Descartes’ Rationalism: Socio-Historical Context & Features
ITEM 11: The Modern Continental Philosophy, Descartes’ Rationalism
1. Socio-Historical Context
René Descartes, the creator of Rationalism, lived in the seventeenth century, the Baroque era. This period was marked by events of great importance but also by crises, including ideological, social, economic, political, and religious upheaval.
2. Features of Rationalism
- Self-sufficiency of reason: Reason is considered the justified source that produces knowledge and the only valid way to understand and explain reality.
- Innate ideas: These are the ideas from which all knowledge is built.
- Deduction: Descartes proposed that rationalist philosophers use the deductive method, similar to that of mathematics.
3. Influence of Math on Descartes
Descartes’ philosophy tries to achieve objectivity and accuracy similar to that of mathematics, aiming to be a science (i.e., establishing universal truths, necessary and indubitable). He proposed using the deductive method of geometry.
4. The Need for a Reliable Method
Descartes believed that when investigating, a person might unwittingly be carried away by emotions, prejudices, or interests. To avoid this, he proposed the Cartesian method, a set of rules for the appropriate use of natural capabilities and reason, intuition, and deduction:
- Intuition: Direct uptake of a purely rational reality, free from doubt and absolutely true.
- Deduction: Uptake in indirect steps, a general proposition drawn from a more specific one. It is a succession of intuitions.
The rules of the Cartesian method are:
- Rule of Evidence or Cartesian criterion of certainty: Only accept as true the idea that is presented in a clear, distinct, and unmistakable manner.
- Step 1 – Analysis or decomposition rule: Divide the object to examine into as many parts as possible to reduce it to simple and basic natures that can be grasped intuitively.
- Step 2 – Regulation of the synthesis or composition: Compose the object again from the pieces to understand their roles and skills, from the simple to the complex. The deduction is made.
- Step 3 – Rule and synapses list: Make a list and review the steps above for errors.
5. The Search for a True First Through Doubt
Descartes stated that human reason had to find a first absolute and unquestionable truth from which to build the whole edifice of knowledge. He used the Cartesian methodical doubt, tentatively doubting everything. He proposed three reasons to doubt our knowledge:
- The senses deceive us and mislead us, so the knowledge they give us is not entirely reliable.
- Inability to distinguish waking from sleep, as both can perceive the same things.
- Existence of an evil spirit (evil genie) that tricks us, undoubtedly causing mistakes in mathematical ideas.
This seems to lead to skepticism, an aporia, until at last, he found the first truth. Descartes could doubt everything except that he doubted. To doubt is to think, and to think it is necessary to exist; hence the famous phrase, “I think, therefore I am,” reaching it in a clear and distinct, intuitive way. Thus, he accepted it as absolute truth and the first principle of his philosophy, hence the rule of evidence.
6. Ideas as the Object of Thinking
Descartes says that thought thinks ideas; one does not think directly in the world but on the idea one has in their mind of that world. He distinguishes three types of ideas:
- Adventitious ideas: Those that appear to come from the experience of external objects.
- Factitious ideas: Those built with the mind from other ideas (e.g., a winged horse).
- Innate ideas: The primitive ideas God gives us, from which the rest of knowledge is built.
7. The Existence of God and the World
One of the innate ideas is the idea of infinity, identified with the idea of God: God = Infinite. This idea serves to prove God’s existence in various ways, remarkably demonstrated by the ontological argument (= Saint Anselm): having the idea of God, we realize that God has existence in its very essence as one of its perfections. Therefore, we cannot define God as excluding the existence of its perfections.
To attempt to prove the existence of the world, Descartes starts from the existence of God because if God exists and is infinitely good, God cannot allow me to fool myself into thinking that the world exists, so it does.