An intoxicating drink, which both slides down easily and warms as it goes, is a symbol of — and also a means to achieve — an inward transformation, in which a person takes something in to himself. Hence you find wine, from the earliest recorded history, allotted a sacred function. It is a means whereby a god or daemon enters the soul of the one who drinks it, and often the drinking occurs at a religious ceremony, with the wine explicitly identified with the divinity who is being worshipped: witness the cult of Dionysus, the Eleusian mysteries, the Athenian festivals such as the thesmophoria, the mystery cults of Diana and the Egyptian child Horus. For the anthropologist, the Christian Eucharist, in which the blood of the sacrificed lamb is drunk in the form of communion wine, is downstream from the mystery cults of antiquity, which are in turn downstream from those ceremonies that accompanied the vinifying of the grape among the great heroes who first discovered how to do it and believed, with commendable piety, that it was done by a god.

The religious use of wine and its soul-transforming effect reflect the underlying truth that it is only rational beings who can appreciate things like wine. Animals can be drunk. They can be high on drugs and fuggy with cannabis, but they cannot experience the kind of directed intoxication that we experience through wine, since relishing is something that only a rational being can exhibit, and which therefore only a rational being can do. Hence we control our intake, and are acutely aware of the danger that our rational powers, and the human relations that depend on them, can be jeopardised by the wrong kind of drinking. In the normal human case, therefore, we endeavour to remain true to ourselves in our cups, and to display nothing when under the influence that we would wish to hide when not. 

Alcohol in general, and wine in particular, has a unique social function, increasing the garrulousness, the social confidence and the goodwill of those who drink together, provided they drink in moderation. Many of the ways that we have developed of drinking socially are designed to impose a strict regime of moderation. Buying drinks by round in the pub, for example, has an important role in both permitting people to rehearse the sentiments that cause and arise from generosity (yet without bearing the full cost of them), while controlling the rate of intake and the balance between the inflow of drink and the outflow of words. This ritual parallels the ritual of the Greek symposium, and that of the circulation of wine after dinner in country houses and Oxbridge common rooms.