Mill's Autobiography, Part 2
“The Socratic method, of which the Platonic dialogues are the chief example, is unsurpassed as a discipline for correcting the errors, and clearing up the confusions incident to the intellectus sibi permissus [mind left to itself], the understanding which has made up all its bundles of associations under the guidance of popular phraseology. The close, searching elenchus [method of eliciting truth by questioning] by which the man of vague generalities is constrained either to express his meaning to himself in definite terms, or to confess that he does not know what he is talking about; the perpetual testing of all general statements by particular instances; the siege in form which is laid to the meaning of large abstract terms, by fixing upon some still larger class-name which includes that and more, and dividing down to the thing sought — marking out its limits and definition by a series of accurately drawn distinctions between it and each of the cognate objects which are successively parted off from it — all this, as an education for precise thinking, is inestimable, and all this, even at that age, took such hold of me that it became part of my own mind.”