Usefulness of the Famous Division of Science into Obvious and Theoretical in Logic of Affirmations

Most Muslim logicians divide the acquired science into the obvious and theoretical with the criterion of thought. The purpose of this study is to investigate the usefulness of this division in the logic of affirmations. The main benefit of this division, with the aim of finding out the truth in the science of logic, is to show the need to the science of logic in moving from the obvious propositions to theoretical ones; but in relation to the obvious immediate perceptions, because of their being certain, there is no need for this science. Analyzing the thought and various obvious propositions, we can conclude that "obviousness" cannot be a factor in the certainty of affirmation, because some of other people's immediate perceptions are false in our view. The certainty of each immediate perception is related to factors other than their being obvious. Although all our immediate perceptions are certain for us, we do not pay attention to the other people's acknowledgment factor in evaluating their thoughts. We examine their arguments in terms of the formal and material rules of reasoning. The thought is not discussed anywhere in the science of logic except in the division of science into the obvious and the theoretical, and this is a proof of the uselessness of this division. An alternative division, based on the existence or absence of argument, divide science into sub-structural and super-structural. The validity of the argument in super-structural affirmations is checked in the science of logic. The logic of affirmations is the science of error detection in reasoning, not thought.