I don't see a contradiction, do you?
If an event is present, then it is not past.
An event that is present is immediately past.
That's contradictory...at least it seems that way to me.
Perhaps you could clarify?
To know, to be certain, is to be able to show truth or falsity. It is not possible to show the truth of an event before its happening. What we show about a proposition when we know it, is its truth.
What do you mean by "shown"? Presently empirically observed? Logically or mathematically demonstrated? ...then it follows that I can't know about anything other than what I presently observe or have demonstrated to me.
Future tense statements are believed true or false but, they cannot be known true or false.
Why? Are you saying I can't know that Obama will be president of the USA tomorrow? If "Obama will still be president of the USA tomorrow" is true, and if I justifiably believe it is true (for which I am, in fact, justified), then I can know about a future event. It is certainly possible that Obama is killed by an assassin before he wakes up in the morning, sure. But I certainly don't require demonstrative certainty to know that he will still be president tomorrow, if this is, in fact, true and I am justified in believing that it is true. I don't have to be certain that a proposition about some event is true in order to know the proposition about that event is true. But this seems to be exactly what you are implying: that knowledge requires demonstrative or empirical certainty...
Certainty is truth with respect to the method of decision that provides it.
I don't understand what that means.
"P" is true, if and only if P.
Certainty has to do with some kind of notion of infallibility, or subjective degree of belief (level of conviction), like Cartesian indubitability.
It seems obvious to me I can still know that P even though I am not certain that P. It also seems obvious to me we are not really certain about anything, either. And if knowledge requires certainty, then I don't know anything at all.
"justified true belief" needs clarification.
There is a lot of stuff about that notion, and it is still widely discussed.
But it does have a core significance for epistemologists. Suffice it to say, I am justified in believing that P if I am within my "epistemic rights" to believe that P. So I know that P if and only if I am justified in believing P and P is true.
Past tense propositions are true when they are shown to be the case.
So if past-tense propositions are not "shown" to be the case, then they are false
? That's not right. Are you proposing some kind of epistemic idealism, that what exists, or is true, consists only in what I can immediately perceive in the present time, or have demonstrated to me in the present time?
The record of their truth is current but the past is not current.
Yes. But that doesn't mean past-tense propositions are false,
or not known
to be true.