ions against
hastily confounding the laws of development of planets, development of the
organic kingdom, and development {150} of the individual organisms.
Recently, Wigand, in the second volume of his work already frequently
mentioned, attempts, with an extreme energy which does too little justice
to the representation and investigation of the still unsolved problems, to
formulate the limits of the knowable.

A contrary extreme, and of its kind a still more one-sided corrective of
this too great stability, we have in those investigators who, by reason of
the great progress which has been made in the realm of the theoretical
knowledge of nature, allow themselves to be drawn on to the hope of still
explaining all states and processes in the world--the spiritual and the
ethic processes as well as the physical--from the pure mechanism of atoms;
and who see in that which thus far has been mechanically explained, the
only and the infallible way of explaining all that is still obscure. They
call this view the _mechanical view of the world_; and, as "monism," put it
in opposition to the "vitalistic, teleological, and dualistic view of the
world." In order to obtain a correct view of this standpoint, we quote from
Haeckel's "Natural History of Creation", Vol. I, page 23, the following
passage: "By the theory of descent we are for the first time enabled to
conceive of the unity of nature in such a manner that a mechanico-causal
explanation of even the most intricate organic phenomena, for example, the
origin and structure of the organs of sense, is no more difficult (in a
general way) than is the mechanical explanation of any physical process;
as, for example, earthquakes, the courses of the wind, or the currents of
the ocean. We thus arrive at the extremely important conviction that _all
natural bodies_ which are known to us are _equally {151} animated_, that
the distinction which has been made between animate and inanimate bodies
does _not_ exist. When a stone is thrown into the air, and falls to earth
according to definite laws, or when in a solution of salt a crystal is
formed, the phenomenon is neither more nor less a mechanical manifestation
of life than the growth and flowering of plants, than the propagation of
animals or the activity of their senses, than the perception or the
formation of thought in man." Here crystallization, organic life,
sensation, and formation of thought, are expressly put in one line of
mechanism