Rene Descartes and DeductionJune 27, 2021
Aristotle’s classical form of reasoning, called syllogism (qiyas), constitutes the most typical example of deduction. Accordingly, syllogism is to draw the necessary conclusion that can be deduced from the given universal and general premises. If the premises are true, the conclusion is also true. Otherwise, the necessity of the result will not bring the accuracy of the result.
In mathematics, on the other hand, conclusions deduced from premises known as axioms or postulates, the truth of which is obvious and the truth of which is in no way doubted, are also necessarily and absolutely true. Therefore, the deduction used in mathematics is a solid way of inference that leaves no room for doubt. Because the truth of the premises discussed is clear and distinct. When the deductive way of inference, that is, a kind of syllogism example, is applied to these premises, the conclusion is unequivocally true.
Therefore, Descartes shows the deduction applied in mathematics as a way of deriving precise knowledge. But Descartes’ definition of deduction is somewhat different: he states that “an absolutely necessary inference from facts known with certainty is to make deductions”. The basic question here is: “What are the known facts with certainty?” or “How do we know the truth of obvious premisses?” At this point, the way of thinking or method, which we call intuition, comes into play.
According to Descartes, deduction is the necessary inference from facts known with certainty.
Prepared by: Sociologist Ömer YILDIRIM
Source: Omer YILDIRIM’s Personal Lecture Notes. Atatürk University Sociology Department 1st Year “Introduction to Philosophy” and 2nd, 3rd, 4th Grade “History of Philosophy” Lecture Notes (Ömer YILDIRIM); Open Education Philosophy Textbook