rocally
related to all, and all, collectively, form one magnificent whole--since
all stars and worlds mutually act and react upon each other, to cause day
and night, summer and winter, sun and rain, blossom and fruit; since every
genus, species, and individual throughout nature is second or sixteenth
cousin to every other; and since man is the epitome of universal nature,
the embodiment of all her functions, the focus of all her light, and
representative of all her perfections--of course to understand _him_
thoroughly is to know _all_ things. Nor can nature be studied
advantageously without him for a text-book, nor he without her.

Moreover, since man is composed of mind _and_ body, both reciprocally and
most intimately related to each other--since his mentality is manifested
only by bodily organs, and the latter depends wholly upon the former, of
course his mind can be studied only through its ORGANIC relations. If it
were manifested independently of his physiology, it might be studied
separately, but since all his organic conditions modify his mentality, the
two must be studied TOGETHER. Heretofore humanity has been studied by
piece-meal. Anatomists have investigated only his organic structure, and
there stopped; and mental philosophers have studied him metaphysically,
wholly regardless of all his physiological relations; while theologians
have theorized upon his moral faculties alone; and hence their utter
barrenness, from Aristotle down. As if one should study nothing but the
trunk of a tree, another only its roots, a third its leaves, or fruit,
without compounding their researches, of what value is such piecemeal
study? If the physical man constituted one whole being, and the mental
another, their separate study might be useful; but since all we know of
mind, and can do with it, is manifested and done wholly by means of
physical instruments--especially since every possible condition and change
of the physiology correspondingly affects the mentality--of course their
MUTUAL relations, and the laws of their RECIPROCAL action, must be
investigated _collectively_. Besides, every mental philosopher has
deduced his system from his own closet cogitations, and hence their
babel-like confusion. But within the last half century, a new star, or
rather sun, has arisen upon the horizon of mind--a sun which puts the
finger of SCIENTIFIC CERTAINTY upon every mental faculty, and discloses
those _physiological_ conditions which affec