Tom was a philosopher who specialized in animal rights theory. He was professor emeritus of philosophy at North Carolina State University, where he taught from 1967 until his retirement in 2001. Tom was the author of numerous books on the philosophy of animal rights, including The Case for Animal Rights, one of a handful of studies that have significantly influenced the modern animal rights movement. In these books he argued that non-human animals are what he called the "subjects-of-a-life" (approximately sentient - capable of experience), just as humans are, and that, if we want to ascribe value to all human beings regardless of their ability to be rational agents, then to be consistent, we must similarly ascribe it to non-humans.
From 1985, he served with his wife Nancy as co-founder and co-president of the Culture and Animals Foundation, a nonprofit organization "committed to fostering the growth of intellectual and artistic endeavors united by a positive concern for animals."
Tom was vegan and seems to have had a naturalistic worldview. While relying on a secular perspective he also worked to encourage those with religious worldviews to take the rights of sentient animals seriously, as in this piece.