What is the theory of Descartes’ animal-machine?
Descartes believed that animals have no mind and their movements are reduced to a set of purely physical processes (mechanical and chemical).
According to Descartes, “Animals are not only less reason than men, they have none at all.”
This theory will be challenged by Peter Singer in particular in the Animal Liberation, that the suffering is real, the animals must have the same rights as individuals. He said the difference made by Descartes between man and animals is speciesism.