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Tense and Aspect

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					Introduction to Semantics • 9.1.2006


Tense and Aspect
1.     Past, Present, Future

(1)    John loved Mary.
(2)    John loves Mary.
(3)    John will love Mary.

The grammar of English requires that the speaker makes it explicit, in each sentence, whether
the stated fact or event is reported for some time before now, at now, or in the future.

Last week’s strategy was to predicate all informations about time over the event which is
introduced by the verb of the sentence. At this point, we will want to make this a bit more
precise: It is the main verb in the sentence which introduces an event. Auxiliaries (like “will”
in (3)) do not introduce further new events. Neither do they predicate transparently over
events. (E.g. the verb will in 3 no longer expresses desiredness of anything. It is purely
temporal.) Auxilaries as well as derived forms of the main verb in concert express tense /
aspect.

(4)    Surface form of verb (incl. auxiliaries) = Verb stem + TENSE/ASPECT
       will be sleeping = SLEEP + (Future+Progressive)

While verbal stem and tense are sometimes morphologically merged into one form, we will
always treat them as semantically independent parts of the sentence.

(5)    Slept = SLEEP + Simple Past

Sentences like (1)-(3) are in fact indexical. Their literal content contains an open parameter
which can only be specificed when the sentence is uttered: Tense refers to the time of
utterance. A sentence like Lucy is hungry states that Lucy is hungry at the time the sentence is
uttered. This can be explicated by looking at the truth conditions of the sentence.

We experience time as an ordered line of time points. The order of time points will be
expressed by the “smaller than” symbol <. t1<t2 states that t1 was before t2. We will generalize
this use to events: e1<e2 holds true exactly if the time of e1 lies before the time of e2. t<e states
that some time t lies before the time of event e. The equality AT(e,t) states that the time of e
roughly is at time t. (This will be refined below.)

The universal human perception of time is reflected in the English tense system. Each
utterance specifies a time of speaking S. Tense tells the hearer how an event is located relative
to S.

(6)    Past: e<S
       Present: AT(e,S)
       Future: S<e

This is our first, and simplest theory of what tense in English does.
(Remark: The first truth conditional implementations of this simple idea look much less
simple than the conditions here. The implicit coding of tense was felt to require an implicit
semantic treatment which did not make mention of the time paramenter, or events, explicitly.
Likewise the indexical nature of the now seemed to support a treatment beyond the simple
clauses in (6).)


2.     Why matters are not simple: The progressive

What about another example.

(7)    Mary kiss + Tense John
(8)    Mary kissed John.
(9)    #Mary kisses John.
(10)   Mary will kiss John.

What is wrong with (9)? Which will lead us to consider the progressive (aspect), the past and
future perfect (aspect), a side remark on the (thorny) present perfect and the notion of aspect
in general.

Discussion 1: What is the difference between the a. and b. sentences (in terms of content)?

(11)   a. Mary was reading “Old Firehand”
       b. Mary read “Old Firehand”.
(12)   a. Mary was crossing the road when she discovered Miss Marple.
       b. When she discovered Miss Marple, Mary crossed the road.
       (c. plus variants)
(13)   Mary was crossing the road when she was hit by a truck.
(14)   a. Mary is intelligent.
       b. _Mary is being intelligent.
(15)   a. Mary won the race.
       b. Mary was winning the race, when …

Result: a. perspective
       b. about statives
       c. about punctual events

Problem: What kind of fish is a perspective? What is the difference between Jill sang a song
and Jill was singing a song in terms of truth conditions? Is there any?


3.     Why matters need not be hopeless: Past perfect

A second kind of aspect helped to clarify the nature of perspectivisation (Reichenbach, 1947.
Logic and Language).

(16)   Ron patched up his wand with some borrowed Spellotape.
(17)   Ron had patched up his wand with some borrowed Spellotape.

Difference? (17) seems to refer to a salient time point in the narrative which lies before the
patching up with Spell-o-tape. Usually, such time points are explicated in the narration:
(18)   They went down to lunch where Ron’s mood was not improved by Hermione’s
       showing them the handful of perfect coat buttons she had produced in
       Transfiguration.

