Though a study of the liturgy is undertaken to find the meaning of, to get behind, so to speak, the elements (the words, actions, things) of the Church's ceremonies, it may seem a little strange that we should look for a symbolical meaning of necessary a receptacle as a chalice or cup in any religious rite in which a liquid is used. But man's knowledge begins with the senses. Metaphors, sensible (corporeal) representaons or similitudes are not only natural to man but naturally pleasing to him—for which reason St Thomas says, it is fitting that pmtual things are given to us by means of metaphors drawn from corporeal things, sub metaphoris corporalium.
Man has always tended to express his religious or spiritual ideas in terms of his physical environment and his reactions to it, in terms of things that are vital and familiar to him. Though this anniiarity has perhaps clouded the modern sophisticated mind, the Principle remains fundamentally true.