has been, whether or not it is observable or comprehensible. A still broader definition includes that which has existed, exists, or will exist.
Philosophers, mathematicians, and other ancient and modern thinkers, such as Aristotle, Plato, Frege, Wittgenstein, and Russell, have made a distinction between thought corresponding to reality, coherent abstractions ( thoughts of things that are imaginable but not real), and that which cannot even be rationally thought . By contrast, existence is often restricted solely to that which has physical existence or has a direct basis in it in the way that thoughts do in thebrain .
Reality is often contrasted with what is imaginary, illusory, delusional, (only) in the mind , dreams, what is false, what is fictional, or what is abstract. At the same time , what is abstract plays a role both in everyday life and in academic research . For instance, causality, virtue, life , and distributive justice are abstract concepts that can be difficult to define, but they are only rarely equated with pure delusions. Both the existence and reality of abstractions are in dispute: one extreme position regards them as mere words ; another position regards them as higher truths than less abstract concepts.