cribed as the inexpugnable
resolve of everything to have its own way.

The equality of cause and effect defines and interprets the
unconditionality of causation. The cause, we have seen, is that group of
conditions which, without any further condition, is followed by a given
event. But how is such a group to be conceived? Unquantified, it admits
only of a general description: quantified, it must mean a group of
conditions equal to the effect in mass and energy, the essence of the
physical world. Apparently, a necessary conception of the human mind:
for if a cause seem greater than its effect, we ask what has become of
the surplus matter and energy; or if an effect seem greater than its
cause, we ask whence the surplus matter and energy has arisen. So
convinced of this truth is every experimenter, that if his results
present any deviation from it, he always assumes that it is he who has
made some mistake or oversight, never that there is indeterminism or
discontinuity in Nature.

The transformation of matter and energy, then, is the essence of
causation: because it is continuous, causation is immediate; and because
in the same circumstances the transformation always follows the same
course, a cause has invariably the same effect. If a fire be lit
morning after morning in the same grate, with coal, wood, and paper of
the same quality and similarly arranged, there will be each day the same
flaming of paper, crackling of wood and glowing of coal, followed in
about the same time by the same reduction of the whole mass partly to
ashes and partly to gases and smoke that have gone up the chimney. The
flaming, crackling and glowing are, physically, modes of energy; and the
change of materials into gas and ashes is a chemical and physical
redistribution: and, if some one be present, he will be aware of all
this; and then, besides the physical changes, there will be sensations
of light, sound and heat; and these again will be always the same in the
same circumstances.

The Cause of any event, then, when exactly ascertainable, has five
marks: it is (quantitatively) _equal_ to the effect, and (qualitatively)
_the immediate, unconditional, invariable antecedent of the effect_.

Sec. 3. This scientific conception of causation has been developed and
rendered definite by the investigations of those physical sciences that
can avail themselves of exact experiments and mathematical calculation;
and it is there, in Chemistry and Physics