"There are, in fact, people who appear to think only with the brain, or with whatever may be the specific thinking organ; while others think with all the body and all the soul, with the blood, with the marrow of the bones, with the heart, with the lungs, with the belly, with the life. And the people who think only with the brain develop into definition-mongers; they become the professionals of thought. And you know what a professional is? You know what a product of the differentiation of labour is?"
— Miguel de Unamuno - Tragic Sense of Life