94. TRADITIONAL CONCEPT OF CAUSE.—The modes of real being which we have
been so far examining—substance, quality, quantity, relation—are modes of
reality considered as _static_. But it was pointed out in an early chapter
(ch. ii.) that the universe of our experience is subject to change, that
it is ever _becoming_, that it is the scene of a continuous world-process
which is apparently regulated by more or less stable principles or laws,
these laws and processes constituting the _universal order_ which it is
the duty of the philosopher to study and explain. We must now return to
this _kinetic_ and _dynamic_ aspect of reality, and investigate the
principles of change in things by a study of _Causes_.
As with the names of the other ultimate categories, so too here, the
general sense of the term “cause” (_causa_, αἴτιον) is familiar to all,
while analysis reveals a great variety of modalities of this common
signification. We understand by a cause _anything which has a positive
influence of any sort on the being or happening of something else_. In
philosophy this is the meaning which has been attached traditionally to
the term since the days of Aristotle; though in its present-day scientific
use the term has almost lost this meaning, mainly through the influence of
modern phenomenism.(434) The traditional notion of cause is usually
expounded by comparing it with certain kindred notions: _principle_,
_condition_, _occasion_, _reason_.
A _principle_ is _that from which anything proceeds in any way
whatsoever_.(435) Any sort of intrinsic connexion between two objects of
thought is sufficient to constitute the one a “principle” of the other;
but a mere extrinsic or time sequence is not sufficient. A _logical_
principle is some _truth_ from which further truths are or may be derived.
A _real_ principle is some _reality_ from which the _being_ or _happening_
of something originates and proceeds.(436) If this procession involves a
real and positive influence of the principle on that which proceeds from
it, such a real principle is a cause. But there may be a real and
intrinsic connexion without any such influence. For instance, in the
substantial changes which occur in physical nature the generation of the
new substantial formative principle necessarily presupposes the
_privation_ of the one which antecedently “informed” the material
principle; but this “_privatio formae_” has no positive influence on the
generation of the new “form”; it is, however, the necessary and natural
antecedent to the generation of the latter; hence although this “_privatio
formae_” is a real principle of substantial change (the process or
_fieri_) it is not a _cause_ of the latter. The notion of principle, even
of real principle, is therefore wider than the notion of cause.(437)
A _condition_, in the proper sense of a necessary condition or _conditio
sine qua non_, is something which must be realized or fulfilled before the
event or effect in question can happen or be produced. On the side of the
latter there is real dependence, but from the side of the former there is
no real and positive influence on the happening of the event. The
influence of the condition is negative; or, if positive, it is only
indirect, consisting in the removal of some obstacle—“_removens
probibens_”—to the positive influence of the cause. In this precisely a
condition differs from a cause: windows, for instance, are a condition for
the lighting of a room in the daylight, but the sun is the cause. The
distinction is clear and intelligible, nor may it be ignored in a
philosophical analysis of causality. At the same time it is easy to
understand that where, as in the inductive sciences, there is question of
discovering _all_ the antecedents, positive and negative, of any given
kind of phenomenon, in order to bring to light and formulate the law or
laws according to which such phenomenon occurs, the distinction between
cause and condition is of minor importance.(438)
An _occasion_ is _any circumstance or combination of circumstances
favourable to the action of a free cause_. For instance, a forced sale is
an occasion for buying cheaply; night is an occasion of theft; bad
companionship is an occasion of sin. An occasion has no intrinsic
connexion with the effect as in the case of a principle, nor is it
necessary for the production of the effect as in the case of a condition.
It is spoken of only in connexion with the action of a free cause; and it
differs from a cause in having no positive and direct influence on the
production of the effect. It has, however, a real though indirect
influence on the production of the effect by soliciting and aiding the
determination of the free efficient cause to act. In so far as it does
exert such an influence it may be regarded as a partial efficient cause,
not a physical but a moral cause, of the effect.
To ask for the _reason_ of any event or phenomenon, or of the nature or
existence of any reality, is to demand an _explanation_ of the latter; it
is to seek what _accounts_ for the latter, what makes this _intelligible_
to our minds. Whatever is a cause is therefore also a reason, but the
latter notion is wider than the former. Whatever explains a _truth_ is a
_logical_ reason of the latter. But since all truths are concerned with
realities they must have ultimately _real_ reasons, _i.e._ explanatory
principles inherent in the realities themselves. The knowledge of these
real or ontological principles of things is the logical reason of our
understanding of the things themselves. But the ontological principles,
which are the real reasons of the things, are wider in extent than the
causes of these things, for they include principles that are not causes.
Furthermore, the grades of reality which we discover in things by the
activity of abstract thought, and whereby we compare, classify and define
those things, we apprehend as explanatory principles of the latter; and
these principles, though really in the things, and therefore real
“reasons,” are not “causes”.
Thus, life is a real reason, though not a cause, of sensibility in the
animal organism; the soul’s independence of matter in its mode of
existence is a real reason, though not a cause, of its spiritual
activities. Hence, between a reason and that which it accounts for there
may be only a logical distinction, while between a cause and that which it
causes there must be a real distinction (38).
To understand all the intrinsic principles which constitute the _essence_
of anything is to know the _sufficient reason_ of its _reality_. To
understand all the extrinsic principles which account for its actual
_existence_ is to know the sufficient reason of its _existence_; and to
understand this latter adequately is to realize that the thing depends
ultimately for its actual existence on a Reality or Being which
necessarily exists by virtue of its own essence.
