Thomism and the Problem of Animal Suffering

by Dr. B. Kyle Keltz

The problem of animal suffering has been championed by atheists at least as far back as the time of Charles Darwin, and it is increasingly touted today. For example, Richard Dawkins claims,

The total amount of suffering per year in the natural world is beyond all decent contemplation. During the minute it takes me to compose this sentence, thousands of animals are being eaten alive; others are running for their lives, whimpering with fear; others are being slowly devoured from within by rasping parasites; thousands of all kinds are dying of starvation, thirst and disease. . . . The universe we observe has precisely the properties we should expect if there is, at bottom, no design, no purpose, no evil and no good, nothing but blind, pitiless indifference.1

As Dawkin’s quote suggests, The problem of animal suffering is the atheistic argument that an all-good, all-knowing, and all-powerful God would not use millions of years of animal suffering, disease, and death just to create a world for humans to live. Atheists making this argument emphasize the great amount of evidence for animal disease, death, and suffering in the natural history of the earth (and still to this day), and they conclude that the God of classical theism does not exist.

In my recently published book Thomism and the Problem of Animal Suffering, I discuss a solution to this problem in light of the philosophy of Thomas Aquinas. In this post, I am going to summarize my argument in the book. I will first discuss the nature of animal pain and suffering. Then I will consider non-human animal minds and the evidence that animals are not self-aware. Finally, I will emphasize Aquinas’ ideas on why God made a finite world governed by natural laws, making animal suffering possible. All of these related concepts will come together to form a comprehensive solution to the question of why an all-good God would allow animal suffering.

The Nature of Animal Pain

While pain and suffering seem to be terrible things, a closer examination shows that they are actually good for non-human animals. Aquinas, following Augustine, believed that evil is not a substantial thing; evil is a privation of the good. Evil is not a thing in animals and objects, but it is the absence of a good thing in animals and objects. Moreover, evil is not just the privation or absence of any good; it is the absence of a good that ought to be in an animal or object. So for example, it would be an evil for a dog to be blind, but it would not be an evil for a tree to be blind. The ability to see ought to be in a dog according to its canine nature, while the ability to see is not something that is naturally in trees.

When thinking about the nature of pain, the existence of pain in non-human animals cannot be something that is evil, according to the Thomistic view. This is because pain is an existing, physiological process in non-human animals. Pain is not the privation of a good, although it is caused by a privation of the good (e.g., a scrape or cut on the arm).

But doesn’t this implication cause problems for Aquinas’ evil-as-privation view? Most people, even most philosophers, seem to think that pain is intrinsically bad. It seems a good God wouldn’t allow His creatures to feel pain because it is so unpleasant. While this view of pain seems intuitive, it actually ignores the purpose and benefits of pain.

To no one’s surprise, the findings of contemporary science suggest that pain is crucial for the survival of humans and non-human animals. For example, clinical cases involving children born with a nervous system defect, making them feel virtually no pain, show that these children do not live very long.2 Their insensitivity to pain makes it so they suffer repeated injuries to the same areas due to fractures while moving around, joint injuries because of poor posture, and tongue injuries while eating. It has even been found that sitting for prolonged periods can cause injuries if someone does not shift in their chair.3

Yet what is surprising and not immediately intuitive about pain is that its unpleasantness is necessary to protect animals. Philosophers such as David Hume have argued that the unpleasantness of pain doesn’t seem to be essential. But pain research involving Hansen’s disease (leprosy) patients has shown that the unpleasantness of pain is necessary to protect wounds.4 Doctors in these cases tried to help patients who couldn’t feel pain in their hands and feet by strapping a light or buzzer that would alarm the patients to stress or impacts that could cause injury. It was found that the patients almost always ignored the lights and sounds, leading to repeated and sustained injuries, and it wasn’t until the doctors integrated electrical shocks in the warning devices that improvements were made. But even with the electrical shocks, the patients usually would override the system, perform their desired task, and then reengage the system. One doctor concluded that without an internal signal of unpleasant pain, the patients were “task-oriented” instead of being “self-oriented.”5

Of course, humans have free will and can decide to ignore warnings, but it isn’t hard to apply the same concept to non-human animals. Animals might not survive as long as they normally do in the wild as they might not be as repelled from harm without the unpleasant effects of pain. Even chronic pain has been found to improve the survivability of non-human animals.6

So, regarding the nature of pain, the philosophy and the scientific evidence seem to coincide. Pain is actually not intrinsically bad, as it is necessary to keep non-human animals healthy and alive. Without pain, and its unpleasant commands to avoid further injury, non-human animals would lot live long at all in this world governed by physical laws; pain is good in that it ought to be in non-human animals.

