Rationalism: Descartes and the Primacy of Reason
Rationalism
The continuing problem throughout the Middle Ages had been tension between Faith and Reason. For St. Augustine, they were totally together: faith is required to reach the truth, which is God.
Definition and Characteristics
In general, we say that classic rationalism is a philosophical current of the seventeenth century. Descartes belongs to it, in contrast to the current of eighteenth-century empiricism represented by Locke, Berkeley, and Hume. We can define rationalism as:
- Self-sufficiency of reason as a source of knowledge.
- Negatively: the exercise of reason cannot be abridged by any higher court, neither tradition nor faith nor authority.
- Positively: reason is the supreme principle which is required to judge the truth. It is only reason.
These features are common in modern thought to any of the philosophical movements, not only to rationalism. It opposes sensitive knowledge. Specific definition: It is the philosophical doctrine that explains the origin of knowledge:
- Empiricism: Knowledge comes from the senses, of sense experience.
- Rationalism: Valid and true knowledge about reality proceeds from reason, from the understanding.
Science: If science is built upon certain ideas and principles, whence come these ideas and principles?
- Empiricism: Knowledge comes of sense experience.
- Rationalism: They are innate to understanding: that it possesses in itself, regardless of any sensible experience.
Characteristics:
- Confidence: There is total confidence in rational knowledge.
- Sensitive: Underestimation of sensitive knowledge. The senses lead us to deception and error.
- Innate: Affirms the existence of innate ideas in the mind, regardless of experience.
- Science: Affirms the need for necessary and universal science: mathematics.
- World: Defends the rationality of the world.
Lack of Rigor in Philosophy
From the strictly philosophical standpoint, rationalism is the dominance of reason over sense experience in knowledge.
The Need for a Method
Philosophy must be sought only true, universal knowledge, valid for all, both in theoretical and practical knowledge that out of life.
- Intuition: Search for truisms, indubitable, that in no way can be denied, as that 2 + 2 = 4, or that the angles of a triangle sum two right angles. They are like axioms that are not provable (Rule 3 a).
- Deduction: It is a “necessary conclusion derived from all other things known with certainty” (Rule 3 a). Conclusions are secure, stable, certain, efficient, allowing us to demonstrate rigorously other truths.
René Descartes (1596-1650)
Life and Works
Born in 1596 in Touraine, of a noble and wealthy family that allows him to study. He moved to Holland in 1629, where he is accused of atheism and sentenced. His head is the spirit of philosophy.
Works:
- Rules for the Direction of the Mind: Incomplete. Written in 1628 and published in 1701.
- Treatise on the World: Built on the hypothesis of Copernicus, he waives its publication on the news of the sentence of Galileo.
- Discourse on the Method: 1637.
- Meditations on First Philosophy: Written in 1640.
Philosophical Itinerary
Philosophical Disappointment
The first step in his philosophizing is given to disabuse of studies. He feels tortured since his youth for having accepted a series of truths as certain, without having checked them personally. He was dismissed from the Jesuit college of La Flèche with deep disappointment in most of the sciences, except mathematics. He leaves school dedicated to “read the great book of the world, traveling…”
Method
As the need for a more accurate method is the mathematician, this should be the favorite: Everything that we do get through the deduction of a certain truth to other truths. So it may sound philosophical construct a building like a real tree of knowledge, based on a foundation.
The Method of Descartes
Starting Point: Doubt
Descartes wants to distinguish truth from falsehood and to find a solid foundation of certainty, that is a clear and distinct idea. But to get absolute certainty, one must begin doubting.
What is the question?
- Universal: One must doubt everything, be subjected to doubt all the certainties that had until now from all the philosophical principles on which it was based.
- Methodical: Cartesian doubt is not skeptical doubt: it does not propose a demolition order, but constructive: it aims to reach the truth, a truth which no firm can doubt.
- Theoretical: It should not extend to the level of beliefs or ethical behavior, only to the level of theory or philosophical reflection.
- Doubt of the senses: Sometimes they deceive us, mislead us, therefore we do not trust them.
- Doubt of the outside world: If it is sometimes impossible to distinguish external reality from the dream, how can we be certain that it exists outside world?
- Doubt of own reasoning: My understanding can be wrong when he argues, even mathematical proofs themselves.
- Self-doubt: Is it possible that I have a kind of “brownie” internal to me, an evil spirit who misleads me?
Descartes intends to reach a truth that can be believed by itself, independent of any tradition or authority. And a truth, moreover, can be derived from other truths.
The Rules of the Method
“For method see,” says Descartes, “certain rules and easier than making it impossible to take as true what is false and… without wasting uselessly the forces of reason, science makes progress gradually to reach true knowledge.”
- Evidence: Do not accept anything that is doubtful. Do not rush, we must admit only that which is presented to our intelligence so clearly that no mistake is made.
