Aristotle was responsible for major developments in many fields that are still studied today, including logic, zoology, science, astronomy and many more. Although many of his theories were eventually supplanted by more developed studies, his ideas were incredibly influential, and many of them still form the basis of modern thought.
Aristotle's "Prior Analytics" is considered the earliest study of formal logic. Aristotle's ideas about logic were the basis of the field for over 2000 years until advances in mathematical logic displaced them in the early 19th century. The philosopher Immanuel Kant asserted in his landmark "Critique of Pure Reason" that Aristotle's ideas of logic formed the core of the notion of deductive reasoning.
Aristotle also performed pioneering research in zoology, classifying animals into different types based on physical characteristics. He perceived a continuum of simpler and more complex forms of life, and in devising the beginnings of taxonomic classification, he is celebrated as the father of zoology. Though he used different terms, he recognized a fundamental distinction between vertebrates and invertebrates. He was able to distinguish whales and dolphins from fish and completed anatomical studies of cephalopods and crustaceans that are still valid today. Aristotle articulated an understanding of the water cycle long before it could be verified and also determined that the Earth is round.