# What if you wrote "eaten by a gigantic sea-snake" in the Death Note?

I was wondering, suppose that I wrote in a Death Note,

Person A in day x, month y, year z, hour h, minute i, second j, eaten by a gigantic sea-snake.

A goes to the middle of the sea for diving. There, when he dives, a gigantic sea monster swallows him whole.

Is this kind of death possible? If so, wouldn't that make the Death Note the greatest scientific tool ever? I mean, it could be used to verify the existence of aliens too.

• Haha! Nice idea. Sep 15, 2014 at 10:00
• The alien example might not work though - it might take more than 23 days for aliens to arrive on earth, for instance. Sep 15, 2014 at 10:35
• Well, if the alien has the warp technology, they might be able to reach Earth in 23 days. :-) Sep 15, 2014 at 10:50
• Mr. Tao dies of cancer after solving the Riemann hypothesis and secretly sending me the results without telling anyone else? Sep 15, 2014 at 13:17

I'll attempt an answer.

There doesn't seem to be anything wrong with this per se, given the Death Note rules as I remember them. If sea monsters (or aliens) existed, this would be hypothetically fine as long as the conditions for such scenarios coming into play (e.g. A's journey to the sea doesn't take 24 days, or A doesn't have to fly from Urumqi to the Atlantic Ocean in an hour) are appropriate and possible. However, we run into some problems.

Obviously if sea monsters exist where A goes diving and the biology of sea monsters allows them to swallow A, we're fine. But how about aliens? What if, as I mentioned, it takes more than 23 days for them to arrive on earth?

If the aliens show up and kill A, or if the sea monster swallows him, we have proof of those things existing. But if A just dies of a heart attack, we don't know what we've "proved" or disproved. For example:

• Maybe aliens (or whatever) don't exist.

• Maybe it's impossible, at least at the moment, for aliens to show up and kill A within 23 days, because they don't have the appropriate technology.

• With kaine's comment - maybe the mathematician simply isn't capable of solving the Riemann hypothesis that quickly for whatever reason.

So if we get a "positive" result, we're good. But if we get a negative one, we probably won't know why exactly such a result occurred, and in that sense this technique doesn't quite work (or rather, it wouldn't be as useful as one might imagine).

• That's pretty much how hypothesis testing in statistics works too--if your hypothesis test confirms the hypothesis, great, but if it doesn't, then it's said that the test "fails to reject" the hypothesis--you can't make a call on it either way. But we could increase our confidence in the result by having aliens kill as many people as possible; either we'll get a "positive" answer at some point, or we can say that the probability that aliens exist asymptotically approaches zero as more and more people fail to be killed by them. A very Mengele way to practice science. Sep 15, 2014 at 22:22
• @Torisuda: But in a sense I think what we're testing is really just "Aliens can kill people given the conditions of the Death Note and other circumstances." It's obviously true if aliens exist (and the person dies that way), but it's "false" if aliens don't exist, or even if aliens can't travel or kill people that quickly. Sep 16, 2014 at 4:03
• Agreed, if we repeatedly write "Aliens kill X" for several values of X, and our Xs keep dying of heart attack, we can never conclude that aliens don't exist, even if we spaced our trials out at 23-day intervals over a long period (say a hundred years, or even a thousand), as you cover in your answer. Sep 17, 2014 at 0:00
• (cont'd) I was trying to point out something implicit in your answer, that even if we applied the Death Note's "magic" to scientific questions like this, in some sense we haven't really gone anywhere--it still comes down to statistical confidence. Even with "magic", we're just increasing our confidence in the conclusion, and even then, only if it confirms our hypothesis. And as you also point out, we add a bunch of new possible explanations for failure, because we also have to deal with the Death Note's rules. I thought that was an interesting consequence of your (very sensible) logic. Sep 17, 2014 at 0:06
• @Torisuda: Definitely agree. (I think I just somehow misread something in your original comment, or assumed that the "trials" involved in the experimenting you mentioned all involved the same conditions, which, well, wouldn't work effectively.) Sep 17, 2014 at 8:45