Today is Monday.
If someone really thinks today is Tuesday and they say today is Tuesday, is that a lie?
It certainly isn't the truth.
But that person probably would not be declared a liar. Just mistaken.
Let's say that Trump knew about Don Jr's Russian meeting and in fact there were emails or recordings of him acknowledging this.
In other words, the truth is that Trump knew about it for sure.
Now let's say that Trump honestly forgot about this and is questioned, under oath if he knew about it. (old age, dementia, whatever)
And he states that he never knew about this meeting.
Would that be a lie? Or would he just be mistaken?
And if he is mistaken, can you extrapolate that to everything he may say and conclude that he does not lie?