There is a use in language we could compare to a natural phenomenon on Earth, namely gravitation. It can help us choose on the time frame and decide between the Perfect or Simple Aspects.
In CHAPTER 6, we began with clocks and grounds in experience. We people yet happen to speak without a clock, or to share novelty.
The Perfect Aspect may be our choice to tell about effects of something, or to highlight regards.
5. He has met Jim’s little cousin.
Carl can tell the kid is very curious about the world; the highlight is on the personal impression that holds also in the present time.
5a. He met Jim’s little cousin last summer.
It was when Carl last went to visit Jim; the phrase last summer provides the ground in time and makes the linguistic gravitation work: we close the frame.
Our closing the frame does not mean we have to divide the PRESENT from the PAST or FUTURE. We could say,
5b. He says (that) he met Jim’s little cousin last summer.
The Perfect Aspect has an open time frame. It always tells about a span.
We could not say,
5c. *He has met Jim’s little cousin last summer.
(In linguistics, an asterisk usually marks an incorrect expression.)
To speak about the present and the past or future, we mind the frame and verb. Not only Simple, also Progressive tenses have their frames closed. If we neglect the time frame, our syntax may be broken.
5d. *He (says that he) has met Jim’s little cousin last summer.
The open frame may suggest effects, highlights, as well as prospects.
6. He has written ten books.
(He is likely to write more; his writing belongs with the PRESENT.)
6a. He wrote ten books.
(Maybe he is not going to write any more; his writing belongs with a closed time frame in the PAST.)
We yet always mind our gravity.
6b. He wrote the book last year.
(We do not consider, if his writing belongs with the PRESENT or PAST. We have the notional ground and this makes our linguistic gravitation work.)
Classic grammar books might advise the Present Perfect in response to 6b:
6c. I have/haven’t seen the book.
The open frame would emphasize the time span. In everyday American we are likely to get the Simple Aspect with some cognitive ground:
6d. I never read / saw the book, and I was at the fair…
6e. I read it that summer.
Feel welcome to further language journey.
6.2. ASPECT COGNITIVE VARIABLE AND TIME FRAME