What has been called the _Principle of Sufficient Reason_ asserts,
when applied to reality, that every existing reality must have a
sufficient reason for existing and for being what it is.(439)
Unlike the _Principle of Causality_ which is an axiomatic or
self-evident truth, this principle is rather a necessary postulate
of all knowledge, an assumption that _reality is intelligible_. It
does not mean that all reality, or even any single finite reality,
is adequately intelligible to our finite minds. In the words of
Bossuet, we do not know everything about anything: “nous ne savons
le tout de rien”.
In regard to contingent _essences_, if these be composite we can
find a sufficient reason why they are such in their constitutive
principles; but in regard to simple essences, or to the simple
constitutive principles of composite essences, we can find no
sufficient reason why they are such in anything even logically
distinct from themselves: they are what they are because they are
what they are, and to demand why they are what they are, is, as
Aristotle remarked, to ask an idle question. At the same time,
when we have convinced ourselves that their actual existence
involves the existence of a Supreme, Self-Existent, Intelligent
Being, we can see that the essence of this Being is the ultimate
ground of the intrinsic possibility of all finite essences (20).
In regard to contingent _existences_ the Principle of Sufficient
Reason is coincident with the Principle of Causality, inasmuch as
the sufficient reason of the actual existence of any contingent
thing consists in the extrinsic real principles which are its
causes. The existence of contingent things involves the existence
of a Necessary Being. We may say that the sufficient reason for
the existence of the Necessary Being is the Divine Essence Itself;
but this is merely denying that there is outside this Being any
sufficient reason, _i.e._ any cause of the latter’s existence; it
is the recognition that the Principle of Causality is inapplicable
to the Necessary Being. The Principle of Sufficient Reason, in
this application of it, is logically posterior to the Principle of
Causality.(440)
95. CLASSIFICATION OF CAUSES: ARISTOTLE’S FOURFOLD DIVISION.—In modern
times many scientists and philosophers have thought it possible to explain
the order and course of nature, the whole cosmic process and the entire
universe of our experience, by an appeal to the operation of _efficient
causes_. Espousing a mechanical, as opposed to a teleological, conception
of the universe, they have denied or ignored all influence of _purpose_,
and eschewed all study of _final causes_. Furthermore, misconceiving or
neglecting the category of substance, and the doctrine of substantial
change, they find no place in their speculations for any consideration of
_formal_ and _material_ causes. Yet without final, formal and material
causes, so fully analysed by Aristotle(441) and the scholastics, no
satisfactory explanation of the world of our experience can possibly be
found. Let us therefore commence by outlining the traditional fourfold
division of causes.
We have seen already that change involves composition or compositeness in
the thing that is subject to change. Hence two _intrinsic_ principles
contribute to the constitution of such a thing, the one a passive,
determinable principle, its _material cause_, the other an active,
determining principle, its _formal cause_. Some changes in material things
are superficial, not reaching to the substance itself of the thing; these
are _accidental_, involving the union of some _accidental_ “form” with the
concrete pre-existing substance as material (_materia_ “_secunda_”).
Others are more profound, changes of the substance itself; these are
_substantial_, involving the union of a new _substantial_ “form” with the
primal material principal (_materia_ “_prima_”) of the substance
undergoing the change. But whether the change be substantial or accidental
we can always distinguish in the resulting composite thing two intrinsic
constitutive principles, its _formal cause_ and its _material cause_. The
agencies in nature which, by their activity, bring about change, are
_efficient causes_. Finally, since it is an undeniable fact that there is
_order_ in the universe, that its processes give evidence of _regularity_,
of operation according to _law_, that the cosmos reveals a _harmonious
co-ordination of manifold_ agencies and a _subordination of means to
ends_, it follows that there must be working in and through all nature a
directive principle, a principle of plan or design, a principle according
to which those manifold agencies work together in fulfilment of a purpose,
_for the attainment of ends_. Hence the reality of a fourth class of
causes, _final causes_.
The separate influence of each of those four kinds of cause can be clearly
illustrated by reference to the production of any work of art. When, for
instance, a sculptor chisels a statue from a block of marble, the latter
is the material cause (_materia secunda_) of the statue, the form which he
induces on it by his labour is the formal cause (_forma accidentalis_),
the sculptor himself as agent is the efficient cause, and the motive from
which he works—money fame, esthetic pleasure, etc.—is the final cause.
The formal and material causes are _intrinsic_ to the effect; they
constitute the effect _in facto esse_, the distinction of each from the
latter being an inadequate real distinction. It is not so usual nowadays
to call these intrinsic constitutive principles of things _causes_ of the
latter; but they verify the general definition of cause. The other two
causes, the efficient and the final, are _extrinsic_ to the effect, and
really and adequately distinct from it,(442) extrinsic principles of its
production, its _fieri_.
This classification of causes is adequate;(443) it answers all the
questions that can be asked in explanation of the production of any
effect: _a quo?_ _ex quo?_ _per quid?_ _propter quid?_ Nor is there any
sort of cause which cannot be brought under some one or other of those
four heads. What is called an “exemplar cause,” _causa exemplaris_, _i.e._
the ideal or model or plan in the mind of an intelligent agent, according
to which he aims and strives to execute his work, may be regarded as an
extrinsic formal cause; or again, in so far as it aids and equips the
agent for his task, an efficient cause; or, again, in so far as it
represents a good to be realized, a final cause.(444)
The objects of our knowledge are in a true sense causes of our knowledge:
any such object may be regarded as an efficient cause, both physical and
moral, of this knowledge, in so far as by its action on our minds it
determines the activity of our cognitive faculties; or, again, as a final
cause, inasmuch as it is the end and aim of the knowledge.