Non-Human Animal Minds

Since the existence of non-human animal pain is actually a good thing, it seems there should be no problem of animal suffering. However, it is still argued that non-human animal pain and suffering are bad because of their unpleasantness. If God is all-powerful, then why can’t God just make a world where animals don’t feel pain? The necessary aspect of pain doesn’t take away the fact that there are countless animals who are experiencing pain and suffering even today.

At this point, it is good to consider the nature of the animal mind. This topic constitutes the largest chapter in my book, and the details are many.7 But long story short, contemporary research in non-human animal cognition suggests that there are no non-human animals who are self-aware.

Regarding contemporary research, scientists have studied several possible indicators of self-awareness in non-human animals including metacognition, episodic memory, and the ability to perform abstract reasoning. Metacognition is the ability to think about one’s own thoughts; episodic memory is the ability to remember past events or imagine future events from a subjective, personal perspective; and abstract reasoning is distinct from instinctual, associative reasoning, which doesn’t involve the knowledge of abstract, universal, and immaterial concepts.

While some non-human animals show promise and possibly perform actions explained by metacognition (e.g., capuchin monkeys8), episodic memory (e.g., scrub jays9), and abstract reasoning (e.g., great apes10), ultimately, there is no evidence that suggests these actions are solely explainable through self-awareness. In each case, it is possible (and likely) that these non-human animal actions are explainable through lower-order processes. Actions suggesting metacognition are thought to be explainable through associate, non-rational learning in which non-human animals simply associate rewards and punishments based on memories instead of reflecting internally. Likewise, actions suggesting episodic memory in non-human animals are thought to be explainable through associate learning based on semantic (non-personal) memories instead of episodic (personal) memories. While studies into the possibility of self-awareness in non-human animals have shown that some animals come close (e.g., higher apes, elephants, dolphins), the majority of non-human animals are not even considered to possess self-awareness. Accordingly, while a few researchers have suggested it is possible some non-human animals are self-aware, the overwhelming consensus among researchers is that non-human animals are not self-aware.

All of this scientific evidence supports the classical Aristotelian-Thomistic view that humans are unique on the earth in that only humans are capable of abstract rationality because only humans have rational souls that are capable of abstracting immaterial forms from material objects. Aquinas believed that in the process of knowing (when the mind abstracts a form from matter), a human is able to judge that he or she exists as a knowing being. In other words, the action of knowing makes it possible for a being to know that he or she knows. And in knowing that one knows, a diachronic sense of self develops over time as the knower judges that he or she has existed throughout the entire process.

Moreover, the rational soul is thought to be the principle making it possible for humans to have free will. According to Aristotelian-Thomistic metaphysics, only something immaterial can take in the form of something else without substantially changing into the new form taken. Thus, there must be something immaterial about humans because in the process of knowing, they abstract and store the forms of the things they know. This means that the rational powers (intellects and wills) of humans are immaterial and are not affected by the physical laws of nature. So, while human choices are affected by biological, psychological, sociological, and other factors, ultimately human choices are not completely determined.

What all this means for the problem of animal suffering is that non-human animal suffering is not morally significant. It is not wrong for God to allow animal suffering because there is no person in the non-human animal kingdom who is experiencing suffering. This might sound strange, and to be clear, I am not denying that non-human animals suffer. I am only denying that non-human animals experience suffering as persons (i.e., self-aware beings with a will and intellect). In other words, there is no non-human animal who knows it is feeling pain (metacognition), remembers or thinks about itself as having personally experienced pain (episodic memory), or has concluded rationally that pain is bad and should be avoided (abstract reasoning). While non-human animals are conscious of pain and suffering, they are not aware of their pain and suffering, and it is not wrong for God to allow this suffering because as I noted earlier, there is no person in the non-human animal kingdom who is suffering and/or willing to not suffer.11

Why God Created a Finite World with Animal Pain

A question might still remain: Why would God create a world in which pain is necessary in the first place? This is a question that is answered mainly through the thought of Aquinas. Following thinkers like Pseudo-Dionysius, Aquinas argued that the only reason God would want to create is to communicate or spread His goodness.

Basically, Aquinas argues that since God is completely perfect, there is nothing God could ever want or need. Yet since God is infinitely loving, and love is not something that people want to keep to themselves, it follows that God would be inclined to create a world so He could share His goodness and love. Thus, God’s purpose for creating is to communicate His goodness to rational beings who are able to know His goodness and share His love.

