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Why Does Conflating Reason and Logic

Lead to Confusion & Endless Useless Controversy?

A PHILOSOPHICAL CONSIDERATION/PROPOSITION: Contrary to much popular and academic opinion, logic is not synonymous with reason or even the foundation of rational thinking. Logic is only a small part of reason because most rational inferences are not, strictly speaking, logical inferences.

Let us take an illustration. You look out of the window, and observe that you can see three houses. You turn back into the room and say “three houses are visible from the window.” The kind of sceptic that I have in mind would say “you mean three houses were visible.” You would reply “but they can’t have vanished in this little moment.” You might look again and say “yes, there they are still.” The sceptic would retort: “I grant that when you looked again they were there again, but what makes you think they had been there in the interval?” You would only be able to say “because I see them whenever I look.” The sceptic would say “then you ought to infer that they are caused by your looking.” You will never succeed in getting any evidence against this view, because you can’t find out what the houses look like [i.e. if the houses are still there] when no one is looking at them.

Bertrand Russell

[A COMPLICATION: Instead of being used in the strict sense of syllogistic reasoning (i.e. a series of deductive inferences), the word ‘logic’ is often used in a wider sense to mean: the course of action or line of reasoning suggested or made necessary by some thing or situation. In such cases language is distorted if one tries to substitute the word ‘reason’ for ‘logic.’ Here are some examples of the informal use of the words ‘logic’ and ‘logically’:]

Life is seldom as unendurable as, to judge by the facts, it logically ought to be.

Brooks Atkinson

Conflict or competition carried to an extreme will tend to produce sameness on all sides. A single inexorable logic will finally reduce everything to the same terms.

David Cayley

In prose each sentence follows out of its predecessor, either logically or rhetorically.

Love is always unreasonable. There is no logic to love.

The aim of the new criticism was to penetrate the inner logic of texts rather than their meaning. The extreme example of this is what is now called deconstructionism with its claim that texts refer to nothing outside themselves.

George Woodcock, himself a partisan of animal welfare, called animal rights activists “self-righteous and egotistical to an extreme.” The inner logic of these crusaders goes like this. (1) The social change I am advocating will have beneficial results. (2) Therefore it is a righteous cause. (3) Therefore I am a righteous person. (4) Therefore anyone who opposes me is a bad person.

Philip Marchand


Logical deductions are infallibly valid, but not infallibly true.

If nothing is self-evident, nothing can be proved. There are some premises that can’t be reached as conclusions.

C. S. Lewis

To prove that anything is true you need some truth to start with.

As nothing can be proved but by supposing something intuitively known, and evident without proof, so nothing can be defined but by the use of words too plain to admit a definition.

Samuel Johnson

No argument can establish the truth of its premises, since if it tried to do so it would be circular; and therefore no argument can establish the truth of its conclusions.

Bryan Magee

Logical principles are known to us, and cannot be themselves proved by experience, since all proof presupposes them.

Bertrand Russell

Simple logical relationships are, in fact, insights. It is only because they seem so self-evident and because the contrary defies our imagination that they are not recognized as insights.

Not everything can be justified on the basis of reasoned argument. Some things have to be justified on the basis of instinct or intuition, which, in turn, depend on faith or that closely related thing, common sense.

Without faith—or something very like it—logic can’t get any traction.

You can only find truth with logic if you have already found truth without it.

G. K. Chesterton

Logic is always an ‘if. . . then. . .’ process which proceeds from the known to the unknown. But if nothing is known at the beginning of the process, then nothing can ever be known. You can’t use logic to generate knowledge from a state of total ignorance.

As logic improves, less and less can be proved . . . Deduction has turned out to be much less powerful than was formerly supposed.

Bertrand Russell


Every error is due to extraneous factors (such as emotion and education); reason itself does not err.

Kurt Gödel

Logic can convince, but only emotion can motivate.

Jonathan Alter

True philosophy is the marriage of poetry and logic.

John Stuart Mill

Reason is merely an instrument which, correctly employed, helps people draw inferences from given premises without inconsistency.

A. C. Grayling

What is true conscience, that which comes from reason or that which one feels intuitively?

Pierre Elliott Trudeau (in a letter to a girl friend)

[The following statement from a feature on the near-death experience of neurosurgeon Eben Alexander is from an Australian news and current affairs program called Sunday Night.]

The man you are about to meet is a man of science, a brain surgeon centred in logic, which is why his story of having died and gone to heaven is being seriously reported as proof the afterlife does exist.

In 1870 the first Vatican Council declared: ‘If anyone should say that no miracles can be performed, . . . or that they can never be known with certainty, or that by them the divine origin of the Christian religion cannot be rightly proved—let him be anathema.’*

* a formal curse by a pope or a council of the Church, excommunicating a person or denouncing a doctrine

[The following argument from Cicero has a logical form. But does his conclusion really follow logically from his premises, especially in the absence of a definition for ‘miracle’?]

Miracles were denied even in classical antiquity. Thus, Cicero asserted that ‘nothing happens without a cause, and nothing happens unless it can happen. When that which can happen does in fact happen, it cannot be considered a miracle. Hence, there are no miracles.’

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