Aristotle was the first philosopher to approach the study of nature in a systematic way, establishing science as a discipline and providing a starting place for natural philosophers into the Middle Ages.

Born in Stagira in northern Greece and the son of the physician to Amyntas II of Macedonia (r. c. 393-370/369), Aristotle came to Athens when he was seventeen years old and studied at Plato’s Academy for twenty years. When Plato died in 347 b.c.e., Aristotle left the academy and traveled for twelve years, visiting various centers of learning in Asia Minor and Macedonia. During this period of travel, he developed his interest in the natural sciences, to which he applied his method of inquiry. He returned to Athens in 335 b.c.e. after a brief period of tutoring Alexander the Great (356-323 b.c.e.), Amyntas’s grandson, and established the Lyceum, a school that became a center of learning. He taught there until a year before his death. Aristotle

The range of topics discussed and developed by Aristotle at the Lyceum is overwhelming: natural philosophy with its considerations of space, time, and motion; the heavenly bodies; life and psychic activities; ethical and political problems; animals and biological matters; and rhetoric and poetics. Further, he is sometimes credited with creating new fields of research, such as terrestrial dynamics and optics. He also taxonomized plants and animals and organized earlier Greeks’ ideas about planetary astronomy in Peri ouranou (c. 350 b.c.e.; On the Heavens, 1939).

Aristotle.

(Library of Congress)

Perhaps the most significant aspect of Aristotle’s work is his development of a “scientific” approach to these studies. This “scientific” approach recognizes the existence of independent disciplines, each employing its own principles and hypotheses. Such an approach also works out a methodology or procedure for each field of study, aiming at true and certain knowledge.

The Greek term that Aristotle uses for “scientific knowledge” is episteme, which can best be translated as “true knowledge” or the “most certain knowledge.” This knowledge includes the awareness of an object, of its causes, and that it can be no other way. Medieval scholars translated the Greek episteme as the Latin scientia, which came into English as “science.”

In recognizing independent fields of study, Aristotle showed a significant departure from Plato’s philosophy. Plato had envisioned one single science. For him, true knowledge was the contemplation of the Forms: Virtue, Justice, Beauty, and Goodness. All other disciplines were subordinate to knowledge of the Forms. Aristotle, on the other hand, did not advocate a hierarchical structure of knowledge. Each study locates its own particular subject matter and defines its principles from which conclusions are to be drawn. Almost all his treatises begin with the same format: “Our task here concerns demonstrative science,” that is, logic; or “Human conduct belongs to political science.”

Aristotle’s insistence on the division of sciences, each using special principles, is indicative of his rejection of any absolute master plan of knowledge. He does, however, recognize “common principles,” or principles shared by more than one science. For example, the “equals from equals” principle of mathematics can be used in geometry to deduce a conclusion about a line. Aristotle warns the geometrician, however, that this can be done “if he assumes the truth not universally, but only of magnitudes.” Aristotle never intends the same common principles to be universally applied in exactly the same way throughout all the sciences. If this were the case, there would not be “sciences,” but rather “Science.”

The second important feature of Aristotle’s scientific approach concerns methodology. In the Analytica posterioria (335-323 b.c.e.; Posterior Analytics, 1812), he develops the general technique that the particular disciplines are to employ in order to achieve scientific knowledge. First, an investigation must always begin with what is “better known” to humans. They must begin with observable data and facts, and not construct wild hypotheses. Second, human beings must proceed to a knowledge of the cause of the facts; mere observation is not enough. Observing something only indicates that something is the case; it does not explain why it is the case. Learning the cause tells people why, and this involves a logical demonstration. Third, the cause or reason of the fact must be of “that fact and no other.” This criterion is the basis for a scientific law because it demands a universal connection between the subject and its attributes.

The second and third criteria require a deductive system of demonstration that is expressed in the universal positive form of the syllogism that Aristotle developed in the Analytica priora (335-323 b.c.e.; Prior Analytics, 1812). There is also what might be called an “inductive” approach to his method of science. Aristotle raises the question of how humans know the universal principles from which demonstration is to proceed. He answers that human knowledge of such principles begins with many sense perceptions of similar events. Human memory unifies these perceptions into a single experience. The human intellect or mind then understands the universal import of the experience. From many similar experiences, humans recognize a universal pattern.