The essence of the soul is, as we have seen (69), not exactly an efficient
cause of the faculties which are its properties; but it is their final
cause, inasmuch as their _raison d’être_ is to perfect it; and their
subjective or material cause, inasmuch as it is the seat and support of
these faculties.
The fourfold division is analogical, not univocal: though the matter, the
form, the agent, and the end or purpose, all contribute positively to the
production of the effect, it is clear that the character of the causal
influence is widely different in each case.
Again, its members do not demand distinct subjects: all four classes of
cause may be verified in the same subject. For instance, the human soul is
a formal cause in regard to the composite human individual, a material
cause in regard to its habits, an efficient cause in regard to its acts,
and a final cause in regard to its faculties.
Furthermore, the fourfold division is not an immediate division, for it
follows the division of cause in general into _intrinsic_ and _extrinsic_
causes. Finally, it is a division of the causes which we find to be
operative _in_ the universe. But the philosophical study of the universe
will lead us gradually to the conviction that itself and all the causes in
it are themselves _contingent_, themselves caused by and dependent on, a
Cause _outside_ or extrinsic to the universe, a _First_, _Uncaused_,
_Uncreated_, _Self-Existent_, _Necessary Cause_ (_Causa Prima_,
_Increata_), at once the _efficient_ and _final_ cause of all things. In
contrast with this _Uncreated_, _First Cause_, all the other causes we
have now to investigate are called _created_ or _second_ causes (_causae
secundae_, _creatae_).
A cause may be either _total_, _adequate_, or _partial_, _inadequate_,
according as the effect is due to its influence solely, or to its
influence in conjunction with, or dependence on, the influence of some
other cause or causes _of the same order_. A created cause, therefore, is
a total cause if the effect is due to its influence independently of other
created causes; though of course all created causes are dependent, both as
to their existence and as to their causality, on the influence of the
First Cause. Without the activity of created efficient and final causes
the First Cause can accomplish directly whatever these can
accomplish—except their very causality itself, which cannot be actualized
without them, but for which He can supply _eminenter_. Similarly, while it
is incompatible with His Infinite Perfection that He discharge the
function of material or formal cause of finite composite things, He can
immediately create these latter by the simultaneous production (_ex
nihilo_) and union of their material and formal principles.
A cause is said to be _in actu secundo_ when it is actually exercising its
causal influence. Antecedently to such exercise, at least _prioritate
naturae_, it is said to be _in actu primo_: when it has the expedite power
to discharge its function as cause it is _in actu primo proximo_, while if
its power is in any way incomplete, hampered or unready, it is _in actu
primo remoto_.
Many other divisions of cause, subordinate to the Aristotelian division,
will be explained in connexion with the members of this latter.
96. MATERIAL AND FORMAL CAUSES.—These are properly subject-matter for
_Cosmology_. We will therefore very briefly supplement what has been said
already concerning them in connexion with the doctrine of _Change_ (ch.
ii.). By a material cause we mean _that out of which anything is made_:
_id ex quo aliquid fit_. Matter is correlative with form: from the union
of these there results a composite reality endowed with either essential
or accidental unity—with the former if the material principle be
absolutely indeterminate and the correlative form substantial, with the
latter if the material principle be some actually existing individual
reality and the form some supervening accident. Properly speaking only
corporeal substances have material causes,(445) but the term “material
cause” is used in an extended sense to signify any potential, passive,
receptive subject of formative or actuating principles: thus the soul is
the subjective or material cause of its faculties and habits; essence of
existence; _genus of differentia_, etc.
In what does the positive causal influence of a material cause consist?
How does it contribute positively to the actualization of the composite
reality of which it is the material cause? It _receives_ and _unites with_
the form which is educed from its potentiality by the action of efficient
causes, and thus contributes to the generation of the concrete, composite
individual reality.(446)
It is by reason of the causality of the _formal cause_ that we speak of a
thing being _formally_ such or such. As correlative of material cause it
finds its proper application in reference to the constitution of corporeal
things. The formative principle, called _forma substantialis_, which
actuates, determines, specifies the material principle, and by union with
the latter constitutes an individual corporeal substance of a definite
kind, is the (substantial) formal cause of this composite substance.(447)
The material principle of corporeal things is of itself indifferent to any
species of body; it is the form that removes this indefiniteness and
determines the matter, by its union with the latter, to constitute a
definite type of corporeal substance.(448) The existence of different
species of living organisms and different types of inorganic matter in the
universe implies in the constitution of these things a common material
principle, _materia prima_, and a multiplicity of differentiating,
specifying, formative principles, _formae substantiales_. That the
distinction between these two principles in the constitution of any
individual corporeal substance, whether living or inorganic, is not merely
a virtual distinction between metaphysical (generic and specific) grades
of being in the individual, but a real distinction between separable
entities, is a scholastic thesis established in the Special Metaphysics of
the organic and inorganic domains of the universe.(449)
Since the _form_ is a perfecting, actuating principle, the term is often
used synonymously with _actus_, _actuality_. And since besides the
essential perfection which a being has by virtue of its substantial form
it may have accidental perfections by reason of supervening accidental
forms, these, too, are formal causes.
