All errors are not unrecoverable, you think. Full logic control. You recall from last week's logic lecture what can be done with words, Aristotle's categorical propositions in standard form. P. No errors are unrecoverable. All errors are unrecoverable.
Some errors are unrecoverable.
Some errors are not unrecoverable. You try to remember which is a contradiction, which a mere contrary. It escapes you. Unmoved mover, you think. That was Aristotle too.