This error was not unknown in the Middle Ages,[490] but it was in the seventeenth century that certain disciples of Descartes,—Geulincx (1625-1669) and Malebranche (1638-1715),—expressly inferred it from the Cartesian antithesis of matter and spirit and the Cartesian doctrine that matter is essentially inert, or inactive. According to the gratuitous and unproven assertion laid down by Geulincx as a principle: Quod nescis quomodo fiat, id non facis,—we do not cause our own sensations or reasoning processes, nor our own bodily movements, inasmuch as we do not know how these take place; nor can bodies cause them, any more than our own created spirits, inasmuch as bodies are essentially inactive. According to Malebranche the mind can perceive no necessary nexus between effects and any cause other than the Divine Will;[491] moreover reflection convinces us that efficient causality is something essentially Divine and incommunicable to creatures;[492] and finally neither bodies can be causes, for they are essentially inert, nor our minds and wills, for we do not know how a volition could move any organ or member of our bodies.[493] Yet Malebranche, at the cost of inconsistency with his own [pg 398] principles, safeguards free will in man by allowing an exclusively immanent efficiency to spiritual causes.[494]
Such is the teaching of Occasionalism. Our criticism of it will be brief.[495]
(1) Against the doctrine that creatures generally are not, and cannot be, efficient causes, we direct the first argument already outlined ([100]) against Phenomenism and Positivism,—the argument from the universal belief of mankind, based on the testimony of consciousness as rationally interpreted by human intelligence. Consciousness testifies not merely that processes of thought, imagination, sensation, volition, etc., take place within our minds; not merely that our bodily movements, such as speaking, walking, writing, occur; but that we are the causes of them.[496] It is idle to say that we do not efficiently move our limbs because we may not be able to understand or explain fully “how an unextended volition can move a material limb”.[497] Consciousness testifies to the fact that the volition does move the limb; and that is enough.[498] The fact is one thing, the quomodo of the fact is quite another thing. Nor is there any ground whatever for the assertion that a cause, in order to produce an effect, must understand how the exercise of its own efficiency brings that effect about. Moreover, Malebranche's concession of at least immanent activity to the will is at all events an admission that there is in the nature of the creature as such nothing incompatible with its being an efficient cause.
(2) Although Malebranche bases his philosophy mainly on deductive, a priori reasonings from a consideration of the Divine attributes, his system is really derogatory to the perfection of the First Cause, and especially to the Divine Wisdom. To say, for instance, that God created an organ so well adapted to discharge the function of seeing as the human eye, and then to deny that the latter discharges this or any function, is tantamount to accusing God of folly. There is no reason in this system why any created thing or condition of things would be even the appropriate occasion of the First Cause producing any definite effect. Everything would be an equally appropriate occasion, or rather nothing would be in any intelligible sense an appropriate occasion, for any exercise of the Divine causality. The admirable order of the universe—with its unity in variety, its adaptation of means to ends, its gradation of created perfections—is an intelligible manifestation of the Divine perfections on the assumption that creatures efficiently co-operate with the First Cause in realizing and maintaining this order. But if they were all inert, inoperative, useless for this purpose, what could be the raison d'être of their diversified endowments and perfections? So far from manifesting the wisdom, power and goodness of God they would evidence an aimless and senseless prodigality.
(3) Occasionalism imperils the distinction between creatures and a personal God. Although Malebranche, fervent catholic that he was, protested against the pantheism of “le misérable Spinoza,” his own system contains the undeveloped germ of this pernicious error. For, if creatures are not efficient causes not only are their variety and multiplicity meaningless, as contributing nothing towards the order of the universe, but their very existence as distinct realities seems to have no raison d'être. Malebranche emphasizes the truth that God does nothing useless: Dieu ne fait rien d'inutile. Very well. If, then, a being does nothing, what purpose is served by its existence? Of what use is it? What is the measure of a creature's reality, if not its action and its power of action? So intimately in fact is this notion of causality bound up with the notion of the very reality of things that the concept of an absolutely inert, inactive reality is scarcely intelligible. It is almost an axiom in scholastic philosophy that every nature has its correlative activity, every being its operation: Omne ens est propter suam operationem; Omnis natura ordinatur ad propriam operationem. Hence if what we call creatures had [pg 400] really no proper activity distinct from that of the First Cause, on what grounds could we suppose them to have a real and proper existence of their own distinct from the reality of the Infinite Being? Or who could question the lawfulness of the inference that they are not really creatures, but only so many phases, aspects, manifestations of the one and sole existing reality? Which is Pantheism.
(4) Occasionalism leads to Subjective Idealism by destroying all ground for the objective validity of human science. How do we know the real natures of things? By reasoning from their activities in virtue of the principle, Operari sequitur esse.[499] But if things have no activities, no operations, such reasoning is illusory. How, for instance, do we justify by rational demonstration, in opposition to subjectivism, the common-sense interpretation of the data of sense consciousness as revealing to us the real and extramental existence of a material universe? By arguing, in virtue of the principle of causality, from our consciousness of our own passivity in external sense perception, to the real existence of bodies outside our minds, as excitants of our cognitive activity and partial causes of these conscious, perceptive processes. But if occasionalism were true such inference would be illusory, and we should infer, with Berkeley, that only God and minds exist, but not any material universe. Malebranche admits the possible validity of this inference to immaterialism from his principles, and grounds his own belief in the existence of an external material universe solely on faith in Divine Revelation.[500]
It only remains to answer certain difficulties urged by occasionalists against the possibility of attributing real efficiency to creatures.
(1) They argue that efficient causality is something essentially Divine, and therefore cannot be communicated to creatures.
We reply that while the absolutely independent causality of the First Cause is essentially Divine, another kind or order of causality, dependent on the former, but none the less real, can be and is communicated to creatures. And just as the fact that creatures have real being, real existence, distinct from, but dependent on, the existence of the Infinite Being, does not derogate from the supremacy of the latter, so the fact that creatures have real efficient causality, distinct from, but dependent on, the causality of the First Cause, does not derogate from the latter's supremacy.
(2) They urge that efficient causality is creative, and therefore infinite and incommunicable.