In regard to the brain there are two errors; but Heaven save my friends only from one of them. For from the other Reimarus can guard them, who has fully proved that the brain is no Æolian harp with trembling strings, nor a camera-obscura with sliding pictures, nor a barrel-organ with pins for every idea, which the spirit turns, in order of itself to play to and from itself its ideas. If now not even the pre-established _harmony_ of the brain and the mind, nor the mutual _accompaniment_ of the two, is conceivable, so is their _identity_ absolutely impossible; and this is precisely the error from which the abovementioned Heaven has to keep my friends. The materialist must first set up all that which Reimarus has overthrown; he must petrify in the brain-pap the millions of picture-cabinets of seventy years, and yet again make them movable like _Eidophysica_,[137] and deal out the shuffled card-images to every second of time; he must see to it that these _animated_ dancing images are forced into rank and file. And then, after all, and only then, does his difficulty properly begin; for now--even if we grant him that the images see themselves, the thoughts think themselves, that every imagination darkly mirrors all others, and even the conscious "I," as a monad, does the universe--now (we say) he must first get him a generalissimo who shall command and array this immeasurable, fluctuating host of ideas, a compositor who shall set up the idea-book from an unknown manuscript, and, when dreams, fevers, passions, have shaken all the letter-cases into _pi_, shall rearrange all the letters alphabetically. This ruling unity and power--without which the _symmetry of the microcosm_ is as inexplicable as that of the _macrocosm_, that of _the ideal world_ as that of the _actual_--is precisely what we call a spirit. To be sure, by this unknown power neither the origin nor the succession of ideas is _mediated_ or explained, but, assuming only the known force of matter, motion, all that is not only incredible, but absolutely impossible; and Leibnitz can more easily explain motion by dark imaginings, than the materialist can imaginings by motions. In the former case motion is only semblance, and exists only in the second contemplating being, but in the latter the representation would be show and would exist in the second--_representing_ substance.