Idealists and Materialists of Modernity

The Relation Between the Truth of Philosophy and the Certainty of Knowledge

The imagination, as described by Descartes, is sufficiently passionate to encompass the reasons for the extension of things, yet it is also rational enough to allow for an understanding of the limitations of human reason concerning its material origins. For instance, when imagining a unicorn, we envision it vividly, yet we do not conceive of seeing it through our nose, ear, or liver; similarly, even if we suddenly imagine a "seeing liver," we would not think of it primarily as being meant for perceiving imaginary unicorns. Thus, it appears that the imagination, however far it may lead us away from both things and thoughts, can only explain why we see with our eyes and perceive what we see with our minds. As we can observe, Cartesian imagination diverges from previous notions of imagination as an exploration of a comprehensible model, as was the case in classical rhetoric.

Yet, another difficulty arises: if our knowledge of bodies corresponds to a clear and distinct idea of a body in general—a strictly geometrical idea—why do we see an apple rather than a sphere, a plate instead of a circle? Does it not follow that the essence of things, which is more geometrical than composed of random details, is concealed from us? Descartes initially proposes that ideas of things are directly instilled in us by God and correspond to things as mere hints. This assumption is drawn from scholasticism, where the term "virtual" denoted "possible," implying a relation to things that does not reveal their essence but merely alludes to them. Hence, all ideas are "virtual," yet it remains unclear from where the idea of our own reality, including the reality of our correlation between ideas and things, originates. Consequently, Descartes posits another hypothesis: that things are imperfect likenesses of ideas, and that an apple or a ball is a poor copy of a sphere. But this leads us back to a notion we sought to escape—the deceiving God who misleads us by presenting ideas as arising from things, even though the idea of truth, for instance, cannot stem from individual things.

As we can see, Descartes' reasoning here becomes somewhat timid and even convoluted. Not all Cartesian thinkers accepted his views, just as later many philosophers inheriting from Kant rejected his concept of the "thing-in-itself," insisting instead on substance as a unit of knowledge rather than merely a unit of existence. Nicolas Malebranche (1638—1715), for example, believed it was simpler to relinquish the notion of things than to tackle a problem with three unknowns: God, ideas, and things. From Malebranche's perspective, the ability to assert "the apple is round" belongs entirely to our minds; without our minds, we would not even identify an apple, considering it merely a growth on a tree, with the tree as a growth on the earth. All things would vanish for us. Thus, Malebranche argues, only the existence of God and our minds can be deemed certain, while all other things are merely aspects of the mind's activity or divine revelation. Ultimately, we must acknowledge the existence of bodies, but only because Revelation (both in the biblical text and in the effects of receiving revelation, such as the fire that tests those initiated into prophecy) compels us to accept such existence.

Malebranche, who attempted to unify Cartesianism with Platonism, asserted that any thing is a substance, and any mind is also a substance. Everything else is merely a mode of existence of one substance or another. However, he then encountered a difficulty: for any thing is divisible, and the parts of a thing also exist in some manner, which implies that these parts must be recognized as substances, ad infinitum. For instance, we can decompose a table into its top and legs, and these parts can be further divided into surfaces and angles, and so forth into mathematical and geometrical indicators. It follows that anything could be deemed a substance, and we might only be able to study modes of existence. Malebranche did speak of natural laws applicable to certain classes of things, but this was merely a partial resolution to the issue. Malebranche's doctrine is often referred to as "occasionalism," in other words, a doctrine of occurrences: one can study only how something occurs, not how something exists.

Another idealist thinker, George Berkeley (1685—1753), went even further, asserting that Revelation does not compel us to believe in the reality of things. For instance, the Bible states that God created certain things. However, to create does not necessarily mean to make things such that they are substantial or lead to discord in their existence. It is simpler to think that things were created as our representations, as what is perceived by our "intelligences," predispositions to understanding. The assumption of the coarse materiality of things only hinders these predispositions, and a "veil" of matter is unnecessary where the human mind seeks to resemble the divine mind. Berkeley’s central formula is, “To be is to be perceived or to perceive,” and if we do not recognize a thing as perceiving everything around it, then it suffices to acknowledge that it is perceived.

Let us briefly consider the terms themselves. The word "matter" originates from the Latin term for "forest" or "wood," mirroring the corresponding Greek term. The Greeks, as shipbuilders, understood well that art cannot be created merely from available materials; it is essential to select the appropriate timber for a ship, as we say. There was even the paradox of the ship of Theseus: as it gradually decayed and its rotten planks were replaced with new ones, until all had been substituted, the question arises: is the vessel before us the same as it once was, if all its matter is now different? In antiquity, there were no pure materialists who derived all existence from matter, just as there were no pure idealists who derived all existence from ideas. For instance, Democritus or the Epicureans seemingly taught that everything consists of atoms, yet atoms were forms with their properties and intellectual characteristics. Similarly, the idealists: followers of Plato saw in things a faint reflection of ideas, while in matter, they recognized merely a space or a rather insignificant original material (the "chora," as Plato termed it, meaning simply "place" or "locale"), but Plato also spoke of a demiurge, a creator, and it is clear that he could not do without matter entirely. Only a poet creates what did not previously exist, but the demiurge is not a poet but a craftsman.