Problems of Epistemology

The Problem of the Origin of Knowledge

Rationalism

The question of the origin of knowledge gives rise to the opposition between rationalism and empiricism or sensationalism. Empiricism derives all knowledge from perception, while rationalism, on the contrary, asserts that scientific knowledge cannot arise from the senses; it possesses universality and necessity, and thus is the product of reason. I shall attempt to elucidate the significance of both theories and my own position regarding them in the form of a historical exposition.

The viewpoint of common opinion on this matter—assuming it can even be spoken of—most closely aligns with sensationalism: our knowledge of things originates from sensory perceptions. As soon as philosophy separates itself from common opinion and begins to set itself against it, the rationalist theory emerges immediately. Philosophy claims a different origin for itself than that which it acknowledges for common opinion; while the latter indeed derives its knowledge from the senses, scientific knowledge or philosophy does not arise from perception but from thought or reason.

This consensus is found among all the early great systems of Greek philosophy. Regardless of their differing views on the essence of things, they all agree that truth does not originate from the senses. Thus, Heraclitus rebukes the senses: the eyes and ears of those who lack the language of knowing souls serve as poor witnesses, implying that only those who can interpret their testimony with critical reason truly learn through the senses. Even more sharply, the philosophy of the Eleatics denies the truth of the senses and common opinion; truth resides solely in reason, while the senses produce only deceptive appearances, presenting the one and the essence as the many, the mobile, the emerging, and the transient. Zeno attempts to demonstrate through reason the inconceivability, hence the impossibility and invalidity of the sensory world. Similarly, the two other oppositional figures, Democritus and Plato, concur that only reason leads to truth, not perception. Indeed, the senses cannot perceive either atoms or ideas; these can only be seen by reason, which penetrates through the diversity of appearances to the ultimate foundations, to the truly real.

Likewise, the first major systems of modern philosophy are rationalist in their theory of knowledge—Descartes, Hobbes, Spinoza, and Leibniz. They begin with mathematics; mathematical physics, and ultimately the mathematical theory of the world is their aim. Certainly, neither of these, as well as pure mathematics, can be constructed through perception or experience. Additionally, there is another circumstance: modern philosophy, at least among some of its proponents, must also serve, like the old scholastic philosophy, as a rational theology to demonstrate the existence of God and the immortality of the soul; for this, experience is certainly insufficient. This relationship has granted the rationalist theory of knowledge the reputation of benevolence, while empiricism remains suspected of a nefarious direction; even now, at least in Germany, it is common to hear that empiricism leads to materialism and atheism.

Rationalism, then, is the first form of the scientific theory of knowledge; it was created by the great metaphysical systems as their epistemological justification. Empiricism, of a later origin, arises as a critique of metaphysical systems and their theories of knowledge. First, I will outline the fundamental features of the rationalist theory. Thus, its assertion is as follows: all present or scientific knowledge is produced by reason through immanent development from initially certain principles, rather than derived from perceptions or subject to empirical verification. The model of this method is provided by mathematics. Here two questions arise, and their answers constitute the essence of the theory of knowledge in rationalism: 1) How do we arrive at these first principles, these absolute starting points of knowledge? 2) How is it that such a system, constructed through rational activity, yields objective knowledge of reality? For the intention of any science remains the depiction of reality; yet it is evident that the agreement of such an a priori system of thoughts with the actual world is by no means self-evident and, in fact, quite unexpected.

Three fundamental forms of rationalism can be distinguished; they differ from one another in their responses to both of these questions: metaphysical rationalism, mathematical rationalism, and formal rationalism. Plato, Spinoza, and Kant may serve as representatives of these three fundamental forms.

Metaphysical rationalism rests on the assumption that reality itself is thought; therefore, it can be known through pure thought. Plato, prepared by the speculations of the Eleatics, was the first to establish this idea as the foundation of a grand philosophical system. His firm point of orientation is the conviction that the world of sensory perception is not the actual world. Reality in itself is a system of concepts or thoughts; the world of ideas. How do we come to know it? Plato’s answer is not strictly epistemological but forms part of his metaphysics: the soul is something that possesses an inherent affinity with truly real existence. It is itself thought or spirit, in its essence or in its present form. In its earthly existence, it does not manifest as what it truly is—pure thought; here its essence is cloaked or distorted by the admixture of sensory perception and desires. However, this earthly life is but one phase of its being; it existed prior to incarnation and will continue to exist after separation from the body. In its incorporeal existence, it is truly what it is, and here it stands in immediate communion with the truly real, contemplating ideas, that is, thinking thoughts that are thoughts. In bodily life, its thinking is darkened by sensuality. As people, so says the famous allegory in the "Republic," sitting chained in a cave with their backs to the exit, see the shadows of things passing on the back wall, which are moved outside before the entrance, so the soul sits in the cave of the body and sees all kinds of shadows of things, cast there through the openings of the body—the eyes and ears—by the moving objects. In any case, it retains a faint reflection of true thought, as a memory from that state of incorporeality and clairvoyance. Thus, its task in this life is to liberate, as much as possible, thought from the sensuality that has obscured it with the illusory and the deceptive. Mathematics and dialectics—two great forms of thinking in concepts—serve as the means to this end.