In what does the causal influence of the formal cause consist? In
communicating itself intrinsically to the material principle or passive
subject from whose potentiality it is evoked by the action of efficient
causes; in actuating that potentiality by intrinsic union therewith, and
thus determining the individual subject to be actually or formally an
individual of such or such a kind.
The material and formal causes are _intrinsic_ principles of the
constitution of things. We next pass to an analysis of the two _extrinsic_
causes, and firstly of the efficient cause and its causality.
97. EFFICIENT CAUSE; TRADITIONAL CONCEPT EXPLAINED.—By efficient cause we
understand that _by which_ anything takes place, happens, occurs: _id a
quo aliquid fit_. The world of our external and internal experience is the
scene of incessant _changes_: men and things not only are, but are
constantly _becoming_. Now every such change is originated by some active
principle, and this we call the efficient cause of the change. Aristotle
called it τὸ κινητικόν or ἡ ἀρχὴ κινητική, the _kinetic_ or _moving_
principle; or again, ἀρχὴ κινησέως ἢ μεταβολῆς ἐν ἑτέρω, _principium motus
vel mutationis in alio_, “the principle of motion or change in some other
thing”. The result achieved by this change, the actualized potentiality,
is called the _effect_; the causality itself of the efficient cause is
called _action_ (ποίησις), _motion_, _change_—and, from the point of view
of the effect, _passio_ (παθήσις). The perfection or endowment whereby an
efficient cause acts, _i.e._ its efficiency (ἐνέργεια), is called _active
power_ (_potentia seu virtus activa_); it is also called _force_ or
_potential energy_ in reference to inanimate agents, _faculty_ in
reference to animate agents, especially men and animals. This active power
of an efficient cause or agent is to be carefully distinguished from the
_passive potentiality_ acted upon and undergoing change. The former
connotes a perfection, the latter an imperfection: _unumquodque agit
inquantum est in actu, patitur vero inquantum, est in potentia_. The scope
of the active power of a cause is the measure of its actuality, of its
perfection in the scale of reality; while the extent of the passive
potentiality of _patiens_ is a measure of its relative imperfection. The
actuation of the former is _actio_, that of the latter _passio_. The point
of ontological connexion of the two _potentiae_ is the _change_ (_motus_,
κίνησις), this being at once the formal perfecting of the passive
potentiality in the _patiens_ or effect, and the immediate term of the
efficiency or active power of the _agens_ or cause. _Actio_ and _passio_,
therefore, are not expressions of one and the same concept; they express
two distinct concepts of one and the same reality, _viz._ the change:
_actio et passio sunt idem numero motus_. This change takes place
_formally_ in the subject upon which the efficient cause acts, for it is
an actuation of the potentiality of the former under the influence of the
latter: ἡ κίνησις ἐν τῷ κινητῷ; ἐντελέχεια γὰρ ἐστι τόυτου. Considered in
the potentiality of this subject—“τὸ τοῦδέ ἐν τῷδε: _hujus in hococ_”—it
is called _passio_. Considered as a term of the active power of the
cause—“τοῦδε ὑπο τοῦδε: _hujus per hoc_”—it is called _actio_.
The fact that _actio_ and _passio_ are really and objectively one and the
same _motus_ does not militate against their being regarded as two
separate supreme categories, for they are objects of distinct
concepts,(450) and this is sufficient to constitute them distinct
categories (60).
Doubts are sometimes raised, as St. Thomas remarks,(451) about the
assertion that the action of an agent is not formally in the latter but in
the _patiens_: _actio fit in passo_. It is clear, however, he continues,
that the action is formally in the _patiens_ for it is the actuation not
of any potentiality of the agent, but of the passive potentiality of the
_patiens_: it is in the latter that the _motus_ or change, which is both
_actio_ and _passio_, takes place, dependently of course on the influence
of the agent, or efficient cause of the change. The active power of an
efficient cause is an index of the latter’s actuality; the exercise of
this power (_i.e._ _action_) does not formally perfect the agent, for it
is not an actuation of any passive potentiality of the latter; it formally
perfects the _patiens_. Only _immanent_ action perfects the agent, and
then not as agent but as _patiens_ or receiver of the actuality effected
by the action (_cf._ 103 _infra_).
We may, then, define efficient cause as _the extrinsic principle of the
change or production of anything by means of action_: _principium
extrinsicum a quo fluit motus vel productio rei mediante actione_.
It is a “first” principle as compared with material and formal causes for
its influence is obviously prior in nature to theirs; also as compared
with the other extrinsic cause, the final cause, _in ordine executionis_,
not, however, _in ordine intentionis_. The “end,” not as realized but as
realizable, not in execution but in intention, discharges its function and
exerts its influence as “final _cause_” and in this order the final cause,
as will appear later, is _the first of all causes_: _finis est ultimus in
executione sed primus in intentione_.
“Change or production,” in the definition, is to be understood not in the
strict sense in which it presupposes an existing subject or material, but
in the wide sense in which it includes any production of new reality, even
creation or production _ex nihilo_.
“Action,” too, is to be understood in the wide sense in which it includes
the action of the First Cause, which action is really identical with the
essence of the latter. We conceive creation after the analogy of the
efficient action of created or “second” causes: we have no _proper_
concept of the infinite perfection of the Divine activity. In all created
efficient causes not only is the action itself, but also the efficiency,
force, power, faculty, which is its _proximate_ principle, really distinct
from the nature or essence of the agent; the former is a substance, the
latter an accident.
