Aristotle's Philosophy of Scientific Knowledge
Throughout his life, Aristotle was driven by one overwhelming desire for knowledge. His whole career testifies to the fact that he was concerned before all else to promote the discovery of truth and to increase the sum of human knowledge. Aristotle’s theory of scientific knowledge is the first elaborated theory in the Western philosophical and scientific traditions of the nature and structure of science. Since the philosophical content of his theory is extremely important, the main aim of this essay is to outline Aristotle’s approach to the problem of knowledge in order to further help understanding his contribution to the structure and development of the theory of scientific knowledge.
Aristotle was the systematic philosopher of ancient times and the corpus of his own works covers almost every major area of human inquiry. It includes writings on natural science and analyses of its important concepts, from physics and astronomy to biology and psychology. Acquisition of knowledge was dealt with in different parts of Aristotle’s extensive works, such as the two Analytics. In the Prior Analytics, Aristotle developed his theory of syllogism as a tool for science, and in the Posterior Analytics, he discussed the problem of knowledge: what it is, how it is acquired, how guaranteed to be true, how extended and organised.
Aristotle divided knowledge into three major classes. He believed that “all thought is either practical or productive or theoretical”. The productive sciences are those concerned with the making of things such as art, engineering, cosmetics and farming. Aristotle himself had relatively little to reveal about productive knowledge. The practical sciences are concerned with action, i.e., with how one have to act in different circumstances, whether in private or in public affairs. Knowledge is theoretical when its goal is neither productive nor action but simply truth. Theoretical knowledge includes all that one now thinks of as science, and in Aristotle’s view it contained by far the greatest part of the sum of human knowledge. The following diagram shows how Aristotle regarded the structure of human scientific knowledge.
The fundamental concepts of Aristotle’s theory of scientific knowledge begin with the general assertion that “all intellectual teaching and learning arise from preexisting knowledge”. Aristotle argued that two kinds of preliminary knowledge are required; knowledge that something is, and knowledge of what the thing mentioned is. This previous knowledge may relate to the existence of some thing or fact, or to the definition or meaning of some terms. It must also be clearly settled that: “Scientific knowledge cannot be acquired by sense-perception”; and that: scientific knowledge is gathered by applying the syllogistic method, that is, as Aristotle shows, how one scientifically explains certain facts and phenomena concerning certain kinds by showing how they logically follow from certain first principles.
Aristotle also acknowledged that one way of having scientific knowledge is knowing by means of demonstration. He defines demonstration as a “scientific deduction”. Aristotle believed that there is a kind of deduction that yields scientific knowledge and by possessing it, one satisfies the conditions of scientific knowledge. A demonstration is a deduction that involves the essential truth of its conclusion. But because not every valid deduction is a scientific demonstration, the difference between proofs and other valid deduction will exist in the nature of the premises. However, to identify requirements such that any valid deduction from premises meeting the requirements will be a demonstration, Aristotle identified six requirements. He stated: “Demonstrative scientific knowledge must depend on things that are true, primary, immediate, better known than, prior to, and grounds of the conclusion”. Aristotle explained that these six requirements are not necessarily be requirements for premises, but that demonstrative scientific knowledge depends on, or proceeds from, things that are true and so on. Even if the principle of one proof is the deduction of another, every conclusion depends, in the end, on unproved principle. Therefore, a premise meeting the above mentioned six requirements is a principle. However, one can realise that Aristotle’s main concern was the articulation of the logical structure of scientific explanations, not the establishment of a program or methodology for scientific research and inquiry.
Aristotle also listed the characteristics of the premises: “The premises, then, must be true statements; because it is impossible to know that which is contrary to fact, e.g., that the diagonal of a square is commensurate with the sides. They must be primary and indemonstrable, because otherwise we shall not know them unless we have proofs of them”. It follows that primary premises and principles must be identical notions: “To depend on things that are primary is to depend on appropriate principles [archi oikeiai], for I call what is primary and a principle the same thing. A principle of a demonstration is an immediate proposition, and an immediate proposition is one to which no other proposition is prior”. However, since scientific knowledge depends on primary, immediate proposition, it depends on principles. And since a prior knowledge of principles is required for scientific knowledge of the conclusions, all scientific knowledge depends on knowledge of the principles.