If we call the salient time point R (reference point), the content of (18) can be visualized as
follows:

(19)   ————— E3 ———————— E1 ———— E2=R ——————>
           H produces   Ha+R go       H shows
           coat buttons down to lunch her coat buttons

Similar intuitions arise for the future perfect:

(20)   a. When Harry will arrive at Hogward’s, Ron will have prepared tea.
       b. When Harry will arrive at Hogward’s, Ron will prepare tea.

(No exactly similar intuitions arise for the present perfect. Comments … )

This led Reichenbach, and many researchers in the following, to assume that natural language
sentences refer to three time intervals:
       S = speech time, time of utterance
       R = reference time: time point or interval which is of current interest in the narration
       E = event (/ time of event)

With a third time parameter R available, we can make a new attempt at the simple/progressive
distinction. Note that the times we talk about are often not really points in time. The exact
sciences tell us that all perceivable time is really extended time intervals. But even
perceptually, we talk about events which, as we are aware, are longer than just a fraction of a
second.
The first step then is to assume that times t can be points in time or extended intervals in time.
This observation includes event times (E) and reference times R. Speech time, however,
seems to function perceptually like a time point. We will presently see data which support this
latter claim. In terms of notation, we adopt the subset notation to express that one time
point/intervall is included in another one: t1  t2 states that the time t1 is included in t2. While
the “earlier than” relation < is no longer a total ordering on intervals, it can receive a natural
extension if we assume that an interval I1 is before an interval I2 if (and only if) I1 ends when,
or before I2 starts. Our earlier tentative “at” relation will hence be refined as inclusion of one
interval in another and identity of times, respectively (a third relation which sometimes plays
a role, possibly, is temporal overlap).

With this more refined notion of time in mind, we can now propose the following, more
elaborate tense/aspect system for English

(21)   Past Perfect: E<R, R<S
       Simple Past: R<S, E  R
       Past Progressive: R<S, R  E
       Simple Present: R=S, E  R
       Present Progressive: R=S, R  E
       Simple Future: S<R, E  R
       Future Perfect: S<R, E<R
4.       What is the nature of R?

While the system in (21) captures some intuitions about the use of tenses and aspects in
English, the nature of R is still a mystery. Is it just some point in time? In that case, the
distinction between simple and progressive tense would be vacuous.

Tense and aspect are anaphoric categories. These grammatical categories do not primarily
serve to locate isolated events before now, at now or after now. The primary gain seems to be
that the speaker can give the hearer clues how different events relate to each other in a
narrative. As a rule of thumb, we can say:

(22)     The reference time R is usually given by an event that was introduced in the preceding
         sentence, or by an event in a when-clause, or some other explicit temporal information
         in the narrative context.
        The progressive aspect contributes that the new event is around R and that the same
         time R remains the salient time perspective.
        The simple aspect in narrative texts contributes that R is at the end of the last salient
         event, and that the new event occurs in R.
        The (future and past) perfect states that the current event was before R. (Optional:
         Discussion of past perfect progressive.)

Examples:

(23)     “Oh, look,” said Flint. “A field invasion.”
         Ron and Hermione were crossing the grass to see what was going on.

(24)     ————————— E1= R ———————————>
                               [..............]E2
         E1: Flint’s utterance
         E2: Ron+Hermione cross the grass

(25)     “Oh, look,” said Flint. “A field invasion.”
         Ron and Hermione crossed the grass to see what was going on.

Example: Progressive does not shift R further

(26)     When Harry entered the common room, everybody was busy.
         Hermione was practicing a transfiguration spell.
         Ron was training Scabbers to catch a piece of cheese.
         Percy was reading “How to remain the perfect prefect”. ( … )
         Harry sat down.

Example: Simple tense sentences suggest (in narration) that one event happened after the
other.