Finally, the action of a created efficient cause is either transitive
(_transiens_) or immanent (_immanens_) according as the change wrought by
the action takes place in something else (as when _the sun_ heats or
lights _the earth_) or in the cause itself (as when a man reasons or
wills). In the former case the action perfects not the agent but the other
thing, the _patiens_; in the latter case it perfects the agent itself,
_agens_ and _patiens_ being here the same identical concrete
individual.(452)
98. SOME SCHOLIA ON CAUSATION. THE PRINCIPLE OF CAUSALITY.—Before
enumerating the principal kinds of efficient cause, and analysing the
nature of efficient causality, we may set down here certain self-evident
axioms and aphorisms concerning causation in general. (_a_) The most
important of these is the _Principle of Causality_, which has been
enunciated in a variety of ways: _Whatever happens has a cause_; _Whatever
begins to be has a cause_; _Whatever is contingent has a cause_; _Nothing
occurs without a cause_. Not everything that begins to be has necessarily
a _material_ cause, or a _formal_ cause, really distinct from itself. For
instance, simple spiritual beings, like the human soul, have no material
cause, nor any formal cause or constitutive principle distinct from their
essence. Similarly, the whole universe, having been created _ex nihilo_,
had no pre-existing material cause. All the material beings, however,
which are produced, generated, brought into actual existence in the course
of the incessant changes which characterize the physical universe, have
both material and formal causes. But the Principle of Causality refers
mainly to extrinsic causes. It is commonly understood only of efficient
causes; and only in regard to these is it self-evident. We shall see that
as a matter of fact nothing happens without a _final_ cause: that
intelligent purpose pervades reality through and through. This, however,
is a conclusion, not a principle. What is really a self-evident,
axiomatic, necessary principle is that _whatever happens has an_ EFFICIENT
_cause_. Only the Necessary, Self-Existing, Eternal Being, has the
sufficient reason of His actual existence in Himself, in His own essence.
That any being which is contingent could exist _independently of some
other actual being_ as the cause of this existence; that it could have
come into existence or begun to exist _from absolute nothingness, or be
produced or brought into actual existence without any actual being to
produce it_; or that, once existing and subject to change, it could
undergo change and have its potentialities actualized _without any actual
being to cause such change_ (10)—all this is positively unthinkable and
absolutely repugnant to our intelligence; all this our reason peremptorily
declares to be intrinsically impossible. Nor is there question of a mere
psychological inconceivability, such as might be due to a long-continued
custom of associating the idea of a “beginning” with the idea of a “cause”
of this beginning—as phenomenists generally contend.(453) There is
question of an impossibility which our reason categorically dictates to be
a real, ontological impossibility. The Principle of Causality is therefore
a necessary, _a priori_, self-evident principle.
(_b_) _Every effect must have an adequate efficient cause_, _i.e._ a cause
sufficiently perfect, sufficiently high on the scale of being, to have the
active power to produce the effect in question; otherwise the effect would
be partially uncaused, which is impossible.
(_c_) _An effect cannot as such be actually more perfect than its adequate
(created) cause_. The reason is that the effect as such is really
dependent for its actuality on its adequate created cause. It derives its
actuality from the latter. Now it is inconceivable that an agent could be
the active, productive principle of a greater perfection, a higher grade
of actuality, than itself possesses. Whatever be the nature of efficient
causality, _actio_ and _passio_ (102), or of the dependence of the
produced actuality upon the active power of its adequate efficient cause
(10), the reality of this dependence forbids us to think that in the
natural order of efficient causation a higher grade of reality can be
actualized than the agent is capable of actualizing, or that the agent can
naturally actualize a higher or more perfect grade of reality than is
actually its own. We must, however, bear in mind that there is question of
the _adequate_ created cause of an effect; and that to account _fully_ for
the actualization of any potential reality whatsoever we are forced to
recognize in all causation of created efficient causes the _concursus_ of
the _First Cause_.
(_d_) The actuality of the effect is in its adequate created cause or
causes, _not actually and formally, but potentially_ or _virtually_. If
the cause produce an effect of the same kind as itself (_causa
____univoca___), as when living organisms propagate their species, the
perfection of the effect is said to be in the cause _equivalently_
(_aequivalenter_); if it produce an effect of a different kind from itself
(_causa ____analoga___), as when a sculptor makes a statue, the perfection
of the effect is said to be in the cause _eminently_ (_eminenter_).
(_e_) _Omne agens agit inquantum est in actu._ The operative power of a
being is in proportion to its own actual perfection: the higher an agent
is on the scale of reality, or in other words the more perfect its grade
of being, the higher and more perfect will be the effects achieved by the
exercise of its operative powers. In fact our chief test of the perfection
of any nature is analysis of its operations. Hence the maxim so often
referred to already:—
(_f_) _Operari sequitur esse; qualis est operatio talis est natura; modus
operandi sequitur modum essendi._ Operation is the key to nature; we know
what any thing is by what it does.
