George Boole Quotes

That axiom of Metaphysicians which is termed the principle of contradiction and which affirms that it is impossible for anything to possess a quality, and in the same time not to possess it, is a consequence of the fundamental law of thought, whose expression is x²=x.

To deduce the laws of the symbols of Logic from a consideration of those operations of the mind which are implied in the strict use of language as an instrument of reasoning.

That logic, as a science, is susceptible of very wide applications is admitted; but it is equally certain that its ultimate forms and processes are mathematical.

It is not of the essence of mathematics to be conversant with the ideas of number and quantity.

There is not only a close analogy between the operations of the mind in general reasoning and its operations in the particular science of Algebra, but there is to a considerable extent an exact agreement in the laws by which the two classes of operations are conducted.

The general laws of Nature are not, for the most part, immediate objects of perception. They are either inductive inferences from a large body of facts, the common truth in which they express, or, in their origin at least, physical hypotheses of a causal nature serving to explain phenomena with undeviating precision, and to enable us to predict new combinations of them. They are in all cases, and in the strictest sense of the term, probable conclusions, approaching, indeed, ever and ever nearer to certainty, as they receive more and more of the confirmation of experience. But of the character of probability, in the strict and proper sense of that term, they are never wholly divested. On the other hand, the knowledge of the laws of the mind does not require as its basis any extensive collection of observations. The general truth is seen in the particular instance, and it is not confirmed by the repetition of instances.

[Boole's apparent goal was to] unfold the secret laws and relations of those high faculties of thought by which all beyond the merely perceptive knowledge of the world and of ourselves is attained or matured, is a object which does not stand in need of commendation to a rational mind.

The design of the following treatise is to investigate the fundamental laws of those operations of the mind by which reasoning is performed; to give expression to them in the symbolical language of a Calculus, and upon this foundation to establish the science of Logic and construct its method ; to make that method itself the basis of a general method for the application of the mathematical doctrine of Probabilities ; and, finally, to collect from the various elements of truth brought to view in the course of these inquiries some probable intimations concerning the nature and constitution of the human mind.

The following work is not a republication of a former treatise by the Author, entitled, "The Mathematical Analysis of Logic." Its earlier portion is indeed devoted to the same object, and it begins by establishing the same system of fundamental laws, but its methods are more general, and its range of applications far wider. It exhibits the results, matured by some years of study and reflection, of a principle of investigation relating to the intellectual operations, the previous exposition of which was written within a few weeks after its idea had been conceived.

Perhaps it is in the thought that there does exist an Intelligence and Will superior to our own,—that the evolution of the destinies of our species is not solely the product either of human waywardness or of human wisdom; perhaps, I say, it is in this thought, that the conception of humanity attains its truest dignity. When, therefore, I use this term, I would be understood to mean by it the human race, viewed in that mutual connexion and dependence which has been established, as I firmly believe, for the accomplishment of a purpose of the Divine mind... One eminent instance of that connexion and dependence to which I have referred is to be seen in the progression of the arts and sciences. Each generation as it passes away bequeaths to its successor not only its material works in stone and marble, in brass and iron, but also the truths which it has won, and the ideas which it has learned to conceive; its art, literature, science, and, to some extent, its spirit and morality. This perpetual transmission of the light of knowledge and civilisation has been compared to those torch-races of antiquity in which a lighted brand was transmitted from one runner to another until it reached the final goal. Thus, it has been said, do generations succeed each other, borrowing and conveying light, receiving the principles of knowledge, testing their truth, enlarging their application, adding to their number, and then transmitting them forward to coming generations

I am fully assured, that no general method for the solution of questions in the theory of probabilities can be established which does not explicitly recognize, not only the special numerical bases of the science, but also those universal laws of thought which are the basis of all reasoning, and which, whatever they may be as to their essence, are at least mathematical as to their form.

The scepticism of the ancient world left no department of human belief unassailed. It took its chief stand upon the conflicting nature of the impressions of the senses, but threw the dark shade of uncertainty over the most settled convictions of the mind; over men's belief in an external world, over their consciousness of their own existence. But this form of doubt was not destined to endure. Science, in removing the contradictions of sense, and establishing the consistent uniformity of natural law, took away the main pillars of its support. The spirit, however, and the mental habits of which it was the product, still survive; but not among the votaries of science. For I cannot but regard it as the same spirit which, with whatever profession of zeal, and for whatever ends of supposed piety or obedience, strives to subvert the natural evidences of morals, - the existence of a Supreme Intelligent Cause. There is a scepticism which repudiates all belief; there is also a scepticism which seeks to escape from itself by a total abnegation of the understanding, and which, in the pride of its new-found security, would recklessly destroy every internal ground of human trust and hope... Now to this, as to a former development of the sceptical spirit, Science stands in implied but real antagonism.

I am now about to set seriously to work upon preparing for the press an account of my theory of Logic and Probabilities which in its present state I look upon as the most valuable if not the only valuable contribution that I have made or am likely to make to Science and the thing by which I would desire if at all to be remembered hereafter.

A successful attempt to express logical propositions by symbols, the laws of whose combinations should be founded upon the laws of the mental processes which they represent, would, so far, be a step towards a philosophical language.

That to the existing forms of Analysis a quantitative interpretation is assigned, is the result of the circumstances by which those forms were determined, and is not to be construed into a universal condition of Analysis. It is upon the foundation of this general principle, that I purpose to establish the Calculus of Logic, and that I claim for it a place among the acknowledged forms of Mathematical Analysis, regardless that in its object and in its instruments it must at present stand alone.