Thomas Carlyle on Agile

But indeed Conviction, were it never so excellent, is worthless till it convert itself into Conduct. Nay properly Conviction is not possible till then; inasmuch as all Speculation is by nature endless, formless, a vortex amid vortices: only by a felt indubitable certainty of Experience does it find any centre to revolve round, and so fashion itself into a system. ... Do the Duty which lies nearest thee, which though knowest to be a Duty! Thy second Duty will already have become clearer.

-- Thomas Carlyle in Sartor Resartus.