(_g_) _Nihil agit ultra suam speciem_; or, again, _Omne agens agit simile
sibi_. These are inductive generalizations gathered from experience, and
have reference to the natural operation of agents, especially in the
organic world. Living organisms reproduce only their own kind. Moreover,
every agency in the universe has operative powers of a definite kind;
acting according to its nature it produces certain effects and these only;
others it cannot produce: this is, in the natural order of things, and
with the natural _concursus_ of the First Cause. But created causes have a
passive _obediential capacity_ (_potentia obedientialis_) whereby their
nature can be so elevated by the First Cause that they can produce, with
His special, supernatural _concursus_, effects of an entirely higher order
than those within the ambit of their natural powers.(454)
(_h_) From a known effect, of whatsoever kind, we can argue with
certainty, _a posteriori_, to the _existence_ of an adequate efficient
cause, and to _some knowledge_ of the _nature_ of such a cause.(455) By
virtue of the principle of causality we can infer the existence of an
adequate cause containing either equivalently or eminently all the
perfections of the effect in question.
99. CLASSIFICATION OF EFFICIENT CAUSES.—(_a_) We have already referred to
the distinction between the _First_ Cause and _Second_ or _Created_
Causes. The former is absolutely independent of all other beings both as
to His power and as to the exercise of this power. The latter are
dependent, for both, upon the former.
The distinction between a first, or primary, or independent cause, and
second, or subordinate, or dependent causes can be understood not only of
causes universally, but also as obtaining among created causes themselves.
In general the _subordination_ of a cause to a superior or anterior cause
may be either _essential_ or _accidental_: essential, when the second
cause depends—either for its existence or for an indispensable complement
of its efficiency—on the _present_ actual influence of the other cause;
accidental when the second cause has indeed received its existence or
efficiency from this other cause, but is now no longer dependent, for its
existence or action, on the latter. Thus, living organisms are, as causes,
accidentally subordinate to their parent organisms: they derived their
existence from the latter, but are independent of these when in their
maturity they continue to exist, and live, and act of themselves and for
themselves. But all creatures, on the other hand, are, as causes,
_essentially_ subordinate to the Creator, inasmuch as they can exist and
act only in constant dependence on the ever present and ever actual
conserving and concurring influence of the Creator.
It is obvious that all the members of any series of causes _essentially_
subordinate the one to the other _must exist simultaneously_. Whether such
a series could be infinite depends, therefore, on the question whether an
_actually infinite multitude_ is intrinsically possible. This difficulty
cannot be urged with such force against an infinite regress in causes
_accidentally_ subordinate to one another; for here such a regress would
not involve an actually infinite multitude of things existing
simultaneously. In the case of essentially subordinate causes, moreover,
the series, whatever about its infinity, must contain, or rather imply
_above_ it, _one_ cause which is _first_ in the sense of being
_independent_, or exempt from the subordination characteristic of all the
others. And the reason is obvious: Since no one of them can exist or act
except dependently on another, and this on another, and so on, it is
manifest that the series cannot exist at all unless there is some one
cause which, unlike all the others, exists and acts without such
subordination or dependence. Hence, _in essentially subordinate causes an
infinite regress is impossible_.(456) In Natural Theology these
considerations are of supreme importance.
(_b_) An efficient cause may be described as _immanent_ or _transitive_
according as the term of its action remains within the cause itself, or is
produced in something else. The action of the First Cause is formally
immanent, being identical with the Divine Nature itself; it is virtually
transitive when it is creative, or operative among creatures.
(_c_) An efficient cause is either a _principal_ or an _instrumental_
cause. When two causes so combine to produce an effect that one of them
uses the other the former is called the principal and the latter the
instrumental cause. Thus I am the principal cause of the words I am
writing; my pen is the instrumental cause of them. Such an effect is
always attributed to the principal cause, not to the instrumental. The
notion of an instrument is quite a familiar notion. An instrument helps
the principal agent to do what the latter could not otherwise do, or at
least not so easily. An instrument therefore is really a cause. It
contributes positively to the production of the effect. How does it do so?
By reason of its nature or structure it influences, modifies, and directs
in a particular way, the efficiency of the principal cause. But this
property of the instrumental cause comes into play only when the latter is
being actually used by a principal cause. A pen, a saw, a hammer, a spade,
have each its own instrumentality. The pen will not cut, nor the saw mould
iron, nor the hammer dig, nor the spade write, for the agent that uses
them. Each will produce its own kind of effect when used; but none of them
will produce any effect except when used: though each has in itself
permanently and inherently the power to produce its own proper effect in
use.(457) We have instanced the use of _artificial_ instruments. But
nature itself provides some agencies with what may be called _natural_
instruments. The _semen_ whereby living organisms propagate their kind is
an instance. In a less proper sense the various members of the body are
called instruments of the human person as principal cause, “instrumenta
_conjuncta_”.
The notion of an instrumental cause involves then (_a_) subordination of
the latter, in its instrumental activity, to a principal cause, (_b_)
incapacity to produce the effect otherwise than by modifying and directing
the influence of the principal cause. This property whereby the
instrumental cause modifies or determines in a particular way the
influence of the principal cause, is called by St. Thomas an _actio_ or
_operatio_ of the former; the distinction between the principal and the
instrumental cause being that whereas the former acts by virtue of a power
permanently inherent in it as a natural perfection, the latter acts as an
instrument only by virtue of the transient motion which it derives from
the principal cause which utilizes it.(458)
We may, therefore, define an _instrumental_ cause as _one which, when
acting as an instrument, produces the effect not by virtue of its inherent
power alone, but by virtue of a power communicated to it by some principal
cause which acts through it_. A _principal_ cause, on the other hand, is
_one which produces its effect by virtue of an active power permanently
inherent in itself_.