But there is a metaphysical reality that God must work around. The problem is that God is infinite, self-sustaining, and immaterial, but anything He can create will be finite and contingent. So, since God can’t make something infinitely perfect (because this would be to create Himself, which is impossible) to communicate His goodness, He is left with creating a finite, contingent world containing immaterial and physical beings and things.

Aquinas thought that God must create a hierarchy of beings that points metaphysically upwards to God, and God must order the universe with physical and moral laws. For example, in creating an abundance of elements in a vast universe, God is showing numerous beautiful ways in which things can exist and displaying His power to create such a universe. In creating a hierarchy of living beings, including vegetative (plants), sensitive (non-human animals), and rational (humans) beings, God is demonstrating that created beings can possess various levels of perfection, pointing metaphysically upwards to God’s infinite perfection. Any finite world God will create must be governed by a physical law because without physical laws, His hierarchy of beings would cease to exist. Physical laws order the universe to God’s purpose of communicating His goodness. Likewise, God must promulgate a moral law to humans because they cannot be ordered to His goodness solely through physical laws because of their rational souls, which include the ability to make freely willed decisions.

Basically, because of the metaphysical reality of God’s infinite, self-sustaining perfection and the contingent, limited nature of anything He will create, any world God will create will be finite and will have a limited amount of resources; any world He will create will be governed by physical laws and include a hierarchy of beings including vegetative, sensitive, and rational beings. This means that any world God could create will be a world that will include animals who will require the ability to feel pain in order to survive.


One of the most interesting things to me in performing this study on the problem of animal suffering was how much the medieval philosophy of Thomas Aquinas lines up with findings from contemporary science. There technically is no problem of animal suffering because animal pain and suffering is not intrinsically bad, but necessary for non-human animal flourishing. Moreover, non-human animal suffering is not something morally significant for God to allow because there are no persons in the non-human animal kingdom. Even if an animal were found to be rational, this would mean such an animal would technically be a human (i.e., a rational animal) and should not be considered a part of the problem of animal suffering, which solely considers non-human animals. While atheists often argue that the world we see looks like the product of natural, blind processes, only classical Christian theism predicts that any world that exists will be a world governed by both physical and moral laws and will include rational beings capable of knowing and loving.

While many aspects of the problem of animal suffering seem intuitive and sound at first, upon further investigation, the problem falls apart. Pain feels bad, but it is not intrinsically bad because it needs to be unpleasant for animals to survive. It is bad for humans to experience pain because this is against their will, but non-human animals cannot will to be free from pain nor are they able to be aware of their pain. The only thing that is infinitely perfect is God, so any world He will create to communicate His goodness will be finite and will entail the possibility of non-human animal pain and suffering.

As a summary, this blog post was not able to cover all the concepts in and many of the objections to the Thomistic solution to the problem of animal suffering. So, if you are interested in the problem of animal suffering and would like to dive deeper into the problem’s history and how it can be answered using Thomistic philosophy and evidence from science, I recommend finding a copy of my book Thomism and the Problem of Animal Suffering. The book is available for sell at,, and Links to purchase the book and information on other research I have done can also be found on my academic website:

1.     Richard Dawkins, River out of Eden: A Darwinian View of Life (New York: Basic Books, 1995), 131–133.

2.     Serge Marchand, The Phenomenon of Pain (Seattle: IASP, 2012), 8.

3.     Marchand, The Phenomenon of Pain, 8.

4.     See Philip Yancey and Paul Brand, The Gift of Pain: Why We Hurt and What We Can Do about It (Grand Rapids: Zondervan, 1997), 192–196.

5.     Yancey and Brand, The Gift of Pain, 195.

6.     Robyn J. Crook, et al, “Nociceptive Sensitization Reduces Predation Risk,” Current Biology 24 (2014), 1121–1125.

7.     See chapter 3, “The Nature of the Animal Soul,” in Thomism and the Problem of Animal Suffering.

8.     For example, see Fujita, “Metamemory in Tufted Capuchin Monkeys,” 575–585.

9.     For example, see Nicola S. Clayton and Anthony Dickinson, “Episodic-Like Memory During Cache Recovery by Scrub Jays,” Nature 395 (1998), 272–274.

10.  For example, see Josep Call, “Inferences by Exclusion in the Great Apes: The Effect of Age and Species,” Animal Cognition 9 (2006), 393–403.

11.  See the end of chapter 3, “The Nature of the Animal Soul,” for a full explanation of the distinction between awareness and consciousness.

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