Five Ways (Aquinas)

The Quinque viæ (Latin for "Five Ways") (sometimes called "five proofs") are five logical arguments for the existence of God summarized by the 13th-century Catholic philosopher and theologian Thomas Aquinas in his book Summa Theologica.

They are: Aquinas expands the first of these – God as the "unmoved mover" – in his Summa Contra Gentiles.

[6] The Summa uses the form of scholastic disputation (i.e. a literary form based on a lecturing method: a question is raised, then the most serious objections are summarized, then a correct answer is provided in that context, then the objections are answered).

A subsequent, more detailed, treatment of the Five Ways can be found in the Summa contra gentiles.

[9]His thinking here relies on what would later be labelled "essentially ordered causal series" by John Duns Scotus.

[6][13] Aquinas uses the term "motion" in his argument, but by this he understands any kind of "change", more specifically a transit from potentiality to actuality.

[6][13] The argument begins with the observation that things around us come into and go out of existence: animals die, buildings are destroyed, etc.

Some interpreters read Aquinas to mean that assuming an infinite past, all possibilities would be realized and everything would go out of existence.

[6][13] The argument is rooted in Aristotle and Plato but its developed form is found in Anselm of Canterbury's Monologion.

[19][20] Although the argument has Platonic influences, Aquinas was not a Platonist and did not believe in the Theory of Forms.

The oak tree is the "end" towards which the acorn "points," its disposition, even if it fails to achieve maturity.

The latter implicitly argue that objects in the world do not have inherent dispositions or ends, but, like Paley's watch, will not naturally have a purpose unless forced to due some outside agency.

[26] The latter also focus on complexity and interworking parts as the effect needing explanation (e.g., that an eye has a complicated function therefore a design therefore a designer), whereas the Fifth Way takes as its starting point any regularity[26] (e.g., that the pattern that things exist with a purpose itself allows us to recursively arrive at God as the ultimate source of purpose without being constrained by any external purpose).

Many scholars and commenters caution against treating the Five Ways as if they were modern logical proofs.

Reasons include: A demonstration in Aristotle is a syllogism that produces scientific knowledge.

This means that one may have cognition that something is true which is quite certain without having scientific knowledge...[30]Criticism of the cosmological argument, and hence the first three Ways, emerged in the 18th century by the philosophers David Hume and Immanuel Kant.

[39][40] The 20th-century philosopher of religion Richard Swinburne argued in his book, Simplicity as Evidence of Truth, that these arguments are only strong when collected together, and that individually each of them is weak.

[41] The 20th-century Catholic priest and philosopher Frederick Copleston devoted much of his work to a modern explication and expansion of Aquinas' arguments.

More recently the prominent Thomistic philosopher Edward Feser has argued in his book Aquinas: A Beginner's Guide that Richard Dawkins, Hume, Kant, and most modern philosophers do not have a correct understanding of Aquinas at all; that the arguments are often difficult to translate into modern terms.

Sobel offers objections to the first three Ways by challenging the notion of sustaining efficient causes and a concurrent actualizer of existence.

[44] Atheist philosopher Graham Oppy has offered critiques of the arguments in his exchanges with Edward Feser and in his published work.

[45] Biologist Richard Dawkins' book The God Delusion argues against the Five Ways.

According to Dawkins, "[t]he five 'proofs' asserted by Thomas Aquinas in the thirteenth century don't prove anything, and are easily [...] exposed as vacuous.

For example, for the fifth Way, Dawkins places it in the same position for his criticism as the watchmaker analogy, when in fact, according to Ward, they are vastly different arguments.

[47] Eastern Orthodox theologian David Bentley Hart says that Dawkins "devoted several pages of The God Delusion to a discussion of the 'Five Ways' of Thomas Aquinas but never thought to avail himself of the services of some scholar of ancient and medieval thought who might have explained them to him ... As a result, he not only mistook the Five Ways for Thomas's comprehensive statement on why we should believe in God, which they most definitely are not, but ended up completely misrepresenting the logic of every single one of them, and at the most basic levels.

"[48] Hart said of Dawkins treatment of Aquinas' arguments that: Not knowing the scholastic distinction between primary and secondary causality, for instance, [Dawkins] imagined that Thomas's talk of a "first cause" referred to the initial temporal causal agency in a continuous temporal series of discrete causes.