 The absent qualia hypothesis is the hypothesis that functional duplicates of sentient creatures are possible, duplicates that entirely lack qualia. For example, one writer (Block 1980) asks us to suppose that a billion Chinese people are each given a two-way radio with which to communicate with one another and with an artificial (brainless) body. The movements of the body are controlled by the radio signals, and the signals themselves are made in accordance with instructions the Chinese people receive from a vast display in the sky which is visible to all of them. The instructions are such that the participating Chinese people function like individual neurons, and the radio links like synapses, so that together the Chinese people duplicate the causal organization of a human brain. Whether or not this system, if it were ever actualized, would actually undergo any feelings and experiences, it seems coherent to suppose that it might not. But if this is a real metaphysical possibility, then qualia do not have functional essences.