Logical Deduction Quotes

Mathematical reasoning may be regarded.

Deduction, which takes us from the general proposition to facts again-teaches us, if I may so say, to anticipate from the ticket what is inside the bundle.

Twice two makes four seems to me simply a piece of insolence. Twice two makes four is a pert coxcomb who stands with arms akimbo barring your path and spitting. I admit that twice two makes four is an excellent thing, but if we are to give everything its due, twice two makes five is sometimes a very charming thing too.

If you claim to have a theory that deduces unexpected consequences from nontrivial principles, let's see it.

Mathematics, in its widest significance, is the development of all types of formal, necessary, deductive reasoning.

There is a fundamental difference between religion, which is based on authority, [and] science, which is based on observation and reason. Science will win because it works.

Intellect begins with the observation of nature, proceeds to memorize and classify the facts thus observed, and by logical deduction builds up that edifice of knowledge properly called science… But admittedly we also know by feeling, and we can combine the two faculties, and present knowledge in the guise of art.

Facts - behind them lies the whole fabric of deductive truth.

Reasoning is the pastime of my whole household, and all this reasoning has driven out Reason.

Algebras deal not with laws of number, but with such laws of the human thinking machinery as have been discovered in the course of investigations on numbers. Plane geometry deals with such laws of thought as were discovered by men intent on finding out how to measure surface; and solid geometry with such additional laws of thought as were discovered when men began to extend geometry into three dimensions.

Induction for deduction, with a view to construction.

Logic, n. The art of thinking and reasoning in strict accordance with the limitations and incapacities of the human misunderstanding. The basic of logic is the syllogism, consisting of a major and a minor premise and a conclusion - thus: Major Premise: Sixty men can do a piece of work sixty times as quickly as one man. Minor Premise: One man can dig a post-hole in sixty seconds; Therefore- Conclusion: Sixty men can dig a post-hole in one second. This may be called syllogism arithmetical, in which, by combining logic and mathematics, we obtain a double certainty and are twice blessed.

Mathematics is concerned only with the enumeration and comparison of relations.

Mathematics is entirely free in its development, and its concepts are only linked by the necessity of being consistent, and are co-ordinated with concepts introduced previously by means of precise definitions.

There are two modes of acquiring knowledge, namely by reasoning and experience. Reasoning draws a conclusion and makes us grant the conclusion, but does not make the conclusion certain, nor does it remove doubt so that the mind may rest on the intuition of truth, unless the mind discovers it by the path of experience.

Observation, reason, and experiment make up what we call the scientific method.

Now this foreknowledge cannot be elicited from spirits; it cannot be obtained inductively from experience, nor by any deductive calculation.

The grand aim of all science is to cover the greatest number of empirical facts by logical deduction from the smallest number of hypotheses or axioms.

In this complex world, the scientific method, and the consequences of the scientific method are central to everything the human race is doing and to wherever we are going.

In some ways we live in a world where things appear to be very logical, very rational, and mechanical aspects of our world are rather scientific and rather straightforward.

Remember that [scientific thought] is the guide of action; that the truth which it arrives at is not that which we can ideally contemplate without error, but that which we may act upon without fear; and you cannot fail to see that scientific thought is not an accompaniment or condition of human progress, but human progress itself.

Ah! my dear Watson, there we come into those realms of conjecture, where the most logical mind may be at fault. Sherlock Holmes speaking with Dr. Watson.

Once you've ruled out the impossible then whatever is left, however improbable, must be the truth. The problem lay in working out what was impossible, of course. That was the trick, all right. There was also the curious incident of the orangutan in the night-time.

[P]rescientific people... could never guess the nature of physical reality beyond the tiny sphere attainable by unaided common sense. Nothing else ever worked, no exercise from myth, revelation, art, trance, or any other conceivable means; and notwithstanding the emotional satisfaction it gives, mysticism, the strongest prescientific probe in the unknown, has yielded zero.

When I was a kid, I loved Sherlock Holmes. I'm not interested in crimes. I'm interested in the mind of the detective and his process, which to me is a lot like the artist.