As no man fording a swift stream can dip his foot twice into the same
water, so no man can, with exactness, affirm of anything in the sensible
world that it is. As he utters the words, nay, as he thinks them, the
predicate ceases to be applicable; the present has become the past; the
"is" should be "was." And the more we learn of the nature of things, the
more evident is it that what we call rest is only unperceived activity;
that seeming peace is silent but strenuous battle. In every part, at
every moment, the state of the cosmos is the expression of a transitory
adjustment of contending forces; a scene of strife, in which all the
combatants fall in turn. What is true of each part is true of the whole.
Natural knowledge tends more and more to the conclusion that "all the
choir of heaven and furniture of the earth" are the transitory forms of
parcels of cosmic substance wending along the road of evolution, from
nebulous potentiality, through endless growths of sun and planet and
satellite; through all varieties of matter; through infinite diversities
of life and thought; possibly, through modes of being of which we
neither have a conception, nor are competent to form any, back to
the indefinable latency from which they arose. Thus the most obvious
attribute of the cosmos is its impermanence. It assumes the aspect not
so much of a permanent entity as of a changeful process, in which naught
endures save the flow of energy and the rational order which pervades
it.