Georges Canguilhem and Oliver Sacks converge on a number of aspects in relation to the questions of health and illness. Both criticized a naturalist and objectifying perspective, Canguilhem through the creation of the concept of vital norm, Sacks through a description of patients suffering from neurological disturbances. Both agree that illness is not an antinatural or absurd reality, but rather a way of living, a form of physiological balance. Their views on health, however, diverge starkly and are almost antithetical. Canguilhem admits being deeply influenced by Nietzsche: health is great health, it is the capacity to overcome illnesses and trials. This leads to a dualism that pits heroes of great health against the weaker and more fragile lives of all the others. Sacks opposed such dualism when he shows that illness is also an experience that opens new possibilities for us. Placing these two authors in a dialogue may help us problematize some of the essential issues that are at stake with regard to questions of health and illness.