Dominic Lynch struggles here with the question whether dogs go to heaven. While he affirms that dogs possess a spiritual nature (something I also subscribe to), he concludes dogs do not go to heaven:
About a year ago, I unexpectedly lost my 13-year-old yellow Labrador. I was heartbroken. Ruby had been part of my family since I was in grade school. She saw me grow up and go to college; I saw her age gracefully from a young puppy full of energy to an old hound who enjoyed life. Her passing was like losing a family member—because she was a family member.
But despite my sorrow, I don’t believe she’s going to heaven, canine or otherwise. Imagining a loved one (including pets) resting peacefully in the Great Beyond is a comfort to many people. But in the case of dogs—indeed, any animal—the possibility that they will join us in eternal bliss is a long shot, if not purely impossible.
He concurs with Thomas Aquinas’ conclusion that animal souls are not intellectual souls, and as non-intellectual souls they are not subsistent souls. This implies that the intellectual property human souls inherently carry makes them eternal.
This is actually something I have wrestled with. One must be careful not to be dogmatic since Scripture is silent on this issue. Unlike Dominic, some reject that dogs even have a spiritual nature - something that Wesley Smith also refuted here in Christianity Today:
We have come a long way since Descartes claimed that animals are mere automatons without the capacity for pleasure or pain. We now know the contrary is true: They experience. They suffer. They grieve. They love.
When it comes to our relationships with pets, we not only take them into our homes: We welcome them deep within our hearts. In fact, some become so attached that they yearn to be with their pets throughout eternity. C. S. Lewis speculated on the eternal fate of animals in The Problem of Pain, suggesting that at least tame animals might enter heaven through their relationship with humans, in the same way that humans do through their relationship with Christ.
Wesley also correctly cautions that there is a danger that the question of pets in heaven could distort our understanding of eternal life as described in Scripture and Christian tradition. If we are not careful, we could cross the line into a sentimentality that shrinks our eschatological expectation.
Karen Swallow points out in the same Christianity Today article that:
Yet the Bible teaches that God does save animals. For example, God brought Noah two of each kind of living creature in order to save them from the Flood. God chastised reluctant Jonah about the need to save not only the human inhabitants of Nineveh, but also its many animals. Such salvation is not, of course, quite the kind invited by the altar call. Even so, it should not be overlooked.
God not only saves animals. At times, his covenants include them. God's covenant with Noah included "every living thing of all flesh" (Gen. 6:18-19, KJV). In Hosea, God proclaimed a covenant "with the beasts of the field, the birds in the sky and the creatures that move along the ground" (2:18, niv).
.... I have put away my childish thinking about heaven. Scripture describes eternity not as an ethereal cloud-top existence, but as both spiritual and material, just as our life is now. It is a new heaven and a new earth (2 Pet. 3:13) where "creation itself will be liberated from its bondage to decay and brought into the freedom and glory of the children of God" (Rom. 8:21). As foretold in Isaiah, animals will be there. "The wolf will live with the lamb, the leopard will lie down with the goat … and a little child will lead them" (11:6). Perhaps God will honor my acts of naming the animals by bringing Gracie, Kasey, Myrtle, Peter, Oscar, and so many more there, too.
Ben Devries correctly highlights Christ's assertion that not even one sparrow is ever forgotten by Him.
Wesley's conclusion (which is also mine) is wise advice ...
So do pets have souls? Do they go to heaven? God knows. For now, "we see through a glass darkly." Instead of speculating or making strained proof-texts, let us instead give thanks to God for the great gift of joy he has given us in our pets. Let us be confident in the knowledge that whatever his plans for our animal friends, all will be perfection and light.