A promise of science

Logic is a field that is concerned with the structure, shape or correctness of the arguments. Since Aristotle has been one of the most important tools that humanity uses to draw conclusions. Allied to mathematics, logic becomes the most ferocious of judges. In fact, if it is desirable to check the consistency of a given argument during a discussion, we evaluate their compliance with the rules of logic.

We cannot even say we have an argument, if our proposal does not comply with a given structure that authorizes their validity. Aristotle created the syllogism, a kind of logic form to argumentation. Then present a classic example of Aristotelian syllogism:

All men are mortal
Socrates is a man
therefore, Socrates is mortal

This syllogism makes the explanation easier. Logical arguments must be in the form proposed. Thus, starting from the assumptions related follows a conclusion obligatorily derived from premisses. One things that many scientists, and even some philosophers, proud is to follow the commandments of logic to make inferences. However, the logic can be a criterion of validity for itself?

It is well known that logic is not concerned with the truth of the premisses. Evaluate the truth value is a function of epistemology, not of logic. In fact, we may have a valid argument (legitimate) starting from false premisses since the shape/structure of the argument is correct. When we developed hypotheses or scientific predictions these actions must meet criteria that make them valid. That is why we use the logic correction. This ensures that our actions are on track and makes the general public to deposit some credibility in arguments. If you want, is something similar to what happens when you go to the store to buy a new refrigerator because his old consumed a lot of energy. You choose between brands that suit you best and take home the one with the Procel Energy Efficiency Seal (INMETRO).

That question could be inconvenient. Inmetro ensures the efficiency of the product, but who ensures Inmetro efficiency during the process? In our analogy the product (your refrigerator) is equivalent to scientific theories and Inmetro is equivalent to logic. The situation is uncomfortable, I confess. However, that’s a real problem with which we must deal in science and also in philosophy. There is no way to test the logic, you must assume that it is infallible and can offer the best rules for reasoning. In the early 1900, Vienna was the capital of logic. There, a group of influential philosophers created what became known as the Vienna Circle. Wrote many papers and appreciated, above all, the use of logic as a criterion of correctness of the intellect. Were called logical positivists, since they believed to be the logic infallible. In mathematics something similar happens with systems based on axioms. The axioms are, by definition, self-evident truths, that eliminate the need for proof. A good example are the axioms of Euclid:

1. Two things equal to a third are equal to each other.
2. The whole is greater than the part.

How quickly realizes, no one would doubt these simple propositions. Are sufficiently intuitive and seem very clear. Exactly why they are called axioms. Well, but let us return to logic. My analogy with the Inmetro seal has a purpose. Show that, although you might question who evaluates Inmetro, this does not eliminate the fact that Inmetro is not just printing the warranty seal based on psychological tests. Experimental tests were carried out in your fridge and as a son who enters into university, at the end of exhaustive testing your refrigerator was approved and received the degree of energy efficiency. The same applies to scientific theories. The first test is undoubtedly the logical, but the next step is the experimental test.

Karl Popper believed in logic fallibilism. Claimed to be our knowledge contingent. He was not a skeptic because not believed to be impossible to access the truth. Nor was a relativist, because he did not believe that all forms of knowledge are valid. He was a realist, and sought to separate logic, mathematics, and metaphysical systems on the one hand and science on the other. Saw in nature the need to use logic and mathematics only as tools of science without absolutize the conclusions derived therefrom.

Science has increased our understanding about the nature and much that was unknown 100 years ago is now commonplace. We can assume that the answers we lack today, will be the basis for new questions in a few years. After all, the promise of science to mankind is that there will always new questions. Absolutize logic can kill the promise of science.


Karl Popper. Conhecimento objetivo: uma abordagem evolucionária. Belo Horizonte: Itatiaia, 1975.
Peter Medawar. Os limites da ciência. São Paulo: UNESP, 2008.

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This work by Alison Felipe Alencar Chaves is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.



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