Noun

A natural or inherent impulse or behaviour.

Many animals fear fire by instinct .

* Shakespeare

By a divine instinct , men's minds mistrust / Ensuing dangers.

* {{quote-book

, year=1921 , title= , author=Bertrand Russell , passage=In spite of these qualifications, the broad distinction between instinct and habit is undeniable. To take extreme cases, every animal at birth can take food by instinct, before it has had opportunity to learn; on the other hand, no one can ride a bicycle by instinct, though, after learning, the necessary movements become just as automatic as if they were instinctive.}}

An intuitive reaction not based on rational conscious thought.

an instinct''' for order; to be modest by '''instinct

Debbie's instinct was to distrust John.

Noun

(en noun)

A cause:

# That which causes something: an efficient cause, a proximate cause.

#* 1996 , (w), : Evolution and the Meanings of Life , page 198:

There is a reason why so many should be symmetrical: The selective advantage in a symmetrical complex is enjoyed by all the subunits

# A motive for an action or a determination.

#* 1806 , Anonymous, Select Notes to Book XXI, in, (Alexander Pope), translator, The (Odyssey) of (Homer) , volume 6 (London, F.J. du Roveray), page 37:

This is the reason why he proposes to offer a libation, to atone for the abuse of the day by their diversions.

#* 1881 , (Henry James), (The Portrait of a Lady) , chapter 10:

Ralph Touchett, for reasons best known to himself, had seen fit to say that Gilbert Osmond was not a good fellow

# An excuse: a thought or a consideration offered in support of a determination or an opinion; that which is offered or accepted as an explanation.

#* 1966 , (Graham Greene), ((Penguin Classics) edition, ISBN 0140184945), page 14:

I have forgotten the reason' he gave for not travelling by air. I felt sure that it was not the correct ' reason , and that he suffered from a heart trouble which he kept to himself.

(label) Rational]] thinking (or the capacity for it; the cognitive [[faculty, faculties, collectively, of conception, judgment, deduction and intuition.

* 1970 , (Hannah Arendt), On Violence (ISBN 0156695006), page 62:

And the specific distinction between man and beast is now, strictly speaking, no longer reason (the lumen naturale of the human animal) but science

*{{quote-magazine, date=2014-06-21, volume=411, issue=8892, magazine=(The Economist)

, title= Magician’s brain , passage=The [Isaac] Newton that emerges from the [unpublished] manuscripts is far from the popular image of a rational practitioner of cold and pure reason . The architect of modern science was himself not very modern. He was obsessed with alchemy.}}

(label) Something reasonable, in accordance with thought; justice.

* (rfdate) (Edmund Spenser):

I was promised, on a time, To have reason for my rhyme.

Ratio; proportion.

(Barrow)