(27) The colored lanterns that had lit the path to the stadium had been extinguished. Dark
figures were blundering through the trees; children where crying; anxious shouts and
panicked voices were reverbrating around them in the cold night air. Harry felt himself being
pushed hither and thither by people whose faces he could not see. Then he heard Ron yell
with pain. “What happened?” said Hermione anxiously (…).
5.     Coming back to the stative/eventive distinction

Let us now turn back to the first puzzle. Why can verbs that describe something happening
not occur in the present tense simple?

(28)   a. Harry is practicing a spell.
       b. #Harry practices a spell.
(29)   a. Harry hates Malfoy.
       b. #Harry is hating Malfoy.

One conceptual difference between action verbs and stative verbs consists in the fact that
stative verbs describe facts where “not much happens”. hate, love, ability are stative
properties which obtain or do not obtain of a person or thing. Some examples:

(30)   Harry hates Malfoy (loathes, abhors).
       Ginny loves Harry (is in love with, adores, likes, favours, admires)
       Ron is red-haired, is intelligent, is strong, is poor, …
       Paris is the capital of France
       Ron can /may / must / should / will practice Quidditch.

It is therefore standardly assumed that stative verbs predicate something about time points
rather than intervals. We will leave it open whether stative verbs introduce an eventuality, a
state, or simply a time argument. For concreteness sake, I will use s for state, and assume that
states s take only a point in time.

Hence, the progressive aspect is inherently senseless for stative verbs.
       The progressive states: R  E
       statives introduce states s which only take a point in time.
       If we’d extend progressive to states, it would contribute: R  s.
       But an interval R can never be a subset of a point in time.

On the other hand, if the now is indeed a point in time,
       the simple present tense instruction s=S makes sense.

Finally, assume that the events that are introduced by action verbs are always extended in
        time. This explains that action sentences can never be reported in the simple present if
        the speech time S is indeed a time point, not an interval.

(Note that this concrete proposal is one in a number of alternative, related ways to explain the
stative-eventive distinction. A full explanation will in essence rely on the same ideas, but the
notions of reference time, and progressive, need to be refined considerably. In particular, the
present analysis is orthogonal to a strand of research which models the progressive as an
operator on verbs. A synthesis of both ways of thinking is possible but would have obscured
the central idea that aspect is an anaphoric category. I will therefore leave it at the current
analysis.)
Homework 9

(1) Offer a semantic representation for the following sentence, taking explicit care of tense
and aspect. You need not spell out the full semantic derivation, but please spell out (i) the
meaning of the tenseless VP, (ii) the semantic contribution of tense and aspect, and (iii) what
the meaning of the tensed VP (= IP) will be.

       Susan was reading a book.

(2)    When Ed will enter the bank, the cashier will be counting the money.

a. Propose an analysis for the future progressive
b. Give a semantic representation for the main clause above (bold). Describe in prose the
salient reference time R for the interpretation of the main clause in (2).

(*3) Prepare an oral discussion of the following paragraph in class (!no credits will be
assigned: this is voluntary). Which temporal reference points are established and refered to
from sentence to sentence? Which sentences seem to push temporal reference further, which
don’t?

The rest of the Gryffindor team were already in the changing room. Wood was the only
person who looked truly awake. Fred and George Weasley were sitting, puffy-eyed and
tousle-haired, next to Alicia Spinner, who seemed to be nodding off against the wall behind
her. Her fellow Chasers, Katie Bell and Angelina Johnson, were yawning side by side
opposite them.
“There you are, Harry, what kept you?” said Wood briskly. (…) Wood was holding up a
large diagram of a Quidditch field, on which were drawn many lines, arrows, and crosses in
different-colored inks. He took out his wand, tapped the board, and the arrows began to
wiggle over the diagram like caterpillars. As Wood launched into a speech about his new
tactics, Fred Weasley’s head drooped right onto Alicia Spinner’s shoulder and he began to
snore.

(J.K. Rowling. Harry Potter and the Chamber of Secrets. From Chap. 7)

				
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