(I love dogs as well, but dogs are pack animals that require exercise and attention to be physically and psychologically healthy, and I often have no time for either.)
The fact that the solitary, self-centered cat can be transformed by love into a creature capable of something more offers the despondent pet owner some hope of a reunion with their lost cat. C.S. Lewis was of the opinion that certain pets could achieve immortality in the same way we humans do: by being loved. Just as God's love of human beings transmitted through the Person of Christ is the sole means for the transformation of sinful human nature (and thus of achieving immortality), so too, speculated Lewis, could God's love as transmitted through the owner of a cat or dog (etc.) serve to transform the animal loved, changing its innate nature (i.e. its "catness" or "dogness") into something higher than mere "cat" or "dog", creating a new creature capable of some form of eternal life.
Lewis wrote about the possibility of animals being in Heaven several times. In a summer 2003 essay entitled “Animals and the Kingdom of Heaven”, Catholic writer Sean Connolly explains that
...in Lewis’ vision of heaven, the pets I had as a child - and indeed those I have now or may come to have later - may well be caught up in my experience of the heavenly realm when I die. The best expression of this idea is found in Lewis’ theological fantasy, The Great Divorce. Here he describes a woman in heaven surrounded by a train of young children, angels, and - significantly - birds and beasts. The following dialogue makes explanation:Human nature is flawed by original sin; left to ourselves, our natural end is the eternal death of Hell. The atoning love of Cheist for us transforms our broken nature into the perfect, immortal nature of the saints. In like manner, just as God transforms human nature by His love for us, enabling us to live forever, might not the limitless power of that divine love overflow through us into the creatures that we love, enabling them to somehow exist in the New Heavens and New Earth that await all those touched by the love of Christ?“What are all these animals? A cat - two cats - dozens of cats. And all those dogs ... why, I can’t count them. And the birds. And the horses.”“They are her beasts.”
“Did she keep a sort of zoo? I mean, this is a bit too much.”
“Every beast and bird that came near her had its place in her love. In her they became themselves. And now the abundance of life she has in Christ from the Father flows over into them.”
Remember, we know that there will be cats in heaven; Scripture specifically tells us that the lion will lie down with the lamb. If lions will be there, why not your cat?
In any case, that was Lewis' opinion. Your duty is to thank the Lord for the years of companionship your lost pet gave you, and to adopt another pet — preferably one in need! — that you can love and be loved by. Your local shelter is full of such animals, waiting patiently for your call.
Again, my sympathies.
Our two latest cats were rescued feral kitties. We considered purebred cats, but ultimately our hearts led us toward the homeless needy kitties - once again. They always seem so grateful for their place in our homes and in our hearts.
My theory is that anything capable of love must have a soul. Cats are certainly capable of love; therefore, their soul lives on after they pass. I hope to be reunited with my pets in heaven.