THE LAW OF UNIVERSAL CAUSATION.
Phenomena in nature stand to each other in two relations, that of
simultaneity, and that of succession. On a knowledge of the truths
respecting the succession of facts depends our power of predicting and
influencing the future. The object, therefore, must be to find some law
of succession not liable to be defeated or suspended by any change of
circumstances, by being tested by, and deduced from which law, all other
uniformities of succession may be raised to equal certainty. Such a law
is not to be found in the class of laws of number or of space; for
though these are certain and universal, no laws except those of space
and number can be deduced from them by themselves (however important
_elements_ they may be in the ascertainment of uniformities of
succession). But causation is such a law; and of this, moreover, all
cases of succession whatever are examples.
This _Law of Causation_ implies no particular theory as to the ultimate
production of effects by _efficient_ causes, but simply implies the
existence of an invariable order of succession (on our assurance of
which the validity of the canons of inductive logic depends) found by
observation, or, when not yet observed, believed, to obtain between an
invariable antecedent, i.e. the _physical_ cause, and an invariable
consequent, the effect. This sequence is generally between a consequent
and the _sum_ of several antecedents. The cause is really the sum total
of the conditions, positive and negative; the negative being stated as
one condition, the same always, viz. the absence of counteracting causes
(since one cause generally counteracts another by the same law whereby
it produces its own effects, and, therefore, the particular mode in
which it counteracts another may be classed under the positive causes).
But it is usual, even with men of science, to reserve the name _cause_
for an antecedent _event_ which completes the assemblage of conditions,
and begins to exist immediately before the effect (e.g. in the case of
death from a fall, the slipping of the foot, and not the weight of the
body), and to style the permanent facts or _states_, which, though
existing immediately before, have also existed long previously, the
_conditions_. But indeed, popularly, any condition which the hearer is
least likely to be aware of, or which needs to be dwelt upon with
reference to the particular occasion, will be selected as the cause,
even a negative condition (e.g. the sentinel's absence from his post, as
the cause of a surprise), though from a mere negation no consequence can
really proceed. On the other hand, the object which is popularly
regarded as standing in the relation of _patient_, and as being the mere
theatre of the effect, is never styled _cause_, being included in the
phrase describing the effect, viz. as the object, of which the effect is
_a state_. But really these so-called _patients_ are themselves agents,
and their properties are positive conditions of the effect. Thus, the
death of a man who has taken prussic acid is as directly the effect of
the organic properties of the man, i.e. the _patient_, as of the poison,
i.e. the _agent_.
To be a cause, it is not enough that the sequence _has been_ invariable.
Otherwise, night might be called the cause of day; whereas it is not
even a condition of it. Such relations of succession or coexistence, as
the succession of day and night (which Dr. Whewell contrasts as _laws of
phenomena_ with _causes_, though, indeed, the latter also are laws of
phenomena, only more universal ones), result from the coexistence of
real causes. The causes themselves are followed by their effects, not
only invariably, but also _necessarily_, i.e. _unconditionally_, or
subject to none but negative conditions. _This_ is material to the
notion of a cause. But another question is not material, viz. whether
causes _must_ precede, or may, at times, be simultaneous with (they
certainly are never preceded by) their effects. In some, though not in
all cases, the causes do invariably continue _together with_ their
effects, in accordance with the schools' dogma, _Cessante causa, cessat
et effectus_; and the hypothesis that, in such cases, the effects are
produced _afresh_ at each instant by their cause, is only a verbal
explanation. But the question does not affect the theory of causation,
which remains intact, even if (in order to take in cases of simultaneity
of cause and effect) we have to define a cause, as the assemblage of
phenomena, which occurring, some other phenomenon invariably and
unconditionally commences, or has its origin.
There exist certain original natural agents, called permanent causes
(some being objects, e.g. the earth, air, and sun; others, cycles of
events, e.g. the rotation of the earth), which together make up nature.
All other phenomena are immediate or remote effects of these causes.
Consequently, as the state of the universe at one instant is the
consequence of its state at the previous instant, a person (but only if
of more than human powers of calculation, and subject also to the
possibility of the order being changed by a new volition of a supreme
power) might predict the whole future order of the universe, if he knew
the original distribution of all the permanent causes, with the laws of
the succession between each of them and its different mutually
independent effects. But, in fact, the distribution of these permanent
causes, with the reason for the proportions in which they coexist, has
not been reduced to a law; and this is why the sequences or coexistences
among the effects of several of them together cannot rank as laws of
nature, though they are invariable while the causes coexist. For this
same reason (since the proximate causes are traceable ultimately to
permanent causes) there are no original and independent uniformities of
coexistence between effects of different (proximate) causes, though
there may be such between different effects of the same cause.
Some, and particularly Reid, have regarded man's voluntary agency as
the true type of causation and the exclusive source of the idea. The
facts of inanimate nature, they argue, exhibit only antecedence and
sequence, while in volition (and this would distinguish it from physical
causes) we are conscious, prior to experience, of power to produce
effects: volition, therefore, whether of men or of God, must be, they
contend, an efficient cause, and the only one, of all phenomena. But, in
fact, they bring no positive evidence to show that we could have known,
apart from experience, that the effect, e.g. the motion of the limbs,
would follow from the volition, or that a volition is more than a
physical cause. In lieu of positive evidence, they appeal to the
supposed conceivableness of the direct action of will on matter, and
inconceivableness of the direct action of matter on matter. But there is
no inherent law, to this effect, of the conceptive faculty: it is only
because our voluntary acts are, from the first, the most direct and
familiar to us of all cases of causation, that men, as is seen from the
structure of languages (e.g. their active and passive voices, and
impersonations of inanimate objects), get the _habit_ of borrowing them
to explain other phenomena by a sort of original Fetichism. Even Reid
allows that there is a tendency to assume volition where it does not
exist, and that the belief in it has its sphere gradually limited, in
proportion as fixed laws of succession among external objects are
discovered.
This proneness to require the appearance of some necessary and natural
connection between the cause and its effect, i.e. some reason _per se_
why the one should produce the other, has infected most theories of
causation. But the selection of the particular agency which is to make
the connection between the physical antecedent and its consequent seem
_conceivable_, has perpetually varied, since it depends on a person's
special habits of thought. Thus, the Greeks, Thales, Anaximenes, and
Pythagoras, thought respectively that water, air, or number is such an
agency explaining the production of physical effects. Many moderns,
again, have been unable to _conceive_ the production of effects by
volition itself, without some intervening agency to connect it with
them. This medium, Leibnitz thought, was some _per se_ efficient
physical antecedent; while the Cartesians imagined for the purpose the
theory of Occasional Causes, that is, supposed that God, not _qua_ mind,
or _qua_ volition, but _qua_ omnipotent, intervenes to connect the
volition and the motion: so far is the mind from being forced to think
the action of mind on matter more _natural_ than that of matter on
matter. Those who believe volition to be an efficient cause are guilty
of exactly the same error as the Greeks, or Leibnitz or Descartes; that
is, of requiring an _explanation_ of physical sequences by something
[Greek: aneu hou to aition ouk an pot' eie aition]. But they are guilty
of another error also, in inferring that volition, even if it is an
_efficient_ cause of so peculiar a phenomenon as nervous action, must
therefore be the efficient cause of all other phenomena, though having
scarcely a single circumstance in common with them.