The most troubling statement I've seen -- and I've seen it more than once -- goes like this: "If Fido isn't in Heaven, then I don't want to go there."
Of course, if the most appealing thing about Heaven is the prospect of meeting an animal (or, for that matter, any other mere human being) there, I'm afraid it's a safe bet that the speaker needn't worry about being there.
In one of the Diskworld books Terry Pratchett ran the numbers (Heaven as the big cube described in Revelation) and (after allowing for heavenly hosts, essential services and a vast crowd of humanity) concluded that there was room for pets.
Butch, you attacked everyone that came in the door. I still carry the scars. Had you not died I would have killed you myself. God please keep Butch away from heaven, he was the dog from Hell.
All I know is that if there are animals in heaven, my wife will be in charge of the squirrels.
Since the bible is silent on this, Lewis' speculations, a lot like Roman Catholic arguments from natural law, are interesting--and may well shed light on the issue. Lewis reasons that it is in the nature of love to love what is loved by your beloved. If you really love a woman who likes the color red for example, you too will soon become fond of red also--even if you never were before--for it reminds you of your beloved. In the same way if we love a creature especially--appreciating what the Creator put in that creature, than our Father the Creator will also have a special love for that particular creature. This means that a bear in the middle of the woods who dies a brutal death in the wilderness may well not have any eternal existance, but a beloved pet of a believer will...
Interesting speculation--if taken that way (as Lewis intended)--in any event.
This is the first genuine reformed reflection I've seen on that, and I'm glad it comes from the OPC. I agree too that no animal can commit a sin, since they never had any choice in the matter. As far as R.C. Sproul's speculation that killing a killer animal proves some sort of guilt--that's a silly argument. It's simply a practical matter that an animal that has killed is very much at risk of killing again--hence must be eliminated.
*That's a joke guys, Lewis--at least on predestination--was anything but reformed--on other issues though, coming from the Anglican church, I think he did show reformed instincts.