Descartes and Spinoza: Rationalism, Method, and Substance
Descartes’ Method: A Foundation for Rationalism
Descartes believed the success of his method stemmed not only from its inherent perfection but also from his understanding of human reason as a faculty capable of addressing and resolving complex questions. His method is based on four rules:
- Evidence: Accept only what is clear and distinct.
- Analysis: Divide complex problems into simpler parts.
- Synthesis: Systematically build from simple to complex.
- Enumeration: Thoroughly review to ensure nothing is omitted.
Doubt and the First Truth
Descartes advocated questioning all received knowledge to discover indubitable truths. His famous method of universal doubt rests on these principles:
- The Uncertainty of Sensory Data: Doubting the reliability of information from the senses and the material reality of the world.
- The Errors of Reasoning: Questioning the validity of even demonstrative reasoning.
- The Difficulty Distinguishing Dream from Reality: The possibility that all thoughts are dreams we fail to recognize as such.
- The Hypothesis of the Evil Genius: The notion of a deceiving entity that makes us doubt even the most obvious things.
Descartes’ doubt is not skeptical doubt; it is a provisional doubt that aims to overcome itself. The famous “Cogito, ergo sum” (I think, therefore I am) arises from this: the very act of thinking and doubting proves one’s existence, making it the first unquestionable truth.
The Three Substances
Descartes identifies three distinct substances:
- The Thinking Self (Res Cogitans): The ‘I’ that thinks, encompassing all thoughts, ideas, and subjective representations.
Descartes classifies ideas as:
- Adventitious or Acquired: Ideas derived from sensory experience.
- Fictitious or Artificial: Ideas we invent ourselves.
- Natural or Innate: Ideas that seem to come from within, not from external objects.
God
Descartes acknowledges his imperfection but recognizes the idea of perfection within himself. He argues that this idea of perfection, the idea of God, must be innate. According to Descartes, this idea cannot originate from imperfect beings like ourselves; it must come from a perfect, divine source. The demonstration of God’s existence is crucial to Cartesian metaphysics. God serves as a guarantor of knowledge, ensuring the reliability of clear and distinct ideas. God’s eternal existence underpins all truths, including mathematical truths.
Spinoza’s Rationalist Spirit
Spinoza, inspired by modern rationalism, embraced the mathematical method of Descartes. He developed a deductive system of reasoning, believing that mathematical rigor allows us to reach reality with greater accuracy. His geometric method begins with definitions and axioms, from which theorems and corollaries are deduced. Spinoza sought to provide genuine knowledge, knowledge of causes.
Monism and Substance
Spinoza’s concept of substance begins with a definition that leads him to conclude that there is only one substance: God, which he identifies with nature. Spinoza distinguishes between natura naturans (creating nature, i.e., God as infinite substance) and natura naturata (created nature, the set of all individual realities). Spinoza equates God with nature, asserting that creation is a natural necessity.
Happiness and Ethics
Spinoza posits that we are both body and soul, known through God’s attributes. All beings are created equal and, by nature, tend to persevere in their being. Humans strive not only to survive but also to achieve tranquility through adequate knowledge. Virtue lies in living under the guidance of reason, aligning with our inherent nature. A happy life consists of having adequate ideas, and happiness is linked to understanding, which frees us from the weight of passions.