Aristotle - Philosophy and Ethics
Aristotle divides science in three main categories: practical, poetical or theoretical science.
Practical science contains ethics and politics, poetical science includes the study of poetry and the other fine arts. Theoretical science means physics, metaphysics and mathematics, for example.
Because of his main occupation, Philosophy, Aristotle always wrote about these topics in a more theoretical way than a scientist by today's meaning would do.
Aristotle is credited with the earliest study of formal logic, and his conception of it was the dominant form of Western logic until the 19th century. Aristotle's teacher Plato developed a reasonable conception of a deducting system but could never acutally construct one.
In his studies on physics Aristotle assumed that there are five elements: Fire, Earth, Air, Water and a new one which he added, Aether. His physical works also contained motion, causality, optics, chance and spontaneity.
The term metaphyisics was created after Aristotle's death and means behind the physics. Aristotle defines metaphysics as the knowledge of immaterial being or of being in the highest degree of abstraction. He calls metaphysics the first philosophy and the theologic science.
Aristotle's research in the field of biology were mainly about the natural environment of the island Lesbos, where he observed the surrounding seas and also neighbouring areas. He created a classification of animals in today's called vertebrates and invertebrates and live-bearing and egg-bearing.