The designations _principal_ and _instrumental_ are obviously correlative.
Moreover, _all created_ causes may be called _instrumental_ in relation to
the _First Cause_. For, not only are they dependent on the latter for the
_conservation_ of their nature and active powers; they are also dependent,
in their action, in their actual exercise of these powers, on the First
Cause (for the _concursus_ of the latter).(459) Yet some created causes
have these powers permanently, and can exercise them without subordination
to other creatures; while others need, for the exercise of their proper
functions, not only the Divine _concursus_, but also the motion of other
creatures. Hence the former are rightly called _principal_ created causes,
and the latter _instrumental_ created causes.
(_d_) Efficient causes are divided into _free_ causes and _necessary_
causes. A free or self-determining cause is _one which is not determined
by its nature to one line of action_, but _has the power of choosing, or
determining itself_, to act or abstain, when all the conditions requisite
for acting are present. Man is a free agent, or free cause, of his
deliberate actions. A necessary cause, or natural cause as it is sometimes
called, is _one which is determined by its nature to one invariable line
of action_, so that, granted the conditions requisite for action, it
cannot naturally abstain from acting in that invariable manner. All the
physical agencies of the inorganic world, all plant and animal organisms
beneath man himself, are necessary causes.
The freedom of the human will is established against determinism in
Psychology.(460) The difficulties of determinists against this doctrine
are for the most part based on misconceptions, or on erroneous and
gratuitous assumptions. We may mention two of them here.(461) Free
activity, they say, would be _causeless_ activity: it would violate the
“law of universal causation”. We reply that free activity is by no means
causeless activity. The free agent himself is in the fullest and truest
sense the efficient cause of his free acts. It is by his causal, efficient
influence that the act of free choice is determined and elicited. Free
causality evidently does not violate the necessary, _a priori_ principle
set forth above under the title of the Principle of Causality. But—they
urge in the second place—it violates the “law of universal causation,”
_i.e._ the law that every event in nature must be the result of some set
of phenomenal antecedents which _necessitate_ it, and which, therefore,
whenever verified, _must_ produce this result and no other; and by
violating this law it removes all supposed “free” activities from the
domain of that regularity and uniformity without which no scientific
knowledge of such phenomena would be possible. To this we reply, firstly,
that the law of uniform causation in nature, the law which is known as the
“Law of the Uniformity of Nature,” and which, under the title of the “Law
of Universal Causation” is confounded by determinists and phenomenists
with the entirely distinct “Principle of Causality”—is not by any means a
law of _necessary_ causation.(462) The statement that Nature is uniform in
its activities is not the expression of an _a priori_, necessary truth,
like the Principle of Causality. It is a generalization from experience.
And experience testifies to the existence of grades in this all-prevailing
uniformity. In the domain of physical nature it is the expression of the
Free Will of the Author of Nature, who may miraculously derogate from this
physical uniformity for higher, moral ends. In the domain of deliberate
human activities it is the expression of that less rigorous but no less
real uniformity which is dependent on the free will of man. And just as
the possibility of miracles in the former domain does not destroy the
regularity on which the generalizations of the physical sciences are
based, so neither does the fact of human free will render worthless or
unreliable the generalizations of the human sciences (ethical, social,
political, economic, etc.) about human conduct. Were the appearance of
miracles in the physical domain, or the ordinary play of free will in the
human domain, entirely _capricious_, _motiveless_, _purposeless_, the
results would, of course, be chaotic, precarious, unaccountable,
unintelligible, and scientific knowledge of them would be impossible: for
the assumption that reality is the work of intelligent purpose, and is
therefore a regular, orderly expression of law, in other words, the
assumption that the universe is intelligible, is a prerequisite condition
for scientific knowledge about the universe. But determinists seem to
assume that Divine Providence and human free will must necessarily imply
that the whole universe of physical phenomena and human activities would
be an unintelligible chaos; and having erected this philosophical
scarecrow on a gratuitous assumption they think it will gradually exorcise
all belief in Divine Providence and human freedom from the “scientific”
mind!
(_e_) Efficient causes are either _physical_ or _moral_. A physical
efficient cause is _one which produces its effect by its own proper power
and action_—whether immediately or by means of an instrument. For
instance, the billiard player is the physical cause of the motion he
imparts to the balls by means of the cue. A moral cause is one which
produces its effect by the representation of something as good or evil to
the mind of a free agent; by inducing the latter through example, advice,
persuasion, promises, threats, commands, entreaties, etc., to produce the
effect in question. For instance, a master is the moral cause of what his
servant does in obedience to his commands. The motives set forth by way of
inducement to the latter are of course _final_ causes of the latter’s
action. But the former, by setting them forth, is the moral cause of the
action: he is undoubtedly more than a mere condition; he contributes
positively and efficiently to the effect. His physical causation, however,
does not reach to the effect itself, but only to the effect wrought in the
mind of the servant by his command. It is causally connected with the
physical action of the servant by means of an intermediate link which we
may call _mental_ or _psychical causation_—_actio_ “_intentionalis_,”—the
action of cognition on the mind of a cognitive agent.
The agent employed by a moral cause to produce an effect physically may be
called an instrumental cause in a wide and less proper sense of this term,
the instrumentality being moral, not physical. Only free agents can be
moral causes; and as a rule they are termed moral causes only when they
produce the effect through the physical operation of another free agent.
