Verb
To follow up step by step by patient inquiry or observation; to trace or track mentally; to search into; to inquire and examine into with care and accuracy; to find out by careful inquisition; as, to investigate the causes of natural phenomena.
To pursue a course of investigation and study; to make investigation.
Source: Webster's dictionaryNothing has such power to broaden the mind as the ability to investigate systematically and truly all that comes under thy observation in life. Marcus Aurelius
Psychoanalysis pretends to investigate the Unconscious. The Unconscious by definition is what you are not conscious of. But the Analysts already know what's in it - they should, because they put it all in beforehand. Saul Bellow
The conscience of the world is so guilty that it always assumes that people who investigate heresies must be heretics; just as if a doctor who studies leprosy must be a leper. Indeed, it is only recently that science has been allowed to study anything without reproach. Aleister Crowley
Medicine to produce health must examine disease; and music, to create harmony must investigate discord. Plutarch
Bankruptcy is a sacred state, a condition beyond conditions, as theologians might say, and attempts to investigate it are necessarily obscene, like spiritualism. One knows only that he has passed into it and lives beyond us, in a condition not ours. John Updike
I have ever been prone to seek adventure and to investigate and experiment where wiser men would have left well enough alone. Edgar Rice Burroughs