If fourteen-year old students received a solid introduction to Aristotle’s logic, it would change their lives; it could help them stay away from trouble, prevent bad decisions and acquire self-confidence.
Aristotle (384-322 BC) did not teach ready-made solutions, but methods for solving problems. The purpose of logic is to see beyond the obvious, assess the facts, and draw conclusions that are in line with all available evidence.
Aristotle’s teachings on logic and reasoning are presented in his book “Categories” and the twin treatises “Prior Analytics” and “Posterior Analytics.” They outline a method that is easy to grasp, but hard to apply consistently in every area of life.
“Categories” is just an introductory work to logic. Its goal is to define terminology to describe the characteristics of objects, plants, animals, and human beings. For instance, Aristotle talks about categories relating to space, time, cause and effect, etc.
Deduction versus induction in Aristotle’s logic
“Prior Analytics” and “Posterior Analytics” are devoted to a single subject, namely, how to draw correct conclusions from statements and facts. Aristotle uses examples consisting of two statements or facts; he call those examples “premises” and then explains how to assess them and draw an accurate conclusion.
In Aristotelian terminology, a syllogism typically consists of two premises that lead to a conclusion by means of deductive reasoning. From the premises A and B, we draw an inescapable conclusion that is verifiable true.
In the example “all sentences contain words” and “a story is made of sentences,” we can draw the conclusion that “a story is made of words.” The premises share the term “sentences.” In the conclusion, we are connecting “story” and “words” through the middle term “sentences.”
Does Aristotelian logic sound simple? Indeed, it seems easy but we make mistakes all the time. Very often, people will not see the facts that are right before their eyes; their blindness can be self-inflicted or caused by ignorance, tiredness, or fear.
Apathy is another reason why we fail to employ Aristotelian logic. People will clearly perceive the premises or facts but fail to draw any conclusions; they will overlook the obvious due to laziness, apathy, or discouragement.
“Posterior Analytics” is devoted to inductive reasoning. It is the method for drawing general principles from specific facts, statements, or experiments. The key to accurate inductive logic is to check that the premises and conclusion are connected by a solid, verifiable link, not by chance or coincidence.
Thomas Aquinas’ distortion of Aristotle’s logic
In order to apply Aristotelian logic consistently in our lives, I recommend the following guidelines.
First, if you don’t have clear premises, it’s too early to draw a conclusion. Don’t fall for the temptation of inventing facts or statements, just to arrive at a conclusion. If you do so, you will be building on sand. You’ll go in the wrong direction and waste your time and energies.
Thomas Aquinas (1225-1274) committed the error of trying to draw conclusions from unclear premises; he wrote copiously about his “conclusions,” but he should have rather called them “speculations.”
Aquinas was too eager to demonstrate that Aristotelian logic is compatible with Christian religion, and that God’s existence can be inferred through deductive and inductive syllogisms.
He came up with a dozen examples and demonstrations that rival in absurdity. Why? Because, in every case, Aquinas had invented facts or statements.
Aristotle had emphasized that the goal of logic is to draw conclusions from true facts, not to invent facts that fit a certain narrative. Aquinas did exactly the contrary. He started with a ready-made conclusion (that God has created the universe out of nothing from scratch) and then struggled to look for facts.
Arbitrary statements versus Aristotle’s logic
Second, if you dislike a conclusion, check the premises and their logical connection. If they all prove accurate, ask yourself why you are reluctant to accept them. If your convictions aren’t aligned with reality, you should check where they are wrong.
Unfortunately, Aquinas committed this error repeatedly. You can find it on almost every page of his “Summa Theologiae,” published in 1269. Aristotle logic led to conclusions explaining physical phenomena on mechanical grounds. Aquinas disliked Aristotle’s conclusions because they did not fit with his views that all events are driven by the divine providence.
Was it worth it for Aquinas to write hundreds of pages with the goal of undermining conclusions that seem perfectly solid? Should he not rather have checked if his convictions about the divine providence were undermining his logic?
The consistent use of Aristotle’s logic
Third, use logic consistently in all areas of life, and don’t let people intimidate you into accepting arbitrary statements. Stay away from proposals that seem too good to be true. Stay away from proposals that are not supported by facts and logic.
Aristotle called for using logic on every occasion, especially when it comes to making important decisions. I find surprising that some individuals prefer to rely on emotions or intuition in important matters. I don’t think they will get good results, but I wish them luck.
Aquinas vastly preferred to rely on emotions and intuition. I appreciate his clear exposition of Aristotelian logic, but deeply regret that he circumscribed its field of application.
For Aquinas, every crucial issue should be decided by faith and by faith alone. Logic plays only an accessory role. He saw in divine revelation a primary source of knowledge that should not be logically questioned. In doing so, Aquinas was reducing Aristotelian logic to a second-rate tool from which little should be expected.
The three principles that I have presented can help you draw the most benefit from Aristotelian logic. If you want to practise good logic consistently in everyday life, I recommend you my book “The philosophy of builders.”
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