APRIORISM—a gnoseological tendency according to which valid a priori knowledge exists (moderate apriorism), or all valid knowledge is obtained only a priori (radical apriorism); apriorism is opposed to asposteriorism or empiricism which gives experience the dominant role in cognition (a priori—a posteriori).
Apriorism is sometimes identified with rationalism. More often, however, rationalism is understood as opposed to irrationalism rather than to empiricism. Apriorism may be psychological (genetic apriorism), epistemological, and methodological. According to psychological apriorism, there are innate concepts and judgments in the human mind, or at least the mind is so constituted that it must construct certain concepts rather than others, and it must arrive at certain judgments rather than others, regardless of what the senses provide to the mind (nativism). Epistemological apriorism recognizes only a priori knowledge as possessing full cognitive value.
Methodological apriorism does not recognize any thesis not justified on the basis of a priori truths (radical methodological apriorism), or it holds that at least some theses about the world can be legitimized without any appeal to experience (moderate methodological apriorism).
Among ancient thinkers apriorism appeared in an agressive and radical form. Parmenides denied that experience has any value in our knowledge of reality. Plato connected genetic apriorism to that thesis. Apriorism later lost its strength. It only defended the right to accept assertions not based directly or indirectly on empirical knowledge or data: in Augustine’s illuminationism, in Anselm of Canterbury’s ontological proof for the existence of God, and in Bonaventure’s theory of “eternal principles”. In the seventeenth century, apriorism was reborn among those who recognized a mathematical component in natural science (Galileo, I. Newton), in R. Descartes’ doctrine of innate ideas, in G. W. Leibniz’ characteristics of primary truths, and in N. Malebranche’s ontologism. I. Kant initiated modern ontologism. Kant thought that by the pure imagination we may grasp general truths in the objects evident to our minds, that is, we may create synthetic a priori assertions. The assumptions of applied mathematics and the so-called principles of the reason are of this sort. The development of the a priori deductive sciences (non-Euclidean geometries, formalization) and evolutionism undermined Kant’s position, but his position found a voice in another form in the thought of E. Husserl. Husserl said that on the basis of an inspection or insight into a thing’s essence we can arrive absolutely certain general assertions that could not be obtained on the basis of sense experience. The axioms of applied mathematics are not thereby analytic but express knowledge about ideal constructs (axiom). A certain apriorism is evident in H. Spencer’s theory of “innate forms of thought”, in A. Riehl’s epistemology, a biologically and sociologically oriented apriorism in history in G. Simmel, in modern ontologism, and in B. Bolzano’s theory of evidence. Sometimes apriorism occurs in the conceptions of theoretical physics. However, apriorism appears more and more in a moderate form. The structures of knowledge and the formal rules for grasping and utilizing what is given in experience are truly a priori, but they are subject to certain verifications and modifications under the influence of experience. It is fashionable to say that there is a dialogue between reason and the senses (G. Bachelard), that the reason is open to experience, and that the a priori is relative and functional (A. Pap), or hypothetical (J. Ullmo). On the other hand, some writers emphasize that the reason is not passive in experience, and that the reason has initiative and a directing role in cognition. If one accepts assertions that go beyond empirical knowledge, one accepts them as analytic a posteriori (as stating the only reasons that render the data of experience free of contradiction). In the logical theory of science these matters are discussed in the analysis of the relation of theoretical concepts to experience, and in the analysis the relation of analytic propositions to synthetic propositions, and it is widely agreed that there is not a sharp boundary between theoretical and observational terms, and above mentioned types of propositions.
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