I shall not delve into a critique of this rationalism, nor into the nascent approaches toward an empiricist theory of knowledge found in Aristotle. The latter, however rigorous and often unjust a judge of Plato he may have been, could not create a coherent alternative: his empirical theory, arising from observation, and his rationalist theory, stemming from syllogistics, remain irreconcilable side by side. On the contrary, I wish to point out how the Platonic view has been renewed in the speculative philosophy of our century. In Hegel, we find the same fundamental viewpoint: reality is itself thought, developing with internal necessity as an idea; perfect knowledge consists in the thinking of actual thoughts; in the dialectical movement of philosophical thought, the essence in living self-motion repeats, or rather encompasses itself with self-consciousness as the absolute idea.

The second form of rationalism is mathematical rationalism of the seventeenth century. It differs from the Platonic one in that it remains immanent. Its assertion is this: every science, especially and foremost the natural sciences, can and should take the form of mathematics, i.e., the form of a demonstrative system derived from principles. Descartes and Hobbes converge in this fundamental assumption; Spinoza, in his "Ethics," attempted a formal presentation of it; Leibniz, already grappling with the emerging empirical critique, endeavored to retain it with certain limitations.

The response to the two aforementioned questions of rationalism unfolds in the following manner. To the inquiry concerning the nature of the first principles of demonstrative knowledge, Descartes does indeed respond with the expression: these are innate ideas. This expression finds its roots in Platonic philosophy; however, it is merely an old name, not an old meaning. Descartes does not entertain any notions of the pre-existence of the soul or memories. What he implies is that there exist certain elements of knowledge that are initially produced by the intellect and do not require any confirmation through experience. Mathematics illustrates this well. Its foundations are definitions and axioms; the truth of both is not based on perception or experience. Mathematical definitions are concepts that are absolutely posited by the intellect; it furnishes the concept of a circle and a tangent, degrees and logarithms, observing solely its own function rather than any given perception. Likewise, axioms are propositions whose truth is not established by experience, but which, once grasped by the intellect, are immediately recognized as self-evident.

Thus, this constitutes the very form of science. Primarily, this holds true for physics; it is, in essence, nothing more than a branch of mathematics. Cartesian philosophy stands at the forefront of the endeavor to demonstrate the feasibility of a purely mathematical physics. Consequently, the essence of the body is reduced to pure extension; it possesses no other definitions aside from geometric ones, no internal definitions; thus, it submits entirely to the mathematical method. "Corpus est res extensa": this is a mathematical definition, just as is the definition of an angle or a circle. The same applies to the concept of the soul: "mens est res (mere) cogitans." Now, there are also axioms to consider, such as the principle of the conservation of substance: the quantity of matter neither increases nor decreases; or the principle of the conservation of force: the quantity of motion remains unchanged; there is neither creation nor destruction of motion, only the transfer of motion from one body to another. Based on these definitions and axioms, it is now required to develop natural science as a demonstrative system of mechanics. In this context, the significance of perception is akin to that in geometry: it may provide the initial impetus for the formation of concepts and propositions. However, only in demonstrative proof do we acquire true, complete science.

This also provides an answer to the second question: whence arises the accord of such a purely immanently developed system of theorems with reality? Descartes answers: just as mathematical concepts guarantee their truth within themselves and require no confirmation through experience, so too do these definitions. He articulates this view in the form of a general proposition: what I perceive clearly and distinctly is true. Every clear and distinct concept possesses its guarantee of truth precisely in its thinkability or possibility; "quidquid clare ac distincte percipio verum est"—a statement that evidently reveals its origins in mathematical thinking.

This perspective is thoroughly manifested in the philosophical system of Spinoza. "Ethica more geometrico demonstrata"—thus declares his principal work. Here, the mathematical form is consistently applied; all sciences—metaphysics, physics (outlined in the second book through several lemmas), theory of knowledge, psychology, ethics, along with the foundational concepts of political science—are treated according to a geometric scheme. Each book commences with definitions and axioms; subsequently follow theorems and proofs, corollaries and scholia; all philosophy constitutes a system of necessarily valid formulas derived from necessarily valid concepts and axioms. In response to the question regarding the accord of this system with reality, Spinoza draws from his metaphysics. The parallelism of the two attributes, thought and extension, is employed to substantiate the theory of knowledge: the same essence of substance or the all-active manifests itself in the system of modes in both the corporeal world and the world of thoughts. Therefore, the order and connection in the world of thoughts correspond to the order and connection in the corporeal world; what is here the cause and action is there the ground and consequence: "sequi" and "causari" (to logically follow and to be caused) are, in essence, one and the same.