# What is a syllogism, syllogisms

June 27, 2021 Off By Felso

William of Ockham, after thus examining propositions made with conjunctions ‘and’, ‘or’, deals with syllogisms made with these propositions.

According to William of Ockham, some syllogisms are demonstrative, some are topical, and some are neither topical nor demonstrative.

A demonstrative reasoning is the initial knowledge of the conclusion from propositions known as necessary and explicit. Topical reasoning starts from probabilistic propositions. Probabilistic propositions are propositions that seem true to everyone or the vast majority or wise people. So. Probabilistic propositions, though true and necessary, are not obtained by reasoning. Propositions that are not clearly known through experimentation, that are not inferred from empirical propositions.

Although probabilistic propositions are necessary, they are neither the principle nor the result of demonstration (William: 1990, 83).

Topical reasoning does not cause us to doubt that we are wrong. It is a belief about which we will not doubt, which we have acquired through topical reasoning (William: 1990, 84).

General Laws of Interest: According to William of Ockham, the validity of a syllogism (reasoning) of any kind depends on certain rules. William of Ockham lists these rules as follows.

1) A direct error never arises: an inference is not valid if the premises are true and the conclusion false. Here, the premise precedes the conclusion, precedes the conclusion. Therefore, the premise is sometimes one proposition, sometimes more than one. While the premise is true in an inference, the conclusion may be false, but in a valid deduction, if all the premises are true, the conclusion is certainly not false.

2) A false proposition may be followed by a true proposition. Sometimes a true or false proposition is followed by a false conclusion: “All men are animals. Stone is man. So stone is an animal.”

3) If a conclusion is valid, then the opposite of the premise is followed by the opposite of the conclusion: “Every man is white. Socrates is not white. So Socrates is not human” is valid and true.

4) The premise that precedes the conclusion becomes the conclusion that precedes the premise. The proposition “All animals run. Therefore all men run” is also expressed as “All men run”, “All animals run”.

5) A valid conclusion must be consistent with the premises and the conclusion. Whatever is consistent with the premise is also consistent with the conclusion.

6) What is inconsistent with the conclusion is also inconsistent with the premises

7) A contingent result does not come from a necessary importance.

8) No possible conclusion follows from an impossible premise.

Ockham William. separated philosophy and theology. According to him, while philosophy is a field dominated by reason, theology is a field dominated by proofs and explanations. William of Ockham stated that philosophy and theology should be separated from each other, and he also said that the Church should reduce its effectiveness in state administration. In this respect, it seems to have laid the foundations of the new, ‘secular’ structuring that would become evident in the Renaissance Period.

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; Hacettepe University Journal of the Faculty of Letters Vol: 18 / Issue: 1 / pp. 165-186