Animal theology
Animals
We may find it difficult to formulate a human right of tormenting beasts in terms which would not equally imply an angelic right of tormenting men.C.S. Lewis, Vivisection
C.S. Lewis loved animals, as his earliest writings show. He felt the question of animal suffering was a significant problem for Christianity: so important that he dedicated a chapter of The Problem of Pain to it.
Lewis believed that humans were absolutely separate from animals, but he considered animals conscious - or some animals to be more conscious than others. It would be unhelpful to group apes with earthworms: "Clearly in some ways the ape and man are much more like each other than either is like the worm". There was a difference in complexity from 'lower' to 'higher' animals.
"At some point ... sentience almost certainly comes in, for the higher animals have nervous systems very like our own." (The Problem of Pain) This was by no means an accepted view. It would have been a potentially expensive one, because vivisection - damaging or fatal experiments on animals - and other exploitative uses of animals were commonplace, and acknowledging animal sentience would mean admitting that these practices were cruel.
Cruel men
Lewis condemned vivisection absolutely, and said so in a 1947 essay. He deplored the popular arguments in favour of experiments on animals, calling them "easy speeches that comfort cruel men". He pointed out that the same ideas could be used to justify experiments on humans, and explicitly drew a comparison with the Nazis.
This would be emotive language at any time, but it was shocking in context: this was 1947, two to three years after the liberation of the concentration camps.
The Christian defender ... is very apt to say that we are entitled to do anything we please to animals because they 'have no souls'. But what does this mean? If it means that animals have no consciousness, then how is this known? They certainly behave as if they had, or at least the higher animals do. I myself am inclined to think that far fewer animals than is supposed have what we should recognize as consciousness. But that is only an opinion. Unless we know on other grounds that vivisection is right we must not take the moral risk of tormenting them on a mere opinion.
On the other hand, the statement that they 'have no souls' may mean that they have no moral responsibilities and are not immortal. But the absence of 'soul' in that sense makes the infliction of pain upon them not easier but harder to justify, for it means that animals cannot deserve pain, nor profit morally by the discipline of pain, nor be recompensed by happiness in another life for suffering in this. ... 'Soullessness', in so far as it is relevant to the question at all, is an argument against vivisection.
C.S. Lewis, Vivisection
Lewis's love for animals shines through all his writings, and it made him especially concerned with finding a meaning behind animal suffering.
Nature red
Lewis's concern did not end at animal pain that was inflicted by humans. He saw the whole of nature as cruel, with animals killing and eating others to survive. His theology explained human pain by way of humanity's fallen state, but animals had committed no sin. Lewis reasoned that humanity's fall had brought animals down to a fallen state too.
In examining the problem of wild animals' pain, Lewis's thinking involved a hierarchy: from plants, the 'lowest' form of life, to animals, humans, angels and finally God. Lewis saw conflict in the world of plants, where the competition for light and nutrients caused some plants to succeed and some to die, but he didn't think this was cruel: plants are not sentient, so they don't feel pain or suffering.
The idea of animals preying on other animals presents more of a problem, at least where the prey is sentient. Lewis, along with other theologians, felt that this could not be the natural way of things and that an evil power had altered nature in order to cause more misery. (As The Screwtape Letters shows, Lewis believed in Satan.)
If it offends less, you may say that the "life-force" is corrupted, where I say that living creatures were corrupted by an evil angelic being. We mean the same thing: but I find it easier to believe in a myth of gods and demons than in one of hypostatised abstract nouns.C.S. Lewis, The Problem of Pain
In The Problem of Pain Lewis presented an imagined glimpse of un-fallen humanity, as he had previously done in the fictional settings of Out of the Silent Planet and Perelandra. He believed humans had fallen to a lower state, so that they were much more like animals. Taking this idea further, he ventured the idea that animals had fallen back to "behaviour proper to vegetables" - that the behaviour of preying on each other was something natural to plants and not to animals.
Despite these ideas, Lewis does not seem to have believed that humans should be vegetarian: indeed, he was known to poke fun at 'fashionable' vegetarians. Vegetarianism was not widespread in the 1950s, nor was the knowledge that a vegetarian diet can be healthy, so Lewis's attitude is hardly surprising.
Pet heaven
Lewis, very unusually for the time, thought that there ought to be some provision in Christianity for resurrection or heaven for animals.
Resurrection would be meaningless for some animals: "If the life of a newt is merely a succession of sensations, what should we mean by saying that God may recall to life the newt that died to-day? It would not recognise itself as the same newt". If the newt was not aware enough to be made miserable or happy by pain or pleasure, there would be no way to reward it or compensate it for its life on earth.
Domestic animals, though, obviously had something like a personality. Lewis thought that when humans tamed animals, in accordance with their God-given dominion over them, the animals became more themselves.
To Lewis the practice of taming animals, and making them more humanlike, was an obvious parallel to God's way of making believing Christians more Christlike. He suggested that domestic animals might somehow achieve immortality in the context of their masters' immortality. It is a comforting thought for anyone who has hoped to see their beloved pet in heaven, though not much use to a dog belonging to a non-Christian.
The talking animals of Narnia are a different case. They have humanlike personalities and free will of their own and seem to be responsible for their own actions.