The problem is that this is your strawman. We have yet to nail down the problem of proton decay, which, if it proves to a verifiable significant factor, might mean that all matter in the universe will decay in the next 20-50 trillion years. Of course, scientists have proposed other alternatives, but you probably wouldn't recognize them.
ME: Answer the question of how matter could be eternal.
YOU: The problem is that this is your strawman. We have yet to nail down the problem of proton decay, which, if it proves to a verifiable significant factor, might mean that all matter in the universe will decay in the next 20-50 trillion years. Of course, scientists have proposed other alternatives, but you probably wouldn't recognize them.
What was my question? Why is matter eternal (as beavus asserts).
What was your answer? Matter may not be eternal.
Well then, if matter is not eternal, explain its origin.
Thirteen hours have elapsed and not one of you have been able to answer the question!