Tenses of English
What is a Tense?
As pointed out by Klein (1995: 141), 2500 years of research have not led to any precise or universally acknowledged definition of the category 'tense'. However, there is a widespread understanding of what 'tense' basically means. Such an 'understood' definition is for instance given in the International Encyclopedia of Linguistics (Bybee 1992: 223f.):
Tense refers to the grammatical expression of the time of the situation described in the proposition, relative to some other time. This other time may be the moment of speech, e. g. the past and future designate time before and after the moment of speech, respectively [...]. Tense is expressed by inflections, by particles, or by auxiliaries in construction with the verb [...].
Different Approaches
How many tenses are there in English? This is a simple question, to which, however, almost every linguist gives a different answer. According to Bublitz (1995: 135), these “dissenting views are reflected by the fact that linguists have yet to agree on the number of tenses [...] in English, which vary according to whether formal or semantic criteria or a combination of both are recognized. In particular, the present perfect, the past perfect and the future perfect defy easy categorization.” Linguists' different views on the number of English tenses can be grouped into four different approaches (cf. König 1995).