Relations of identity are realized in context where close or synonymous units referring to the same object, or phenomenon are used. Here we refer simile and two kinds of synonyms – specifying and substituting ones.
Simile (Latin: simile - similar) is a partial identification of two objects belonging to different spheres or bringing together some of their qualities. The objects compared are not identical, though they have some resemblance, some common features. Emphasizing their partial identity gives new characteristics to the referent.
Simile is a structure consisting of two components: the subject of comparison, and the object of comparison which are united by formal markers: as, as … as, like, as though, as if, such as etc., e.g. Unhappiness was like a hungry animal waiting beside the track for any victim /G.Greene/.
If formal markers are missing but the relations between the two objects are those of similarity and identity, we have implied simile. In such similes notional or seminotional words (verbs, nouns etc.) substitute formal markers (Cf: to resemble, to remind, to seem, resemblance etc.: e.g. H.G.Wells reminded her of the nice paddies in her native California (A.Huxley).
We should distinguish simile which is stylistically charged from logical comparison which is not. The latter deals with the notions belonging to the same sphere and it states the degree of their similarity and difference. In case of comparison, all qualities of the two objects are taken into consideration, but only one is brought to the foreground, e.g. He was a big man, as big as Simon, but with sandy hair and blue eyes (D.G-arett).
Both simile and metaphor are based on comparison. Metaphor is often called a compressed simile which differs from simile proper structurally. However, the difference between the two is not only structural but semantic as well. Simile and metaphor are different in their linguistic nature:
1) metaphor aims at identifying the objects; simile aims at finding some point of resemblance by keeping the objects apart;
2) metaphor only implies the feature which serves as the ground for comparison, simile, more often than not, indicates this feature, so it is semantically more definite.
Synonyms-substitutes (substituting synonyms) are words used to denote objects or action, supplementing new additional details, which helps to avoid monotonous repetitions, e.g. But he had no words to express his feelings and to relieve them would utter an obscene jest; it was as though his emotion was so violent that he needed vulgarity to break the tension. Mackintosh observed this sentiment with an icy disdain /W.S.Maugham/.
Substituting synonyms are characterized by contextual similarity giving rise to emotive-evaluative meaning. That is why some synonyms can be treated as such only in context. Synonyms-substitutes are widely used in publicist style. They are also regarded as situational synonyms.
Synonyms-specifiers (specifying synonyms) are used as a chain of words which express similar meanings. Such synonyms are used for a better and more detailed description of an object or person, when every other synonym adds new information about it. There are two ways of using specifying synonyms: 1) as paired synonyms, and 2) as synonymic variations, e.g. …the intent of which perjury being to rob a poor native widow and her helpless family of a plantation-patch, their only stay and support in their bereavement and desolation /M.Twain/.
These synonyms specify the utterance, adding some new information. Though the given synonyms are very close in their meaning, they are different in stylistic colouring. Synonymic variations specify the utterance, intensifying its emotional value. Such synonyms are widely used in fiction and the publicistic style. In scientific prose and official style, their usage is limited.