scorp16 wrote:
I'm confused why we can't go for Past Perfect Tense Usage for Conditional Statements (If X, Then Y).
I thought both options B & E adhere to this.
[color=#00aeef]If I had no doubt, I would not have posted this comment
The rules for if-then construction are as follows:
CASE I - Unlikely event
in the future: IF hypothetical subjunctive, THEN conditional (would).
If I went to school ( tomorrow), I would be sick... The sentence implies that I am unlikely to go to school tomorrow. But if I went (tomorrow), I would be sick.
If I had doubt, I would post this comment.....The sentence implies that I am unlikely to have a doubt (in future). But if I had (in future), I would be sick. Here "had" is NOT SIMPLE PAST, but hypothetical subjunctive that is unlikely to happen in future.
If I had no doubt, I would not post this comment.... the sentence implies that you are unlikely not to have a doubt ( you are likely to have a doubt in future).
CASE II - Past event that never happened in the past: IF past perfect, THEN conditional perfect (would have)
(CASE I CANNOT be used, if a past event is described that never happened.)
If I had gone to school yesterday, I would have been sick.
If I had had doubt, I would have posted this comment. (
had had is past perfect of had)
If I had had no doubt, I would not have posted this comment.
Therefore, your sentence ( "If I had no doubt, I would not have posted this comment") mixes up a hypothetical subjunctive in the IF clause with a conditional perfect in the THEN clause, and is therefore incorrect . You must use a past perfect, neither simple past, nor hypothetical subjunctive with a conditional perfect, when you are describing a past event that did not happen.