Dependence on Rational Concepts
Source: Al-Mizan by Allamah Tabatabai
Should we rely on rational concepts, in addition to the things perceptible through the senses? It is a subject of great controversy among the western scholars of the later days. All Muslim philosophers as well as most of the western ones of ancient times believed that we can rely on the rational as well as the sensual perceptions. They were rather of the opinion that an academic premises does not look at a tangible and sensual factor as such. But most of the modern scholars, especially the scientists, hold that nothing can be relied upon except what one perceives through the five senses. Their proof is as follows:
Pure rational proofs often go wrong. There is no test or experiment, perceptible through the senses, to verify those rational proofs or their premises.
Sensual perceptions are free from this defect; when we perceive a thing through a sense, we verify it through repeated tests and experiments; this testing continues till we are sure of the characteristics or properties of the object of test.
Therefore, sensual perception is free from doubt, while rational proof is not.
But this argument has many flaws:
First: All the above-mentioned premises are rational; they cannot be perceived by any of the five senses. In other words, these scholars are using rational premises, to prove that rational premises cannot be relied upon! What a paradox! If they succeed in proving their view-point through these premises, their very success would prove them wrong.
Second: Sensual perception is not less prone to error and mistake than rational proof. A cursory glance at the books dealing with the optics and other such subjects is enough to show how many errors are made by sight, hearing and other senses. If rational proof is unreliable because of its possible mistakes, sensual perception also should be discarded for the same reason.
Third: No doubt, there should be a way to distinguish the right perception from the wrong. But it is not the "repeated testing", per se, that creates that distinction in our mind. Rather, it becomes one of the premises of a rational proof which in turn provides that distinction. When we discover a property of an object, and the property remains the same through repeated tests, a rational proof, on the following lines, is offered by our thinking power. If this property were not this thing's own property, it would not be found in it so unfailingly; But it is always found in it without fail; Therefore, it is its own property. It is now obvious that sensual perception too depends on rational premises to finalize its findings.
Fourth: Let us admit that practically every sensual perception is supported by test. But is that test verified by another test? If yes, then the same question will arise about this later one. Obviously, it cannot go on ad infinitum; there must come at the end a test whose verification depends not on a visible test but on the above-mentioned rational proof. It means that one cannot rely on sensual perception without relying on rational concepts.
Fifth: The five senses cannot perceive absolute and major issues; they know only the particular and minor things. Knowledge depends on absolute issues, which cannot be tested in a laboratory nor can they be grasped by the five senses. A professor of anatomy operates upon, or dissects, a number of living or dead human bodies - it does not matter how large or small that number is. He finds that each of the bodies - which he has opened - has a heart, a liver and the like. And after looking at those particular cases, he feels bold enough to teach an absolute proposition that all men have a heart and a liver. The question is: Has he seen inside "all" the human beings? If only that much can be relied upon which is perceived by the five senses, how can any absolute proposition of any branch of science be accepted as true?
The fact is that sensual perception and rational concept both have their place in the field of knowledge; both are complementary to each other. By rationality and understanding, we mean that faculty which is the source of the above examples of absolute principles. Everyone knows that man has such a faculty. How can a faculty created by Allāh (or as they say, by nature) be always in wrong? How can it always fail in the function entrusted to it by the Creator? The Creator never entrusts any work to an agent until He creates a connecting link between them.
So far as mistakes in rational and sensual faculties are concerned, the reader should look for it in related subjects like logic etc.