This leads Aristotle to speak of the axioms: “I apply the term ‘thesis’ to an immediate indemonstrable first principle of syllogism the grasp of which is not necessary for the acquisition of certain kinds of knowledge; but that [first principle] which must be grasped if any knowledge is to be acquired, I call an ‘axiom’ (axioma)”. Aristotle thus defines axioms as an indemonstrable first principle absolutely essential for the acquisition of scientific knowledge. Thus if the first principles are indemonstrable, and if everything that can claim to be a scientific knowledge is nothing but a conclusion from these first principles, then no scientific knowledge can be acquired unless these first principles are somehow revealed through other means. Taken together, these deliberations show that if the initial premises are true, and the concepts achieved by demonstrative knowledge are also necessarily true, then, inevitably, the status of the axioms in Aristotle’s theory of knowledge becomes essential.
Plato suggested that the whole of human knowledge might somehow be a set out in a single axiomatized system i.e., from a small set of primary truths, every other scientific truth might be logically deduced. Unlike Plato, Aristotle did not believe that all knowledge could be founded upon a single set of axioms, for he was equally impressed by the obvious independence of the sciences. Aristotle stated: “The causes and principles of different things are different – in one way; but in another way, if you speak universally and by analogy, they are all the same”. This means that the axioms of geometry and the principles of biology, for example, are mutually independent, but they are the same by analogy. That is to say that the conceptual methods and the formal structure of all sciences are the same.
In his Aristotle: A Very Short Introduction, Jonathan Barnes argues that the construction of an axiomatized deductive science, which is the production of proofs, depends upon the presence of all the true facts of the case. He believed that Aristotle never had a grasp of all the facts and that he sometimes jumped directly into theorising. Barnes explains that theory should to some extent control the collection of facts and that undisciplined amassing of facts is an unscientific exercise. Some philosophers, both ancient and modern, have also argued that there is no such thing as a pure fact uncontaminated by theory. Even if some critics do not share Aristotle’s vision, the effort to understand his theory as a whole may lead to healthy critical reflection on contemporary outlook. In fact, as the preceding discussion shows, Aristotle established a consistent model for scientific paradigms as well as specified what was needed to set any intellectual discipline on the road to progress. Undoubtedly, Aristotle’s conception of scientific principles makes for a theory that is consistent and economical and makes the conception of demonstrative science of even greater interest today.
What is of great philosophical significance in the present context is the fact that the whole Aristotelian logic as an abstract enterprise concerning the structure of propositions and syllogistic arguments would not have been possible without commitment to a sufficiently advanced knowledge based on an elaborated and structured theory of scientific knowledge. This is the insight, however, vaguely visible in Plato, Aristotle and all the succeeding generations of philosophers, that knowledge is identifiable invariably as an objective, though abstract, structure of propositions that are true and language-independent. Although, the range and complexity of scientific knowledge have increased beyond anything that could then have been conjectured, Aristotle’s investigations in the Posterior Analytics is a significant contribution to the analysis of the problem of scientific knowledge and still provide valuable insights to a contemporary reader. Undoubtedly, Aristotle occupies a unique position in the whole history of philosophy.
Barnes, Jonathan, Aristotle: A Very Short Introduction. New York, 2000.
Brisson, Luc and F. Walter Meyerstein, Inventing the Universe: Plato’s Timaeus, the
Big Bang, and the Problem of Scientific Knowledge. New York, 1995.
Edel, Abraham, Aristotle and His Philosophy. New Jersey, 1982.
Goldin, Owen, Explaining an Eclipse: Aristotle’s Posterior Analytics 2.1-10. Michigan, 1996.
McKirahan, Richard D., Principles and Proofs: Aristotle’s Theory of Demonstrative. New Jersey, 1992.