The intrinsic purposefulness of life must have an extrinsic source

The title plays on a remark that Rope Kojonen made in a recent workshop on New Perspectives on Evolution, Teleology, and Theology, 28-30. September 2026: 

Intrinsic teleology with an extrinsic source.

For elaboration of what is meant by intrinsic and extrinsic teleology see my previous blog post. 

Kojonen's remark is exactly what I describe in the following excerpt from "Chapter 6 Evolution and Purpose" of The Imagined Conflict:

Thomas Aquinas’s Fifth Way

Aquinas combined Aristotle’s thoughts with a Christian worldview. He also gave an explanation for why there could be intrinsic purposefulness in all of life. He did not accomplish this by stating that purposefulness was directly imposed on all things by a deity, as in Platonic thought. In a clever way he justified Aristotle’s idea of intrinsic purposefulness by saying that there must be a reason for such ubiquitous purposefulness. This is the topic of the last of the five ways (see chapter 2*), known as “the teleological way.” Since this argument about purpose is often confused with the argument that complexity points toward God, it is worth quoting in full here:

We see that things which lack intelligence, such as natural bodies, act for an end, and this is evident from their acting always, or nearly always, in the same way, so as to obtain the best result. Hence it is plain that not fortuitously, but designedly, do they achieve their end. Now whatever lacks intelligence cannot move towards an end, unless it be directed by some being endowed with knowledge and intelligence; as the arrow is shot to its mark by the archer. Therefore some intelligent being exists by whom all natural things are directed to their end; and this being we call God.

This applies to all non-intelligent objects and beings, which for Aquinas meant everything except humans.

Aquinas asserts that since there are beings with these inclinations—these purposes—built into them, we can conclude that there must exist a God who is the reason for the very existence of purpose. In modern language, we might say that life has built-in information that has the codes required for this very purpose. But the purposefulness is more than just information; it is such an integral part of life and every organ, whether we understand it scientifically or not, that life without it is inconceivable. It is not something that needs to be added from the outside in each individual case. Aquinas says that this points beyond each individual being to God as the source of this purposefulness.

This argument differs from a complexity argument. All life, whether complex or what we regard as simple, possesses this intrinsic purposefulness which indirectly points to God. Nevertheless, Aquinas’s  fifth way is often interpreted narrowly to mean that just complexity points to God; but it is much wider than that. 

* Chapter 2 introduces Aquinas' five ways like this:
Thomas Aquinas (1225–1274) is known for outlining five ways or arguments for the existence of God. Some people call them proofs, but Aquinas himself seems to present them merely as expressions of God’s nature. The fifth way deals with purpose in nature. It is also called the teleological way.