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I am an IT professional. More specifically in automation. I am looking for a term or phrase that describes the event when either:

a. you are watching something closely and the issue doesn't occur


b. you are not watching something at all and the issue does occur

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it's called "can i get a screenshot?" – nathan hayfield Jan 28 '14 at 23:50
Nathan - that gave me a good chuckle. You must be IT too? – chonerman Jan 29 '14 at 0:02
Chonerman - Guilty as Charged ;) – nathan hayfield Jan 29 '14 at 0:46
I always called these kinds of situations The Dancing Frog. Every time someone tries to show you the bug, it wont occur. As soon as you leave the room, it occurs for the user almost immediately. – Doc Jan 29 '14 at 14:38
I'm surprised no one has mentioned the word "quantum". This would sort of be anti-quantum: the event only occurs (exists) when you don't look for it. – barrycarter Jan 29 '14 at 16:32
up vote 26 down vote accepted

A watched pot never boils
Something you are waiting for will not happen while you are concentrating on it.

For a single-word adjective, consider stealth. Particularly during the last government, we Brits got used to usages like stealth taxes, where the general idea is you never actually see the money going.

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I would rate this up also because it fits the description but my reputation won't allow it! Thanks FumbleFingers. – chonerman Jan 28 '14 at 20:56
+1 Exactly what I was going to post. – Josh Jan 28 '14 at 21:32
@Soylent: You had plenty of time! I spent several minutes after typing the above, but before clicking on Post your Answer, looking for some mention of a suitable single word describing a "non-observable event". It seems to be a common enough concept in the world of theoretical physics, but either they haven't found/coined a term yet, or my eagle eye just wasn't focussing properly. – FumbleFingers Jan 28 '14 at 21:37
@FumbleFingers: Further than the phrase you came up with it goes to show that setting up an experiment to watch things behave naturally is a contradiction in terms! As much of a double bind as "Be spontaneous!" – user58319 Jan 29 '14 at 7:24
@user58319: Indeed. Much of the leading edge stuff coming from theoretical physics these days seems to me to suggest that the religious perspective (which I'll crudely reduce to "Man exists in order to interact with God's universe") is being replaced by a more "solipsist" perspective (again, crudely, "Our universe exists because we observe it"). But the universe is like a shy bride on her wedding night not wanting to leave the light on - when we try to look at the details, it's too dark to see. (Or reality turns out to have yet another layer of underwear! :) – FumbleFingers Jan 29 '14 at 13:52

The common catch-all term is Murphy's Law. In IT context specifically, there's the more specific term Heisenbug.

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I'd say Murphy's Law means anything that could feasibly go wrong will definitely occur, whereas OP's context is something that's definitely known to happen out in the field, but doesn't manifest in a controlled environment. +1 for Heisenbug though - not previously known to me, but I sure could have used that term many times in the past! – FumbleFingers Jan 28 '14 at 20:57
@FumbleFingers Sounds a bit more like Sod's law to me. – WS2 Jan 28 '14 at 21:09
@WS2: Indeed - but so far as I'm concerned, Sod's Law is the British equivalent of Murphy's Law. Wikipedia claims that the latter is a subset of the former, but I think that's just tosh - it's just that Americans like the Irish connotations of Murphy's Law more (plus they don't use sod so much in other contexts). – FumbleFingers Jan 28 '14 at 21:28
@FumbleFingers WS2 what you are both thinking of is actually Finagle's Law. – AJMansfield Jan 29 '14 at 1:48
I, personally, prefer Cole's Law – Jim Jan 29 '14 at 3:13

Heisenbug is a good term if this happens software, but if you're looking at something more mechanical, you might say that this is (or is the result of) a gremlin.

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The simple term for any bug that only happens when it feels like happening is "intermittent".

If you can prove that the act of observing or not observing really does affect whether it happens, it's time to investigate things like timing dependencies, threadsafety, and so on. I have indeed heard "Heisenbug" used in the past to refer to this class of problems, but at best it's a jargonish description of a broad class of bugs with symptoms that are similar in this one way.

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The expression playing hide and seek seems to fit your context.

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We IT people are often being "Microshafted" by software events that elude logic. In the real world however I refer to such an event as elusive.

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How does "non-deterministic" sound?

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Non-deterministic is completely orthogonal to whether or not anybody's watching. It merely means that it is not the programmer but the program itself (or a particular algorithm in it) that decides, at runtime, how it wishes to behave. The programmer is free to watch the program at any and all times, and his doing or not doing so has no effect. – RegDwigнt Feb 5 '14 at 10:31

Will the expression "Unobserved event" suffice?

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opto-anachronistic - happens out of order from a visual perspective

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This doesn't appear to be an actual word—Googling it gives only this one page. Moreover, it would be much more likely to be optanachronstic if it were a word. But most importantly, it would mean something that didn't fit in with the time of your eyes, which is… nonsensical. – Janus Bahs Jacquet Jan 29 '14 at 2:15
No duh ;-) rofl – user1182988 Jan 30 '14 at 20:17

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