# 17

Recently the Large Hadron Collider was damaged by a mechanical failure.  This requires the collider to be warmed up, repaired, and then cooled down again, so we're looking at a two-month delay.

Inevitably, many commenters said, "Anthropic principle!  If the LHC had worked, it would have produced a black hole or strangelet or vacuum failure, and we wouldn't be here!"

This remark may be somewhat premature, since I don't think we're yet at the point in time when the LHC would have started producing collisions if not for this malfunction.  However, a few weeks(?) from now, the "Anthropic!" hypothesis will start to make sense, assuming it can make sense at all.  (Does this mean we can foresee executing a future probability update, but can't go ahead and update now?)

As you know, I don't spend much time worrying about the Large Hadron Collider when I've got much larger existential-risk-fish to fry.  However, there's an exercise in probability theory (which I first picked up from E.T. Jaynes) along the lines of, "How many times does a coin have to come up heads before you believe the coin is fixed?"  This tells you how low your prior probability is for the hypothesis.  If a coin comes up heads only twice, that's definitely not a good reason to believe it's fixed, unless you already suspected from the beginning.  But if it comes up heads 100 times, it's taking you too long to notice.

So - taking into account the previous cancellation of the Superconducting Supercollider (SSC) - how many times does the LHC have to fail before you'll start considering an anthropic explanation?  10?  20?  50?

After observing empirically that the LHC had failed 100 times in a row, would you endorse a policy of keeping the LHC powered up, but trying to fire it again only in the event of, say, nuclear terrorism or a global economic crash?