Dr. Warren asserts that "the Dynamical theory of matter" is now generally accepted by "Anglo-Saxon _naturalists_." "One can scarcely open a scientific treatise without observing the altered stand-point" (p. 160). We confess that we are disappointed with Dr. Warren's treatment of this simple question of fact. On so fundamental an issue, the Doctor ought to have given the name of at least _one_ "naturalist" who asserts that "the ultimate atoms of matter are as uniformly efficient as minds." Leibnitz, Morrell, Ulrici, Hickok, the authorities quoted by him, are metaphysicians and idealists of the extremest school. At present we shall, therefore, content ourselves with a general denial of this wholesale statement of Dr. Warren; and we shall sustain that denial by a selection from the many authorities we shall hereafter present. "No particle of matter possesses within itself the power of changing its existing state of motion or of rest. Matter has no spontaneous power either of rest or motion, but is equally susceptible to each as it may be acted on by _external_ causes" (Silliman's "Principles of Physics," p. 13). The above proposition is "a truth on which the whole science of mechanical philosophy ultimately depends" (Encyclopædia Britannica, art. "Dynamics," vol. viii. p. 326). "A material substance existing alone in the universe could not produce any effects. There is not, so far as we know, a self-acting material substance in the universe" (M'Cosh, "Divine Government, Physical and Moral," p. 78). "Perhaps the only true indication of matter is _inertia_." "The cause of gravitation is _not resident_ in the particles of matter merely," but also "_in all space_" (Dr. Faraday on "Conservation of Force," in "Correlation and Conservation of Force." (p. 368). He also quotes with approbation the words of Newton, "That gravity should be innate, inherent, and essential to matter, is so great an absurdity, that I believe no man who has in philosophic matters a competent faculty of thinking can ever fall into it" p. 368). "The 'force of gravity' is an improper expression" (p. 340). "Forces are transformable, indestructible, and, _in contradistinction from matter_, imponderable" (p. 346). "The first cause of things is Deity" (Dr. Mayer, in "Correlation and Conservation of Force," p. 341). "Although the word _cause_ may be used in a secondary and subordinate sense, as meaning antecedent forces, yet in an abstract sense it is totally inapplicable; we can not predicate of any physical agent that it is abstractedly the cause of another" (p. 15). "Causation is the _will_," "creation is the act, of God" Grove on "Correlation of Physical Forces," (p. 199). "Between gravity and motion it is impossible to establish the equation required for a rightly-conceived _causal_ relation" ("Correlation and Conservation of Force," p. 253). See also Herschel's "Outlines of Astronomy," p. 234.