Is the last word in “The past is ____.” ‘past’ or ‘passed’?

Question

Which of the following is correct?

• “The past is past.”
• “The past is passed.”

Both seem plausible to me.

Answer 1

It's passed (passed by us, over, finished). It's entirely correct, although rather archaic to conjugate pass with be.

The past is passed, the future is now is apparently a quote from Joe Dirt, but it's rather like Shakespeare's Tempest:

Whereof what's past is prologue; what to come, In yours and my discharge.

Answer 2

Could be past.

The past is past, the future unformed. — William Gibson (from All Tomorrow's Parties)‎