Aquinas's Five Ways: Reason, Faith, and Their Limits

Introduction

The Five Ways — Thomas Aquinas's celebrated arguments for the existence of God — are widely regarded as some of the most practical and substantive philosophical proofs ever composed on the subject. Though they possess considerable merit, the reality of each argument both begins and ends with simple faith. The reader or philosopher is ultimately left to interpret Aquinas's logic through statements that all conclude with an assumption of faith, making faith the very structure and skeleton of his proofs.

Though his works are well thought out, they were created in an era when questioning ultimate truths was virtually unheard of. The faith of Aquinas, and of the whole period in which he wrote, is assumed throughout the dialogue of his proofs, in many ways reducing each individual proof to yet another representation of faith. This paper will briefly explain and define each proof and then attempt to demonstrate the point at which faith enters each of the Five Ways and the arguments associated with it.

In the entire set of proofs, Aquinas demonstrates the use of reason and scientific thought. He spends considerable effort formulating, both for himself and for the reader, explanations of each preceding assertion. With or without these explanations, it is clear that he is speaking to an audience that both assumes and believes that God exists. Even today, "many human beings have reasons for such a belief that are informal versions of one of the five ways; they suppose, for example, that because there is order in the universe there must be a principle of order" (Hibbs 573).

The First Way: Motion and Change

In the First Way, Aquinas relates the existence of God to the process of change. He states that within this world all people admit that things exist which are in the process of change, and that this change is initiated by a force other than the thing itself. Aquinas then argues that if this is the case — and he asserts that it obviously is — there must have been an initial force that changed something into something else, because a thing cannot simultaneously be what it is and what it has the potential to be.

Closing the argument, Aquinas attributes the property of this initial force of change to God, since the process cannot be infinite in either direction and must therefore have a finite first cause. "So we have to come to some first initiator of change which is not in a process of change initiated by something else, and everyone understands that this is God" (Martin 134).

Clearly, Aquinas frames his argument within a particular historical context, charging "everyone" with a belief in God and thus invoking a blindly assumed tenet of reality — an unchangeable fact of life. Refutation of this argument is fairly straightforward and accepted by millions: the very nature of faith is that it is blind. Faith cannot be affirmed by proof, because once it is proven it is no longer faith.

The Second Way: Efficient Cause

In the Second Way, Aquinas comes closest to outlining what many would consider the law of nature. Within nature there is a pattern or order of things and events; these patterns are observable and tend to exemplify the best possible outcomes repeatedly. The principle at work here is that if this kind of optimal order or pattern exists, there must be a source of that plan — and that source would be the divine.

The Second Way attempts to demonstrate a clear link between the notion of efficient cause and an ultimate source for such a cause. Excluding itself as the source of the efficient cause, Aquinas once again assumes the existence of a divine power called God who defines and embodies the initial and continuing most-efficient cause:

"We find, in things around us that we sense, an order of efficient causes. But we do not find — nor could there be — anything that is the efficient cause of itself. For if anything were, it would have to be prior to itself, and this is impossible." (Martin 150)

Once again Aquinas dismisses the infinite by asserting simply that people must exclude it as a possibility. The simplest argument against this is that human beings, as finite minds, are simply unable to conceive of the infinite — a testament to the limitations of the human mind rather than to the finite nature of the universe. Finitude must assume a series of causes — first, last, and intermediary — and according to Aquinas the only possible solution is that God is the initial efficient cause. "Hence we must suppose some first efficient cause, and this is what all call 'God'" (Martin 151).

Conclusion

Challenging faith is nearly always a very serious endeavor. The ideals associated with Thomas Aquinas's Five Ways are clearly shaped by his era's scientific assumptions and the representative faith of his time. With or without the expression of his logical thought, the remaining formation of each Way is eventually reduced to an expression of faith.