Descartes’ Philosophy: Methodical Doubt & Reality
Cogito, Ergo Sum: Methodical Doubt and First Truth
René Descartes posited that everything should be doubted until proven without a doubt. Cartesian methodical doubt provisionally considers all knowledge as potentially false. This doubt extends to several areas:
- Knowledge from the Senses: We can doubt that things are as they appear, though their existence may still be possible.
- The Existence of Things: It’s difficult to distinguish waking from dreaming, making the existence of things uncertain.
- Mathematical Truths: Descartes introduces the hypothetical ‘evil genius’ to cast doubt even on mathematical truths.
Cartesian methodical doubt becomes universal, encompassing all knowledge. However, the assertion cogito, ergo sum (“I think, therefore I am”) emerges as the indubitable truth Descartes sought. Any act of doubting, supposing, or being deceived confirms the existence of the doubter – the “I”. This cogito becomes the foundation for all knowledge and the first cornerstone of Cartesian philosophy.
Ideas in Cartesian Philosophy
An idea, for Descartes, is the general form of a thought, the immediate perception of which makes one aware of that thought. Each idea has both a subjective (mental) reality and an objective reality. The cogito assures us that ideas exist within thought, as actions of the thinking subject. Descartes distinguishes three types of ideas:
- Innate Ideas: Conceived by thought itself, representing the true and immutable essence of things.
- Adventitious Ideas: Ideas that seem to come from outside, appearing foreign to the mind. These include ideas of natural things.
- Factitious Ideas: Constructed by the mind from other ideas.
God and the World According to Descartes
The idea of God, for Descartes, is the idea of an infinite, eternal, omniscient, omnipotent creator. He argues that this idea is innate. From this, Descartes demonstrates:
- The Existence of God: If God did not exist, the mind could conceive of something more perfect: a being with God’s attributes *and* existence. He also uses a causal argument, stating that the *idea* of God implies God’s existence.
- The Order and Existence of the World: God serves as the second cornerstone of Cartesian philosophy, guaranteeing truth and order.
The Structure of Reality: Cartesian Ontology
Descartes identifies three types of reality:
- Infinite Substance: God.
- Thinking Substance: The mind (res cogitans).
- Extended Substance: Matter (res extensa).
A substance, for Descartes, can exist independently. Cartesian dualism arises from the division of the world into thinking substance and extended substance. Res extensa possesses primary qualities (inherent) and secondary qualities (subjective). The reduction of embodiment to extension forms the metaphysical basis for the mechanistic nature of Cartesian physics.
The Human and the Soul: Cartesian Anthropology
The soul is the non-extensive, intangible res cogitans, or thinking substance. Descartes’ conception of humanity is dualistic, comprising both material and immaterial substances. The union between soul and body occurs in the brain, specifically in the pineal gland. Leibniz later proposed the theory of pre-established harmony, suggesting that the soul and body, while independent, function in unison.
Descartes believed in free will. In correspondence with Princess Elizabeth of Bohemia, he maintained that while God foresees and predetermines human actions, He does not determine human will. The problem of error, in Descartes’ philosophy, is directly linked to the issue of freedom. From a practical perspective, freedom connects to his theory of passions. He distinguishes between:
- Actions of the Soul: Dependent on volition.
- Passions: Involuntary perceptions, feelings, or emotions caused by mechanical forces acting on the body.
Joy and sadness are considered the most important passions. The gradual mastery of passions allows for the integrated use of free will and reason. The domain of passion is, ultimately, the domain of desire.