Aristotelian logic, also known as analytics, it is not a science, but a propaedeutics (introduction) to the sciences. She studies the elements (categories) that make up speeches, their rules and functions.
These elements or categories are in themselves undefinable. They are considered supreme genres, that is, universals. Thus, when one wants to define a concept, it is necessary to look for similarities, that is, a genre closer to the category used, as well as the specific difference. Indefinable are also the individuals that can only be perceived because of their particularity. What is definable, therefore, is what lies between the universality of categories and the particularity of individuals.
Propositions or declarative judgments about reality carry semantic values of real or false. Aristotle distinguished three judicial possibilities:
- Apodictic Judgments: they are composed of universal and necessary propositions, whether they are positive or negative. Ex.:
"All men are rational" or "No square has three sides."
- Hypothetical Judges: they are made up of possible or conditioned universal or particular propositions. Ex.:
“If education is good, men will be virtuous”.
- Disjunctive Judges: they are those that contain universal or particular propositions, whether negative or positive, but as an alternative that depends on the facts. Ex.:
“Or Tomorrow will rain, or it will not rain”.
From this distinction, Aristotle was able to systematize the syllogisms in two modes: the Dialectical Syllogism it's the Scientific Syllogism. You Dialectical Syllogisms they are judgments made up of hypothetical and/or disjunctive judgments, as they refer only to opinions, what is plausible or probable, not being, therefore, the object of science, but of persuasion. They are used in rhetoric because they aim to convince and not demonstrate a truth. already the Scientific Syllogisms they are made up of apodictic judgments, since science aims to demonstrate beyond the truth, the universality and necessity of its arguments. For this, there are four rules, as seen below:
1. The premises must be true and not just possible or probable;
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2. The premises must be indemonstrable, for the proof is the argument itself, and if we tried to prove the propositions, there would be a regress to infinity;
3. The premises must be clearer or more intelligible than the conclusion drawn from them;
4. The premises must be the cause of the conclusion. According to Aristotle, knowing means knowing through causes.
This is how we understand that the premises of a Scientific Syllogism are unprovable, evident and causal, establishing the three ways of doing science:
THE. From Axioms, which are self-evident propositions, such as the three logical principles (identity, non-contradiction, and excluded third) or statements such as “The whole is greater than the parts”.
B. You Postulates, which are presuppositions that all science uses to start the studies of its objects, such as flat space, movement and rest, in modern physics.
Ç. Second Definitions, that is, what the thing to be studied is how it is, why it is, and under what conditions it is (what, how, why, if?). It is through the middle term (which fulfills the four requirements) that the concept is reached, because the definition offers the concept through the categories and the necessary inclusion of the individual in the species and in the genre. The concept offers the essence of the object.
Science is, therefore, knowledge that goes from the highest, most universal genus to the most singular species, and the passage between these takes place through a deductive chain (deduction). To define is to find the specific difference between beings of the same gender.
By João Francisco P. Cabral
Brazil School Collaborator
Graduated in Philosophy from the Federal University of Uberlândia - UFU
Master's student in Philosophy at the State University of Campinas - UNICAMP