# For a sentence with logical conclusion shouldn't we use past pefect?

The question is as follow :

I ___ (see) him in the park so he can't be at home

I have always though that sentence like this with logical conclusion should always use past perfect tense because there is no direct time expression and also it has a connection to present. The problem is that according to the key answer this is simple past tense. If it is correct why is it using simple past tense?

• Logical conclusions is not a test of the past perfect. I ate eggs for breakfast so I can't be hungry [now]. Sep 25, 2023 at 14:50
• The present perfect would imply that the sighting was recent, and "just" would make that explicit. "I've just seen him at the park so he can't be at home". Of course, that would imply that he lives far enough from the park that he couldn't be at home yet, even if he left the park immediately after you saw him. Sep 25, 2023 at 17:40
• I see him in the park [now] so he can't be home now. OR I'm seeing him in the park so etc. No past perfect and no simple past either. Neither of those would work here. Oct 25, 2023 at 17:12
• I think you're confused. Connection to the present usually implies present perfect. Although in this case simple past is preferred for reasons that will be explained below. Oct 26, 2023 at 10:25

We use the so-called "past perfect" only when we are choosing to refer to events from the perspective of some later time in the past (and often, we don't need to use the construction even then). In your example, there is no obvious later temporal focus, so the "had seen" construction is not expected. It could be used, and implies a later viewpoint. already established:

I went to see his wife yesterday. I had seen him in the park, so I knew he wouldn't be at home.

But I can't think of a plausible example where the final clause is in the present (he can't be at home).

I guess the way you are thinking is that, if you say that you saw someone (past tense) then they are no longer in your sight, and so logically you cannot say with certainty where they are (or are not) now.

However, "can't be" is not always used so affirmatively. We can use it to express disbelief (eg "you can't be serious?") or to eliminate just one of many possibilities when a certain answer is still not known.

A statement with absolute certainty would be:

I can see he is at the park, so he is not at home.

Saying "he can't be at home" just expresses the belief that you don't think he could be. Perhaps the time that you saw him in the park does not allow enough time for him to have returned home?

• I can see him in the park [now] so he can't be at home. OR just: I see him or am seeing him etc. They all work. Oct 25, 2023 at 17:13

Possibilities: I ___ (see) him in the park [now] so he can't be at home.

I see him etc. I am seeing him etc. I can see him etc.

Simple past and past perfect do not work here.

I saw him in the park so he couldn't have been at home. I had seen him in the park so he couldn't have been at home.

• Please also explain why simple past and past perfect don't work. Filling in the blank doesn't help the OP learn why those tenses can or cannot be used.
– gotube
Oct 25, 2023 at 19:11