EMPIRICISM (from the Greek ἐκπέτρις, “experience”). — It is the valorization of facts belonging to common experience. Against the abstractions of pure speculation, this appeal to the concreteness of experience often appears in the history of philosophy.
The earliest philosophers of Greece, the pre-Socratics, already inclined toward this attitude, beginning with Thales, who resorted to water to explain the origin of things (others to air, fire, etc.). But in reality they were reacting to the fantasies and myths of the poets and legends of the preceding period; and if they began from the observation of common facts, it was only in order to construct upon them a theory that would provide the principle or principles of everything that occurs in the world—that is, a metaphysics that here had a thoroughly naturalistic character. The Sophists, by contrast, who came after them, assigned value to experience by referring exclusively to man’s daily life and to the differences between individuals. A clearer and more legitimate form of empiricism appears in Aristotle’s polemic against the Platonic theory of ideas, where he insists upon the concreteness of the reality that is the object of our knowledge, a reality that engages not only the intellect but also the senses: what truly exists is not the idea but the individual, in the richness of its sensible and conceptual determinations. Aristotle, however, already distinguished what we call “sound” empiricism from vulgar empiricism: that is, the consideration of facts accompanied by critical reflection, as opposed to mere observation. He discusses this in the first two chapters of the Metaphysics, where he observes, among other things, that “empiricists sometimes hit the mark better than those who possess theory without experience” (the emphasis concerns medical practice, in which even today the contrast between “empiricists” and “theorists” sometimes emerges). Nevertheless, Aristotle says, science is worth more than mere knowledge. This appeal to experience was sufficient, in any event, to give rise in post-Aristotelian philosophy to numerous affirmations of a broader empiricism: Stoics and Epicureans, for example, agree in deriving perception from the impressions made upon the soul by external objects. Thus skepticism originated and developed; in that empiricism it recognized the absence of a stable and secure criterion of truth, but only in order to conclude that it was necessary to remain with the facts, renouncing every scientific demonstration.
The question returned in modern times; indeed, it is precisely in the modern age that it became a fundamental problem for philosophy. Insofar, in fact, as modern philosophy, in agreement with the new physical science inaugurated by Galileo, reacted against the abuse of formal logic and the metaphysical speculations—sometimes also fantastical—of the preceding period, it assigned the greatest possible value to the world of human experience (the adjective here is not superfluous; on the contrary, it provides the most significant and polemical note of the new concept). But it would not for this reason be correct to define this philosophy as empiricist: on the contrary, it immediately revealed itself to be troubled by the effort to move beyond empiricism and to construct a new logic and a new metaphysics, capable of accounting for this world of human experience better than the traditional ones. Hence the discussions on method, in which the names of Bacon and Descartes are celebrated (the former more inclined toward the experimental aspect of the new physical science, the latter toward its mathematical and constructive aspect); and hence the attempts at a metaphysics founded upon consideration of man, who is soul and body, thinking substance and extended substance (Descartes), which Spinoza and Leibniz would seek to unify by different paths. Against this current, later called “rationalistic,” there arose in England (where precursors can be traced as far back as the period of scholasticism) the current more properly designated as “empiricist,” whose most eminent representative was G. Locke (1632–1704). He stated with complete clarity the presupposition from which modern philosophy proceeded—the world of human experience—and
consequently, in his opposition to innatism, he combated all those theories that admitted theoretical or practical principles not derived from that world and anticipated, in one way or another, prior to II. Hence his tendency toward sensationalism, without, however, falling into it, because he recognized the activity of reflection and, in addition to external sensation, posited internal sensation—that is, consciousness of the operations of our spirit—as another source of ideas. This tendency was subsequently developed and perfected by Condillac (1715–80), who attempted to unify the two sources in the single principle of sensation. Sensation first appears as an internal state of consciousness and then gradually draws from within itself the entire wealth of determinations concerning the real world of experience and reflection upon II. Meanwhile, Lockean empiricism underwent a profound criticism in England itself. Berkeley (1684–1753) began this process; proceeding from the principle that every sensation or perception is one of our states of consciousness, he denied the necessity of presupposing the existence of a material world—of “things”—outside us. But the thinker who carried the criticism to its extreme point was D. Hume (1711–76), who attempted to demonstrate that, since human knowledge is founded upon the ever-changing and contingent experience of the senses, we can affirm nothing about reality: neither what things outside us are, nor what we ourselves are. Nothing remains but a “flow” of sensations, among which it is impossible to establish any relation of necessity. Thus modern empiricism issued into the more radical form of (epistemological) skepticism. But from this, as is well known, Kantian criticism took its point of departure. It began by conceding that all our knowledge originates, in time, from experience; but precisely because experience alone cannot explain it, this means that implicit within it are principles (a priori), forms of sense and understanding that he calls “transcendental,” posited by the cognitive faculty itself in the act of appropriating the data of immediate experience (v. CRITICISMO; KANT).
After Kant, but especially after absolute idealism, which extensively developed the (transcendental) concept of the a priori in Kantianism, empiricism fell into disrepute: for many, it still means accepting the data of experience without criticism (without “philosophical” criticism, that is; for physical science too exercises a form of criticism upon the data of experience, but only insofar as it interprets phenomena objectively). In the second half of the last century, however, a reaction against absolute idealism arose, and empiricism attempted to reappear in new forms, developing that aspect of Kantianism by which it recognized the necessity, for the validity of our knowledge, of remaining within the world of phenomena, that is, of experience. An attempt was therefore made to demonstrate that Kant’s own a priori forms could be explained as a product of psychic associations, or as properties implicit in every sensation, from which it would suffice to extract them—without any need to presuppose them—and so forth. Associationism, phenomenalism, positivism, empiriocriticism, etc., thus sought to take up again the empiricism preceding Kantian criticism in new forms. People even spoke of “pure experience” and of an “absolute empiricism,” to indicate a consideration of experience that would resolve within itself all the principles introduced by Kantian criticism and idealism itself in order to explain II. In truth, however, the classical period of empiricism remains the pre-Kantian period, when its strength, however naïve it still was, possessed the greatest fascination of novelty. Today we may say this:
Unt. Alinari