We should be able to accept a dog as having dignity without having to pretend that the animal is human. A dog is different from a human, but, like humans, he is a conscious being who deserves respect. At first, this seems to make sense. Humans drive cars, use computers and watch television, while animals do not. However, if there is some clear distinction between humans and other animals, this distinction must cover all humans.
Some humans exist which have no technology beyond simple shelters and weapons.
Yet they are indisputably human. A group of humans born on a strange planet, with no knowledge of human technology, would grow up to live much as chimpanzees do today. However, these creatures would still be human. Moreover, the sophistication of our technology hides the fact that the use of it often requires very little intelligence. A chimpanzee can use a VCR, although, like most humans, he or she cannot set it to record a television programme.