Análisis

past tense. By contrast, if the future tense is expressed by means of auxil- iaries it is not anaphoric in this sense, and a slightly different formalization is called for.

The examples involving the interaction of future tense with condition- als, taken from Comrie [18, p. 117-121], again show that it is almost impos- sible to separate the purely temporal features of the future tense from the planning features. The default temporal interpretation of a conditional is that (a) the subordinate clause sets up the temporal reference point, and (b) the event described by the main clause is located after this reference point. This explains the distribution seen in (35). Similarly, (36-b) expresses that the ‘you’ does the shopping first, and will be paid back later. It is possi- ble to liberalize the order, as in (36-c), where, at least according to Comrie [18, p. 119]16

, the relative timing of the events is not fixed. However, the possibilities for doing so are severely restricted, as (37-a) shows. This is a particularly complicated set of data, which will be analyzed in depth in Section 5.3.1. The preceding considerations now have to be cast into for- mal definitions.

5.1. Events without frills. Consider the future tense as applied to the occurrence of events per se, abstracting from the possibility to plan. We have seen that the syntactic present tense is the preferred mode of expres- sion for this case. We have already seen that due to the anaphoric element in examples such as (38), a formalization involving integrity constraints is called for, just as we did for the simple past tense.

DEFINITION 31. (a) For all Aktionsarten except states, the future use

of the syntactic present tense is represented by an integrity constraint of the form: if the query?Happens(e, t)succeeds, then the query?Happens(e, R), R _≤

now must fail. Heree is either derived from an activity or an accomplish- ment by hierarchical planning, or the canonical event of achievement or point.

(b) If the fluentf represents a state, the future use of the present tense is de- fined by the integrity constraint that the query ?HoldsAt(f, R), R > now

must succeed.

Turning now to the perspective from which events are viewed as the result of planning, we have three modes of expression, by means ofbe going to,willand the (present) futurate progressive.

5.2. Be going toVP. This periphrastic construction is of special inter- est to us, because its evident spatial origin ties in neatly with the spatial origin of the event calculus as a formalism for path planning. It has been claimed thatbe going to VPis a prime example of a fundamental metaphoric transformation SPACE_−→TIME, but the situation is much more subtle, as has been clearly explained by Bybee, Perkins and Pagliuca [12, p. 268].

120 8. TENSE

The temporal meaning that comes to dominate the semantics of [‘be going to VP’] is already present as an inference from the spatial meaning. When one moves along a path toward a goal in space, one also moves in time. The major change that takes place is the loss of spatial meaning. Here. . . the function of ex- pressing intention comes into play. When a speaker announces that s/he is going somewhere to do something, s/he is also an- nouncing the intention to do that thing. Thus intention is part of the meaning from the beginning, and the only change nec- essary is the generalization to contexts in which an intention is expressed, but the subject is not moving spatially to fulfill that intention.

We similarly hypothesize that the mental planning apparatus was first used for path planning, and then extended to cover other domains as well. If there is indeed such a close connection between be going to VP and the event calculus, in particular the part involving theTrajectorypredicate, then the following construction naturally suggests itself. In the event calculus, the meaning of ‘go to’ can be modelled by means of a scenario linking an activity fluentf1and a parametrized fluentf2(x), which represents the path

followed driven by the action of f1. The main component of the scenario

is thus a dynamics. Since the auxiliary is ‘be going to’, the definition of the progressive has to be applied, which means that the integrity constraint must apply to the fluentf1. Combining the auxiliary with a verb, as in the

expression ‘be going to fly to Chicago’, we have to add an event type corre- sponding to ‘fly to Chicago’. The event and the fluent are ‘glued together’ by means of a scenario: the event will be the culmination of the preparatory phase f1. The scenario provides the activity fluent with the meaning ap-

propriate to the context, that is, it determines the precise activity involved. In the case of a stative verb, as in ‘be going to be CEO’, the possibility of an inchoative reading arises because the event calculus allows one to de- fine an event marking the beginning of the state, thus reducing this case to the previous one. These considerations will now be turned into a formal definition.

DEFINITION32. The future use ofbe going to VPcan apply either to a

fluentf (if the defaultAktionsartofV P is a state) or an evente(all other cases).

First consider the case whereV P is an evente(e.g. ‘fly to Chicago’); then be going to VPrequires the presence of a plan, comprising

(1) a fluentf1 representing the preparatory activity

(2) a parametrized fluentf2(x)representing the (continuously chang-

ing) result of that activity

(3) a certain stagef2(c)off2(x)which triggersevia a formula

5. FUTURE TENSE 121