Descartes’ Quest for Certainty: Mind, Reality, and Knowledge
Descartes’ Meditations: Doubt and Existence
The Problem of the Evil Genius
Part of the nature of the human spirit is to question the body’s reality. Considering all doubts, false perceptions, and opinions, one might conclude that we have no senses and no kind of reality. In his Meditations, Descartes repeats this deduction to resolve some emerging contradictions.
This apparent contradiction arises in the concept of the evil genius: if God is infinitely good and infinitely powerful, it seems impossible for an evil genius to exist and deceive us. However, the contradiction emerges when Descartes states that this genius sometimes deceives him. If I am deceived, then the evil genius is still there, making me be deceived. Therefore, if I am deceived, it means that I exist, because I must first exist to be deceived. Thus, “I am, I exist” is a necessarily true proposition.
The “I Am, I Exist” Proposition
Now, one might think this is already clear, but let’s revisit Descartes’ proposal and examine it further. Consider the proposition “I am a man.” But what is a man? And how can the body, which does not move by itself and has no power of movement, be central? From this, he concludes that the body is not the most important, but rather the self.
With the affirmation “to think is to exist,” he deduces the res cogitans, i.e., the thinking thing (thinking substance), and states that thought is its primary attribute. From this, Descartes deduces the attributes of the self.
The Nature of Self and Reality
Distinguishing Res Cogitans and Res Extensa
Regarding the properties of the body—its shape, extension, movement, and other attributes that are not fictions of my mind—Descartes refers to the body as limited, without an inherent principle of movement, without a fixed figure, finite, without extension (in the sense of being a pure thought), and thus without a specific place, akin to a machine or an automaton. Descartes posited that the res extensa (the material world) might be an imagination that does not truly exist, and therefore our senses could deceive us, showing us a different reality. However, he also considered that some perceptions might be true and not deceptive.
The Deceptive Nature of the Senses
On the other hand, there is something that thinks: that doubts, understands, affirms, denies, wills, does not will, imagines, and feels. All these are functions and attitudes of the self that Descartes sought to develop. The senses are the only ones that can deceive.
Moreover, the spirit possesses characteristics such as understanding and reason, which are attributes of the soul (anima). The body, in contrast, has shape, extension, and movement, but does not inherently possess a ‘place’ in the same way the mind does.
Philosophical Comparisons
Descartes vs. Plato on Sensory Knowledge
According to Descartes’ conception of the role of the senses in the justification of knowledge, the senses are part of the res cogitans (the thinking thing). However, these senses can sometimes deceive us, just as the evil genius exists despite God being infinitely good and infinitely powerful and allowing us to be deceived at times. Thus, not everything perceived is always true; sometimes it will mislead us.
This conception of Descartes can be compared with that of Plato. Plato held the opposite view: to attain true reality, one must first separate the body from the soul (anima), as the body, with its desires and sensory perceptions, entirely deceives us. (This contrasts with Descartes, who states that the senses sometimes deceive us and sometimes do not.) Only when the body is finally separated from the soul (after death) do realities become complete and absolute, free from doubt or deception.
Rationalism and Empiricism: Views on Truth
Modern philosophy is characterized by two separate currents: rationalism and empiricism. Rationalism postulates the principle of reason, emphasizing the relationship between reason, reality, and existence. In contrast, Empiricism maintains that origin and experience are the limits of human knowledge, believing something is true only if proven scientifically.
From a rationalist perspective, one might argue that we cannot doubt what we feel, for instance, “I am doing a test and I am not a brain in a lab properly stimulated.” However, a rationalist might also question whether what I perceive or what my senses convey is truly real, as senses can deceive us, showing us illusions or mere imaginations.
In contrast, in Empiricist philosophy, such a statement could be considered true. After proper calculations and drawing a conclusion, one could affirm, “I have hands and arms, and now I am doing a test and I am not a brain in a lab properly stimulated,” because it is proven true and aligns with what can be scientifically verified.