- Analysis: The only evidence we have of simple ideas. As girls are highly sweetened to do is to reduce the composite ideas to simple ideas.
- Synthesis: Once the concepts have become compounds of simple and intuitive ideas… we must return to recompose through synthesis.
- Enumeration: It is through the entire process to be sure not to omit anything. It is the verification of the process to obtain a general insight into its simultaneous evidence.
The whole method reduces to the evidence: evidence must be achieved in the first truth where others are deducted (the idea clear and distinct); evidence must be achieved in the process and must be achieved in all the evidence of the process.
Results of Doubt: The “Cogito”
With doubt, Descartes has swept all opinions, has suspended all certainty, all but the truths of faith and moral standards “to follow housing-do”… Everything else has been in doubt. Cogito ergo sum. I can think there is no God, there is no world, things… But I, I think these things do not exist at the same time as I think. In Descartes’ cogito ergo sum principle is sought. The clear and distinct idea. The firm foundation to build the whole edifice of philosophy, a great base that will serve as a basis to infer from it all other truths.
Analysis of the “Cogito Ergo Sum”
There are two clear elements: thinking and existing.
- Thinking: For Descartes is not a purely mental act: it is a combination of things.
- Exist: Descartes starts from their own interiority, of the thoughts that he discovers in himself, and from there comes into being: the “I” as a thought that exists.
The characteristics of the “cogito” might be these:
- There is a syllogism: The syllogism is: “Anyone who thinks there is, I think, therefore I am.”
- It is not a clear and distinct idea: It is an idea that is imposed with immediate evidence, without any reasoning.
- An immutable truth: It is a truth that can not be doubted. In it, he wants to settle all the building of philosophy. It is the first trial and obvious, absolutely true and more secure.
Analysis and Classification of Ideas
From the former mental process, Descartes has found a firm footing to construct the whole philosophy: the “cogito” is a clear and distinct idea: it admits no doubt, and it can be deduced from other truths, as happens in mathematics.
- Clear: Manifest without darkness, without difficulty that intuits intelligence.
- Distinct: That is separate from any other idea, which itself contains no other ideas, i.e. that is simple, elemental.
The classification of ideas that Descartes makes is this:
a) Adventitious Ideas: Those that appear to come from our external experience: such as things, men, etc. And we know the existence of a reality exterior.
b) Factitious Ideas: Those that come from our imagination and will: be built from these two faculties.
c) Innate Ideas: If you can not come from outer experience, neither of their own mental construction, even if apart from other ideas.
Reality in Descartes
Descartes has found ideas and a certain criterion to distinguish the true from the false. Descartes used as synonyms the words “substance” and “thing” (res), i.e. the substance is the concrete existing.
The Origin of Substance
As we have seen, from the “cogito”, Descartes deduced the substance and the three realities or substances or things are these:
- Res Cogitans: I’m just a thought, a thing that thinks, a thinking substance, a thing that exists in such a way that does not need anything else to exist. My body does not need to think to exist.
- Res Infinitia: The thinking being that thinks, that is certainly imperfect (more perfect would be not to doubt), and this imperfection is calling for a perfect, infinite, and this is God.
- Res Extensa: The thinking being must be corporeal and all bodies have extension.
Thinking Substance or ‘Res Cogitans’. Cartesian Anthropology
A thinking substance called the soul. The soul exists, independent of the body. This independence of the soul to the body tries to save Descartes to defend the freedom of man. Body and soul are two separate substances that can exist without the other: the soul is a substance that thinks; the body is a substance extended in the abstract: the “I” that thinks is a reality that is split in two: body and soul. The body must be understood as constituted by matter, filled space. The soul must be understood as a spirit, made by thought, as something quite distinct from the body and does not need it to be, to think, thought is independent of matter, body, senses. The coordination of these two realities is carried out by the pineal gland, that part of the brain where the soul feels especially its efficacy to all parts of the body.
The Infinite Substance: God
Where does the idea of infinity come to me from?
- It does not come from nothing, from nothing comes nothing.
- It does not come from myself: I am finite and the finite can not come the idea of the infinite (or rather would be reversed); admit this is the same as admitting that nothing comes from something.
The Physical World or the ‘Res Extensa’
We perceive the world, physical things, bodies, and things that have length, is the attribute of the corporeal substance. Descartes proves the world’s existence from the existence of God.
Conclusion: There are three innate ideas which we conceive clearly and distinctly:
- The soul: thinking substance.
- God: infinite substance.
- The material substance: extended substance.
Other Representatives of Rationalism
Rationalism: The origin of knowledge is in reason. The understanding has innate ideas prior to experience. From these ideas, without experience, we can derive all our knowledge.
Empiricism: The origin of knowledge is experience. No innate ideas: the understanding is understood as a blank page.
Empiricism is the forerunner of Bacon and somehow starts with Locke (1632).