What if they employ not free agents, nor yet inanimate instruments, but
agents endowed with sense cognition and sense appetite, to produce
effects? If a man set his dog at another, is he the _moral_ or the
_physical_ cause of the injuries inflicted by the dog? That he is the
principal _efficient_ cause is unquestionable. But is he the principal
_physical_ cause and the dog the _instrument_? We think it is more proper
to call the principal efficient cause a _moral_ cause in all cases where
there intervenes between his physical action and the effect an
intermediate link of “psychical” or “intentional” action, even though, as
in the present example, this psychical link is of the sentient, not the
intellectual, order.
(_f_) The efficient cause, like other causes, may be either _partial_ or
_total_, according as it produces the effect by co-operation with other
causes, or by itself alone. The aim of the inductive sciences is to
discover for each kind of natural event or phenomenon the “total cause” in
the comprehensive sense of the whole group of _positive_ agencies or
causes proper, and _negative_ antecedent and concomitant _conditions_
which are _indispensable_ and _necessitating_ principles of the happening
of such kind of event.(463)
(_g_) We can distinguish between the _immediate or determining_, the more
or less _proximate_, and the more or less _remote_, efficient causes of an
event. Thus, the application of the fuse to the charge of dynamite in a
rock is the immediate or determining cause of the explosion which bursts
the rock; the lighting of the fuse, the placing of the charge, etc., the
more proximate causes; the making of the fuse, dynamite, instruments,
etc., the more remote causes. Again the aim of the inductive sciences is
to discover the “total _proximate_ cause” of events,(464) leaving the
investigation of ultimate causes, as well as the analysis of causality
itself, to philosophy.
(_h_) Finally, we must distinguish between the _individual_ agent itself
as cause (the _suppositum_ or person that acts); the agent’s _nature_ and
_active power_ as causes; and the _action_, or exercise of this power as
cause. The former, the individual, concrete agent, is the “principium
_quod_ agit,” and is called the “causa _ut quae_”. The nature and the
active power of the agent are each a “principium _quo_ agens agit,” the
remote and the proximate principle of action respectively; and each is
called a “causa _ut qua_”. The action of the agent is the cause of the
effect in the sense that the actual production or _fieri_ of anything is
the immediate cause of this thing _in facto esse_. Corresponding to these
distinctions we distinguish between the cause _in actu primo remoto_, _in
actu primo proximo_, and _in actu secundo_. These distinctions are of no
little importance. By ignoring them, and by losing sight of the intrinsic
(formal and material) causes of natural phenomena, many modern scientists
and philosophers have confounded cause and effect with the process itself
of causation, and declared that cause and effect are not distinct
realities, but only two mental aspects of one and the same reality.(465)
The same may be said of all the distinctions so far enumerated.
They are absolutely essential to the formation of clear ideas on
the question of causality. No term in familiar use is of more
profound philosophical significance, and at the same time more
elastic and ambiguous in its popular meanings, than the term
_cause_. This is keenly felt in the Logic of the Inductive
Sciences, where not only the discovery, but the exact measurement,
of physical causes, is the goal of research.
“When we call one thing,” writes Mr. Joseph,(466) “the cause of
another, the real relation between them is not always the same....
We say that molecular action is the cause of heat, that the heat
of the sun is the cause of growth, that starvation is sometimes
the cause of death, that jealousy is a frequent cause of crime. We
should in the first case maintain that cause and effect are
reciprocally necessary; no heat without molecular motion and no
molecular motion without heat. In the second the effect cannot
exist without the cause, but the cause may exist without the
effect, for the sun shines on the moon but nothing grows there. In
the third the cause cannot exist without the effect, for
starvation must produce death, but the effect may exist without
the cause, since death need not have been produced by starvation.
In the fourth case we can have the cause without the effect, and
also the effect without the cause; for jealousy may exist without
producing crime, and crime may occur without the motive of
jealousy. It is plain then that we do not always mean the same
thing by our words when we say that two things are related as
cause and effect; and anyone who would classify and name the
various modes in which two things may be causally related would do
a great service to clear thinking.”
In the popular acceptation of the term _cause_, the same kind of
event can have a _plurality of (efficient) causes_. Death, for
example, may be brought about in different cases by different
diseases or accidents. But if we understand by the total efficient
cause of any given kind of effect the sum-total of agencies and
conditions which when present _necessitate_ this kind of an
effect, and which are collectively and severally _indispensable_
for its production, then it is obvious that a given _kind_ of
effect can have _only one kind_ of such total group of antecedents
as total cause, just as any one individual effect can have only
one individual total cause, _viz._ the one which actually produced
it; a _similar_ total cause would produce a _similar_ effect, but
could not produce the numerically identical individual effect of
the other similar cause.(467)
The medieval scholastics discussed the question in connexion with
the problem of individuation: “Would Alexander the Great have been
the same individual had he been born of other parents than Philip
and Olympia?” The question is hardly intelligible. The person born
of these other parents might indeed have been as similar as you
will to the actual Alexander of history, but would not and could
not have been the actual Alexander of history. Nowadays the
question discussed in this connexion is not so much whether the
same kind of natural phenomenon can be produced by different kinds
of total cause—for the answer to this question depends wholly on
the wider or the narrower meaning attached to the term “total
cause,”(468)—but rather whether or how far the inductive
scientist’s ideal of searching always for the _necessitating and
indispensable_ cause (or, as it is also called, the
“reciprocating” or “commensurate” cause) is a practical ideal.