Quotes about logic, Ludwig von Mises

Quotes about logic from the book “Human Action”, by Ludwig von Mises.

“Thinking and acting are the specific human features of man. They are peculiar to all human beings. They are, beyond membership in the zoological species homo sapiens, the characteristic mark of man as man. It is not the scope of praxeology to investigate the relation of thinking and acting. For praxeology it is enough to establish the fact that there is only one logic that is intelligible to the human mind, and that there is only one mode of action which is human and comprehensible to the human mind. Whether there are or can be somewhere other beings--superhuman or subhuman--who think and act in a different way, is beyond the reach of the human mind. We must restrict our endeavors to the study of human action.

This human action which is inextricably linked with human thought is conditioned by logical necessity. It is impossible for the human mind to conceive logical relations at variance with the logical structure of our mind. It is impossible for the human mind to conceive a mode of action whose categories would differ from the categories which determine our own actions.

There are for man only two principles available for a mental grasp of reality, namely, those of teleology and causality. What cannot be brought under either of these categories is absolutely hidden to the human mind. An event not open to an interpretation by one of these two principles is for man inconceivable and mysterious. Change can be conceived as the outcome either of the operation of mechanistic causality or of purposeful behavior; for the human mind there is no third way available [9]. It is true, as has already been mentioned, that teleology can be viewed as a variety of causality. But the establishment of this fact does not annul the essential differences between the two categories.”

http://www.mises.org/humanaction/chap1sec6.asp

“But the problem of the a priori is of a different character. It does not deal with the problem of how consciousness and reason have emerged. It refers to the essential and necessary character of the logical structure of the human mind.
The fundamental logical relations are not subject to proof or disproof. Every attempt to prove them must presuppose their validity. It is impossible to explain them to a being who would not possess them on his own account. Efforts to define them according to the rules of definition must fail. They are primary propositions antecedent to any nominal or real definition. They are ultimate unanalyzable categories. The human mind is utterly incapable of imagining logical categories at variance with them. No matter how they may appear to superhuman beings, they are for man inescapable and absolutely necessary. They are the indispensable prerequisite of perception, apperception, and experience.”

“Everybody in his daily behavior again and again bears witness to the immutability and universality of the categories of thought and action. He who addresses fellow men, who wants to inform and convince them, who asks questions and answers other people's questions, can proceed in this way only because he can appeal to something common to all men--namely, the logical structure of human reason. The idea that A could at the same time be non-A or that to prefer A to B could at the same time be to prefer B to A is simply inconceivable and absurd to a human mind. We are not in the position to comprehend any kind of prelogical or metalogical thinking. We cannot think of a world without causality and teleogy.”

“It is a general fallacy to believe that the writings of Lucien Levy-Bruhl give support to the doctrine that the logical structure of mind of primitive man was and is categorially different from that of civilized man. On the contrary, what Levy-Bruhl, on the basis of a careful scrutiny of the entire ethnological material available, reports about the mental functions of primitive man proves clearly that the fundamental logical relations and the categories of thought and action play in the intellectual activities of savages the same role they play in our own life. The content of primitive man's thoughts differs from the content of our thoughts, but the formal and logical structure is common to both.”

http://www.mises.org/humanaction/chap2sec2.asp#p33

“We may refer to what has been said in the preceding chapters about the fundamental issues of the logical structure of mind and the categorial principles of thought and action. Some additional observations will suffice to give the finishing stroke to racial polylogism and to any other brand of polylogism.
The categories of human thought and action are neither arbitrary products of the human mind nor conventions. They are not outside of the universe and of the course of cosmic events. They are biological facts and have a definite function in life and reality. They are instruments in man's struggle for existence and in his endeavors to adjust himself as much as possible to the real state of the universe and to remove uneasiness as much as it is in his power to do so. They are [p. 86] therefore appropriate to the structure of the external world and reflect properties of the world and of reality. They work, and are in this sense true and valid.
It is consequently incorrect to assert that aprioristic insight and pure reasoning do not convey any information about reality and the structure of the universe. The fundamental logical relations and the categories of thought and action are the ultimate source of all human knowledge. They are adequate to the structure of reality, they reveal this structure to the human mind and, in this sense, they are for man basic ontological facts.[14] We do not know what a superhuman intellect may think and comprehend. For man every cognition is conditioned by the logical structure of his mind and implied in this structure. It is precisely the satisfactory results of the empirical sciences and their practical application that evidence this truth. Within the orbit in which human action is able to attain ends aimed at there is no room left for agnosticism.

If there had been races which had developed a different logical structure of the mind, they would have failed in the use of reason as an aid in the struggle for existence. The only means for survival that could have protected them against extermination would have been their instinctive reactions. Natural selection would have eliminated those specimens of such races that tried to employ reasoning for the direction of their behavior. Those individuals alone would have survived that relied upon instincts only. This means that only those would have had a chance to survive that did not rise above the mental level of animals.

The scholars of the West have amassed an enormous amount of material concerning the high civilizations of China and India and the primitive civilizations of the Asiatic, American, Australian, and African aborigines. It is safe to say that all that is worth knowing about the ideas of these races is known. But never has any supporter of polylogism tried to use these data for a description of the allegedly different logic of these peoples and civilizations.”

http://www.mises.org/humanaction/chap3sec4.asp#p86

Björn Lundahl
Göteborg, Sweden