Foundations in Environmental Ethics: Aquinas and Anthropocentrism

In this video, Professor Thorsby discusses the anthropocentrism of Thomas Aquinas.

Welcome to this lesson on Thomas Aquinas and the concept of humans as moral ends. Aquinas represents a medieval theological foundation for anthropocentrism. His central claim is that rational creatures—humans—are cared for by divine providence for their own sake, while non-rational beings exist for the sake of humans. This hierarchy sets humans apart as moral ends, while animals, plants, and the rest of creation are treated as instruments.

Aquinas argues that because humans are endowed with intellect and free will, they alone reflect the divine likeness and approach God as the ultimate end. Other beings, lacking rationality, serve humans just as tools serve the craftsman. This framework legitimizes the use—even the killing—of animals for human purposes, so long as it aligns with divine order.

In this view, care must be taken not out of duty to animals themselves but because cruelty toward animals may lead to cruelty toward humans. This distinction anticipates later philosophers like Kant, who also argued for only indirect duties toward animals.

Key Quotes
“Accordingly intellectual creatures are ruled by God, as though He cared for them for their own sake; while other creatures are ruled as being directed to rational creatures.”
Thomas Aquinas, Summa Contra Gentiles, II.3.c112
“Hereby is refuted the error of those who said it is sinful for a man to kill dumb animals: for by divine providence they are intended for man’s use in the natural order. Hence it is no wrong for man to make use of them, either by killing or in any other way whatever.”
-Thomas Aquinas, Summa Contra Gentiles, II.3.c112


A Religious-Ontological Anthropocentrism
Aquinas gives us one of the clearest formulations of the Great Chain of Being: a hierarchy with God and angels above, humans in the middle, and the rest of nature below. This worldview has been deeply influential in Western thought and continues to echo in how we justify human use of natural resources today.

At a time when biodiversity loss and climate change threaten ecosystems worldwide, Aquinas’s vision raises pressing ethical questions. Should animals and non-human nature continue to be seen primarily as instruments for human flourishing? Or must we move toward a view that grants them intrinsic value?

Key Terms for this Lesson
Anthropocentrism: The view that human beings are the central concern and that other beings exist primarily for human ends.

Providence (Aquinas): Divine governance in which rational creatures are ends in themselves, while non-rational creatures are ordered to human benefit.

Instrumental Value: The value something has as a means to another’s end (e.g., animals used as tools for human sustenance).

Intrinsic Value: Value something has in itself, independent of its usefulness to humans.

Great Chain of Being: A hierarchical view of existence, placing humans between divine beings above and nature below.

Indirect Duties (Aquinas & later Kant): Duties regarding animals not because they are owed to animals, but because of their impact on human morality.

Discussion Questions:
As you read the text, consider the following questions...

If Aquinas is correct that animals exist for human use, does this justify unlimited exploitation? Where, if anywhere, should limits be placed?

How might Aquinas’s framework respond to contemporary evidence of biodiversity loss, species extinction, and ecosystem collapse?

What are the strengths and weaknesses of the Great Chain of Being as a way to think about moral status?

Should environmental ethics continue to be built on an anthropocentric framework, or must it move beyond Aquinas’s vision?