The modality of a statement differs from tense and aspect in that it does not refer directly to any characteristic of the event, but the status of the proposition [in which that event is mentioned]'' (Palmer, 2001). The word ''event'' is used to describe any occurrence, whether dynamic, static, physical, or conceptual. Among grammatical moods, there exist the Realis and the Irrealis. These tend to refer to actualised or conceptual situations respectively (Mithun, 1999). For example, statement A below would be categorised as Realis, since it is ''actualised''. Statement B must be identified as Irrealis, since it refers to a theoretical situation.
Statement A did not refer to one cheetah specifically, but referred generally to all things which are of the kind ''cheetah''. In doing so it expresses a generalisation, and so can be further categorised as being a statement in the generic mood. Very simply (Greenberg, 2003), ''generic sentences, in all languages, express generalisations.'' The phenomenon of genericity manifests itself in a number of ways, and this essay will seek to outline how it occurs in the English language. Using the guidelines that will be put forward, for identification of genericity, the essay will then analyse a number of sentences and comment on their permissibility as generic statements.
2.2 Two Varieties of Generic Statement
Krifka et. al., featured in the first chapter of Carlson and Pelletier (1995), are referenced in a number of other publications (e.g. Greenberg, 2003) as providing a full and complete review of the syntactic constructions that can be used to construct generic sentences. I will therefore take their work to be definitive, and outline the general principles here. First of all, it should be noted that there are two varieties of generic statement; the first is that which contains a ''noun phrase'' that refers to a kind of object, rather than a particular object, and the second is that which refers to a specific singular object and reports ''a regularity which summarises groups of particular episodes or facts.'' This can be more clearly illustrated through the use of examples. The following two phrases are, respectively, of the first and second variety described above:
C. Horses are heavy.
D. A horse is heavy.
Statement C uses the plural noun ''horses'' as a generic noun-phrase referring to all of ''horse-kind'', which immediately sets the modality of the statement. ''The horse is heavy'', were it not referring to a specific horse but referring to all horses (e.g. Farrar & Russell, 1991), would be another example of a generic noun-phrase having the same effect. Statement D is different in that its noun-phrase (''a horse'', using the indefinite article) does not govern the modality of the sentence. Consider the difference between ''a horse is walking through the front door'' (referring to a single incident involving a horse) and ''a horse is too big to fit through that door'' (which may refer to horses generally or one particular beast). ''A horse is heavy'', though it does not have a noun-phrase that necessarily represents all horses, is recognisably a sentence about one horse that can be used to characterise all other horses. The distinction in the English language is subtle, yet important. Krifka et. al. note that much of the information we gather about the world we live in can be summarised into these characterising statements. The key point is that the statement is made generic by the information therein, rather than simply the noun-phrase. Of course, it is possible to have a statement that is generic for both reasons, as below:
E. The horse is a fast runner.
''A horse is a fast runner'' would also be generic, but the definite article also indicates that we are referring to an entire genus.
3. Example Statements
Now that an outline has been drawn of what constitutes a generalisation, we will examine statements F through N. They will be analysed in order to judge whether they truly are generalisations - and whether they are permissible generally, with reference to their grammar.
F. Whales are an endangered species
G. The whale is an endangered species
H. A whale is an endangered species
Statement F uses a generic noun-phrase to produce a generalisation and is clearly a comprehensible statement. It is untrue, since ''whales'' constitute an order (the order Cetacea) and not a species 'C since a species is a group of animals that are capable of interbreeding, which is not true of all whales. Nevertheless, the statement is a falsifiable axiom and therefore has conceivable meaning. Statement G is simply a variation on statement F, using a different generic noun phrase. Statement H is structurally acceptable as a generalisation but not grammatically permissible as an equivalent to the previous two statements. It begins with the singular ''a whale'' and ends with the plural ''an endangered species'' and thus there is a disagreement about the number of whales in the sentence. The only time that a singular/plural indeterminacy would be allowable in a sentence would be in a form similar to the use of the ''singular they'', as in ''Anyone who thinks that they...'', and this would somewhat change the meaning of the statement.
I. Zebras have striped coats
J. The zebra has a striped coat
K. A zebra has a striped coat
The statements I. through J are all meaningful, well-constructed generalisations, making use of all of the syntactical devices discussed above. The first two make use of a generic noun-phrase, while statement K is a characterising statement that references one zebra but can be applied to any.
L. Liquids have no shape
M. A liquid has no shape
N. The liquid has no shape
Statement L is a generalisation that uses a generic noun-phrase while statement M is a generic characterising statement. Statement N is a generalisation, but would take a different meaning, since ''liquid'' is never truly a singular noun but rather a ''mass noun'' (ironically due to the fact that it has no shape). ''The liquid'' is not likely to be recognised a genus, but rather as a reference to a previously indicated liquid. Mass nouns have what is known as ''cumulative reference'', which means that if you add them together you end up with the same word. For example the word ''chair'' is not a mass noun and does not have cumulative reference, so we must use a plural if we talk about more than one chair. If we add one chair to another chair, so to speak, we end up with chairs. If we add some liquid some more of the same liquid, we simply end up with ''some liquid''. Any statement about a mass noun is a generalisation in English unless it makes mention of units of measurement, since all parts of it (and therefore all instances of it) are thought to be the same. The use of the definite article in this final example thus indicates, when it is taken out of context, that we are talking about a specific liquid rather than a genus referred to as ''the liquid''. If it were in a context that introduced the phrase ''the liquid'' to refer to all liquid things, which would be unusual, statement N could then take the same meaning as statements twelve and thirteen.
In summary of the statements we have explored, it is important to note that although some statements might adhere to the syntactical structure necessary to take on a certain grammatical quality, such as the generic mood, they will not necessarily be sensible. Also, a generalisation does not have to be correct in order to be meaningful, as we are aware from the philosophy of science 'C it simply has to be falsifiable. The most common method for creating generalisations with the English language is through the use of generic noun-phrases, as demonstrated. There are some nouns that are special cases however, as we noted in reference to statement fourteen above, and care must be taken to ensure that the statement is syntactically viable in these cases as there are extra rules to be observed. In most other cases however, a noun can be used in conjunction with an article as a synecdoche, to represent the whole of its kind 'C thus forming a generalisation.