[Essay on pain]

The classical conception of pain, considering it as pertaining to a specific sensation, called pain or nociceptive sensation, ie capable of differentiating between all informations those which are detrimental to the organism, is unsatisfactory. The organization of somesthetic pathways allows to say that this pain sensation, associated with temperature sensation, stems from the most archaic nervous sensation: that of the most primitive organisms, for whom contact provokes a flight reaction. This leads to consider the presence of a "contact" sensation, thermic as well as mechanical, "existential" so to speak, far different from touch sensation which is a discriminatory sensation. Pain appears at one end of a chain, the other end corresponding to cutaneous contacts. These latter contacts are pleasurable or very pleasurable, as typified by sexual contacts. Beyond pain, the archaic nervous function is the origin of a whole defense and protection system for the organism. Pain constitutes the subjective alarm mechanism, triggered off in case of lesion or break of the primitive envelope or of its by-products. This existential sensation, with pain as its most blatant manifestation, has held a central place in the course of evolution: our organism could in this way become aware of its own existence. For all of us it plays an important role in the organization and structuring of our personality.