The human mind feels restless and dissatisfied under the anxieties of ignorance. It longs for the repose of conviction; and to gain this repose it will often rather precipitate its conclusions than wait for the tardy lights of observation and experiment. There is such a thing, too, as the love of simplicity and system,--a prejudice of the understanding which disposes it to include all the phenomena of nature under a few sweeping generalities,--an indolence which loves to repose on the beauties of a theory rather than encounter the fatiguing detail of its evidences.