ideas out of themselves, like the spiders; but the true philosopher must be
like the bee, which by its own power transforms and digests the gathered
material.

As the mind, like a dull and uneven mirror, by its own nature distorts the
rays of objects, it must first of all be cleaned and polished, that is, it
must be freed from all prejudices and false notions, which, deep-rooted by
habit, prevent the formation of a true picture of the world. It must root
out its prejudices, or, where this is impossible, at least understand them.
Doubt is the first step on the way to truth. Of these Phantoms or Idols to
be discarded, Bacon distinguishes four classes: Idols of the Theater, of
the Market Place, of the Den, and of the Tribe. The most dangerous are
the _idola theatri_, which consist in the tendency to put more trust in
authority and tradition than in independent reflection, to adopt current
ideas simply because they find general acceptance. Bacon's injunction
concerning these is not to be deceived by stage-plays (_i.e._, by the
teachings of earlier thinkers which represent things other than they are);
instead of believing others, observe for thyself! The _idola fori_, which
arise from the use of language in public intercourse, depend upon the
confusion of words, which are mere symbols with a conventional value and
which are based on the carelessly constructed concepts of the vulgar, with
things themselves. Here Bacon warns us to keep close to things. The _idola
specus_ are individual prepossessions which interfere with the apprehension
of the true state of affairs, such as the excessive tendency of thought
toward the resemblances or the differences of things, or the investigator's
habit of transferring ideas current in his own department to subjects of a
different kind. Such individual weaknesses are numberless, yet they may in
part be corrected by comparison with the perceptions of others. The _idola
tribus_, finally, are grounded in the nature of the human species. To this
class belong, among others, illusions of the senses, which may in part be