Verb

(en verb)

To detect with the senses, especially with the eyes.

* {{quote-book

, year=1875 , author=Jules Verne , title=The Survivors of the Chancellor , chapter=1 citation , passage=Meanwhile the brig had altered her tack, and was moving slowly to the east. Three hours later and the keenest eye could not have discerned her top-sails above the horizon.}}

To perceive, recognize, or comprehend with the mind; to descry.

* {{quote-book

, year=1842 , author=Charles Dickens , title=American Notes for General Circulation citation , passage=If they discern' any evidences of wrong-going in any direction that I have indicated, they will acknowledge that I had reason in what I wrote. If they ' discern no such thing, they will consider me altogether mistaken.}}

To distinguish something as being different from something else; to differentiate.

* {{quote-book

, year=1651 , author=Thomas Hobbes , title=Leviathan citation , passage=The severity of judgement, they say, makes men censorious and unapt to pardon the errors and infirmities of other men: and on the other side, celerity of fancy makes the thoughts less steady than is necessary to discern exactly between right and wrong.}}

He was too young to discern right from wrong.

To perceive differences.

Verb

(en verb)

To find out definitely; to discover or establish.

* {{quote-book, year=1905, author=

, title= , chapter=1 citation , passage=“There the cause of death was soon ascertained ?; the victim of this daring outrage had been stabbed to death from ear to ear with a long, sharp instrument, in shape like an antique stiletto, which […] was subsequently found under the cushions of the hansom. […]”}}

As soon as we ascertain what the situation is, we can plan how to proceed.