The Fifth Way: from natural finality to Divine Intelligence

Natural agents act regularly toward determinate effects. An electron, acid, seed, eye and intellect do not produce an arbitrary range without structure. Their powers are specified by characteristic acts. This directedness is final causality.

Non-intelligent agents do not understand the universal relations in which their powers operate. They cannot be the ultimate source of the intelligible order of natures, laws and ends. Their direction is received with their forms and powers.

An intelligent source is required, not because every natural object resembles a human artifact, but because determinate causal orientation is intelligible only through relation to an end. Intelligence alone can contain an end universally and order means toward it as end.

The ordering intelligence is the cause of intrinsic natural finality. God does not merely impose external motions on passive matter. He gives things the natures by which they act for themselves as genuine secondary causes.

Reader path: Aquinas, Fifth Way · Aristotle, Physics II

A power is identified by what it can do. Sight is a power for receiving visible form; nutrition is ordered to sustaining life; gravity is specified by determinate interactions. Remove the relation to act and the word power becomes empty.

Final cause is therefore not always a conscious future event pulling the present. It is the act that specifies the potency and the good under whose aspect a process is intelligible. In intentional action the end is consciously represented; in nature it is embodied in form and power.

Chance does not eliminate finality. A stone accidentally strikes a plant because two causal lines intersect. Each line still contains determinate powers and tendencies. Chance is parasitic upon order and cannot explain the universal existence of ordered powers.

Mechanistic description abstracts from finality to calculate efficient relations. The abstraction can be fruitful, but it should not be converted into the claim that no directed powers exist. A machine itself functions only because parts possess powers ordered within a whole.

First premise: non-intelligent natural agents regularly act toward determinate ranges of effects according to stable powers.

Second premise: acting toward a determinate effect manifests finality, because the potency is specified by the act and the process is intelligible through its terminus.

Third premise: non-intelligent agents do not apprehend the universal order and cannot be the ultimate source of their own formal direction.

Fourth premise: the order of natures and ends cannot be wholly derivative without an intelligent source in which the forms and relations are present eminently.

Conclusion: there exists an ordering intelligence that causes natural beings to possess intrinsic powers and ends. Joined to the other ways, this intelligence is the simple first cause and pure act.

Natural selection explains why heritable traits that contribute to reproductive success become prevalent. The explanation presupposes organisms, reproduction, inheritance, variation, environments and functions. Each term is teleological or formal in the broad metaphysical sense.

A heart has the function of circulating blood because it belongs to an organism whose parts are ordered to life. Evolutionary history can explain how the organ developed without making its present function a subjective projection. Etiological and systems accounts of function both rely upon real organized ends.

The Fifth Way does not require that every biological structure be separately designed without secondary causes. Divine intelligence can order a world in which forms arise through natural processes. The more fecund the created powers, the more deeply providence is expressed.

Disorder, extinction and suffering raise questions about providence and goodness, but they do not show absence of finality. Failure is intelligible only relative to an end: a malformed eye fails because eyes are for seeing. Privation presupposes the very order it damages.

A law can mean a human proposition summarizing observations, a mathematical relation, or a real regularity grounded in powers. None of these alternatives explains itself. Human propositions are effects of minds; mathematical relations do not efficiently create concrete systems; real structures are precisely the order requiring ground.

Information is always information in a formal system and often for an interpreter or function. DNA sequences operate within a cellular machinery whose components and ends determine significance. Calling the sequence information highlights form and relation rather than reducing them to matter.

The universe's intelligibility to human mathematics also deserves attention. The mind and nature share formal order sufficiently for abstract reasoning to predict phenomena. This correspondence is expected if both proceed from intelligence; it is difficult to treat as an ultimate accident without explanation.

The Fifth Way does not infer God from the current inability to explain one code. It asks why any natural code, law or power has determinate intelligible orientation. Scientific discoveries supply richer examples but do not create the metaphysical principle.

If the first intelligence causes natures, powers and ends, its causal presence is interior to every natural action. The creature operates by its own form precisely because that form and act are caused. Providence is therefore compatible with natural autonomy.

Divine knowledge does not observe a world external to its causal act and then react. God knows creatures by knowing His essence as their exemplary and efficient cause. The whole order is present to one eternal act.

Contingency and freedom are included within providence according to their modes. God causes necessary effects necessarily through secondary causes and contingent effects contingently. Divine universality does not flatten the diversity of created causality.

The Fifth Way thus moves beyond a watchmaker who constructs and abandons a mechanism. The first intelligence continuously causes the intelligible order and directs creatures toward ends, while allowing defects proper to finite secondary causes within a greater order.

The immediate conclusion is an intelligent source of natural order. Because the order extends universally across created natures and powers, the source is not a local designer within the cosmos.

Joined to the first four ways, the ordering intelligence is pure act, first cause, necessary being and unparticipated goodness. It does not receive ideas from a prior realm; the forms of creatures exist eminently in the divine intellect.

Divine will follows intelligence. Creation is a free communication of goodness, not a necessary overflow that makes the world part of God. Providence orders each creature according to its nature and the common good of the whole.

The completed five-way argument now permits the next stage: whether this intelligent and good Creator has revealed Himself through public signs in history. Natural theology has not proved Christianity, but it has shown that revelation and miracle cannot be dismissed as metaphysically impossible.