Metaphysics (from the Greek words μετά (metá) (meaning "beyond" or "after") and φυσικά (physiká) (meaning "physical" or “ physics”) about the works on matter by Aristotle, is a branch of philosophy investigating principles of reality and explaining the fundamental nature of being.
According to Aristotle, the first known metaphysician was Thales from Miletus, Ionia, who conceived Arche''', the source, first principle, that of moisture translated as "water." Other Miletians, such as Anaximander and Anaximenes, also from Miletus, had a monistic conception of Arche. According to Thales the universe was a harmoniously structured being subject to rational understanding.
Parmenides of Elea, South Italy, however, held that the multiplicity of existing things, their changing forms and motion, are but an appearance of a single eternal reality (“Being”), thus giving rise to the Parmenidean principle that “all is one. From this concept of Being, he went on to say that all claims of change or of non-Being are illogical. Because he introduced the method of basing claims about appearances on a logical concept of Being, he is considered one of the founders of metaphysics.
Aristotle’s “first philosophy” was called “metaphysics” by the editor of his works, Andronicus of Rhodes, a scholarch of the Peripatetic School, as he placed the books on first philosophy right after Physics, another work by Aristotle (τὰ μετὰ τὰ φυσικὰ βιβλία, ta meta ta physika biblia).
Metaphysics was divided into three parts that are now regarded as the traditional Western metaphysics:
The study of a God or Gods; involves many topics, including among others the nature of religion and the world, existence of the divine, questions about Creation, and the numerous religious or spiritual issues that concern humankind in general.
The study of first principles, which Aristotle believed to be the foundation of all other inquiries. An example of such a principle is the law of noncontradiction and the status it holds in non-paraconsistenlogics.
Metaphysics as a discipline was a central part of academic inquiry and scholarly education even before the age of Aristotle. During the seventeenth century, problems that were not originally considered within the bounds of metaphysics have been added to it, while other problems considered metaphysical for centuries are now investigated in separate regions in philosophy, such as philosophy of religion, philosophy of mind, philosophy of perception, philosophy of language, and philosophy of science.