Aristotle’s method of science combines the theoretical and the practical. The theoretical aspect includes logical demonstrations and universal principles. The practical includes the necessary role of sense perception as it relates to particular objects. In the Metaphysica (335-323 b.c.e.; Metaphysics, 1801), he warns that physicians do not cure men-in-general in a universal sense; rather they cure Socrates or Callias, a particular man. He adds that one who knows medical theory dealing with universals without experience with particulars will fail to effect a cure. Instead, he advises the use of procedures grounded in common sense that have proven their validity in practice.

One application of this method is in Aristotle’s writings on biology. He makes theoretical interpretations based on his dissection of marine animals and empirical observations, although he does also rely on other writers’ descriptions of some animals. Based on these researches, he arranges a “ladder of nature.” Because he can see changes in the realm of plants and animals, he affirms the reality of nature and the value of its study. He is optimistic that he could use natural history to find causal explanations of physiology.

For Aristotle, scientific knowledge included the observation of concrete data, the formulation of universal principles, and the construction of logical proofs. Greek “science” prior to Aristotle, largely a melange of philosophical and quasimythological assumptions, blossomed after his investigations into the specialized work of Theophrastus (c. 372-c. 287 b.c.e.) in botany, Herophilus (c. 335-c. 280 b.c.e.) in medicine, and Aristarchus of Samos (c. 310-c. 230 b.c.e.) in astronomy.

Aristotle also pioneered the notion that there are many, distinct disciplines of knowledge rather than a single, unified science; that there are multiple structuring principles for these disciplines rather than one, overarching set of concepts applicable to them all; that standards of scientific rigor vary among disciplines; and that there is no single, universal scientific method. At the same time, he believed in systematic, empirical investigation of natural phenomena, from which general theories might arise, as opposed to creating a theoretical structure and then fitting the data into it. His identification of many of the scientific disciplines and his methodology for studying them remain valid today.

• Barnes, Jonathan, ed. The Cambridge Companion to Aristotle. New York: Cambridge University Press, 1995. A straightforward, readable introduction to Aristotle’s thought for nonspecialists and students. Essays offer a clear exposition of his central philosophical concerns.
• Bolton, Robert, and Robin Smith, eds. Logic, Dialectic, and Science in Aristotle. Special issue of Ancient Philosophy 14 (1994). Seven scholars of ancient Greek philosophy try to resolve puzzling sections in Aristotle’s works on these subjects.
• Byrne, Patrick H. Analysis and Science in Aristotle. Albany: State University of New York Press, 1997. Offers a new interpretation of Aristotle’s Prior and Posterior Analytics as a unified whole, arguing that a nondeductive form of ancient mathematical analysis influenced Aristotle’s thinking. Reading the Analytics with this perspective in mind sheds new light on Aristotle’s theories of the syllogism, demonstration, and the principles of science.
• Ferejohn, Michael. The Origins of Aristotelian Science. New Haven, Conn.: Yale University Press, 1991. An in-depth discussion of the theoretical structure of Aristotle’s scientific method.
• Golthelf, Allan, and James G. Lennox, eds. Philosophical Issues in Aristotle’s Biology. Cambridge: Cambridge University Press, 1987. Noted Aristotelian scholars focus on the relationship between Aristotle’s biological researches and writings and the methods he proposed in works such as the Analytics.
• Lindberg, David C. The Beginnings of Western Science. Chicago: University of Chicago Press, 1992. An introductory-level, award-winning book which aims clear and thorough explanations of ancient and medieval scientific ideas to a diverse audience.
• McKeon, Richard. Introduction to Aristotle. Reprint. New York: Modern Library, 1992. A general introduction to Aristotle which mainly includes selections from a number of his works, with some discussion of his scientific method.
• Sfendoni-Mentzou, Demetra, et al., eds. Aristotle and Contemporary Science. 2 vols. New York: P. Lang, 2000-2001. A collection of essays from a symposium held in 1997 assessing Aristotle’s continuing influence on science in fields such as Newtonian and quantum mechanics, relativity theory, mathematics, cosmology, biology, psychology, philosophy of mind, logic, ethics, politics, poetics, and economics.

Anaximander; Anaximenes of Miletus; Apollonius of Perga; Archimedes; Aristotle; Empedocles; Eudoxus of Cnidus; Hero of Alexandria; Hypatia; Plato; Pliny the Elder; Thales of Miletus. Science, beginning of scholarly discipline of