The investigation of nature requires no habits or qualities of mind, but such as may always be acquired by industry and mental activity. Because at one time the mind may be so given up to a state of feeling, that the succession of its ideas is determined by the present enjoyment or suffering which pervades it, this is no reason but that in the calm retirement of study, when under no peculiar excitement either of the outward or of the inward sense, it may form any combinations, or pursue any trains of ideas, which are most conducive to the purposes of philosophic inquiry; and may, while in that state, form deliberate convictions, from which no excitement will afterwards make it swerve. Might we not go even further than this? We shall not pause to ask whether it be not a misunderstanding of the nature of passionate feeling to imagine that it is inconsistent with calmness; whether they who so deem of it, do not mistake passion in the militant or antagonistic state, for the type of passion universally; do not confound passion struggling towards an outward object, with passion brooding over itself. But without entering into this deeper investigation; that capacity of strong feeling, which is supposed necessarily to disturb the judgement, is also the material out of which all _motives_ are made; the motives, consequently, which lead human beings to the pursuit of truth. The greater the individual’s capability of happiness and of misery, the stronger interest has that individual in arriving at truth; and when once that interest is felt, an impassioned nature is sure to pursue this, as to pursue any other object, with greater ardour; for energy of character is commonly the offspring of strong feeling. If, therefore, the most impassioned natures do not ripen into the most powerful intellects, it is always from defect of culture, or something wrong in the circumstances by which the being has originally or successively been surrounded. Undoubtedly strong feelings require a strong intellect to carry them, as more sail requires more ballast: and when, from neglect, or bad education, that strength is wanting, no wonder if the grandest and swiftest vessels make the most utter wreck.