usation." When the phenomena are
complex the deductive method must be called in to aid: from the inductively
ascertained laws of the action of single causes this deduces the laws
of their combined action; and, as a final step, the results of such
ratiocination are verified by the proof of their agreement with empirical
facts. To explain a phenomenon means to point out its cause; the
explanation of a law is its reduction to other, more general laws. In all
this, however, we remain within the sphere of phenomena; the essence of
nature always eludes our knowledge.

In the chapter "Of Liberty and Necessity" (book vi. chap, ii.) Mill
emphasizes the position that the necessity to which human actions are
subject must not be conceived, as is commonly done, as irresistible
compulsion, for it denotes nothing more than the uniform order of our
actions and the possibility of predicting them. This does not destroy
the element in the idea of freedom which is legitimate and practically
valuable: we have the power to alter our character; it is formed _by_ us
as well as _for_ us; the desire to mould it is one of the most influential
circumstances in its formation. The principle of morality is the promotion
of the happiness of all sentient beings. Mill differs from Bentham,
however, from whom he derives the principle of utility, in several
important particulars--by his recognition of qualitative as well as of
quantitative differences in pleasures, of the value of the ordinary rules
of morality as intermediate principles, of the social feelings, and of the
disinterested love of virtue. Opponents of the utilitarian theory have
not been slow in availing themselves of the opportunities for attack thus
afforded.[1] A third distinguished representative of the same general
movement is Alexander Bain, the psychologist (born 1818; _The Senses and
the Intellect_, 3d ed., 1868; _The Emotions and the Will_, 3d ed., 1875;
_Mental and Moral Science_, 1868, 3d ed., 1872, part ii., 1872; _Mind and
Body_, 3d ed., 1874).

[Footnote 1: On the relation of Bentham and Mill cf. Hoeffding, p. 68:
Sidgwick's _Outlines_, chap. iv. Sec. 16; and John Grote's _Examination of the
Utilitarian Philosophy_, 1870, chap. i.]

The system projected by Herbert Spencer (born 1820), the major part of
which has already appeared, falls into five parts: _First Principles_,
1862, 7th ed., 1889; _Principles of Biology_, 1864-67, 4th ed., 1888;
_Principles of Psychology_, 1855, 5