What do you really think on this?
 

1) If a mountain mysteriously dissappeared does that mean that it went out of existence?

1A) If a mountain mysteriously dissappeared does that constitute that it was indeed destroyed?

2) If a moutain was completly blown up does that mean it went out of existence?

2A) If a moutain was completly blown up does that constitute that is was indeed destroyed?

1. No it means that a trucking and excavation company put in what is widely regarded as the hardest nights work in history.(See Hitchiker's Guide to the Galaxy: Douglas Adams)
1a. See answer one.
2. No it was completly blown up, but it parts still exist.
2a. Yes, a mountain being completly blown up would indicate that it meets the requirements of being destroyed.

Well, I can't really answer unless I know why you think 'destroyed' and 'went out of existence' mean two different things.

It seems like an excercise in word choice and how it changes peoples perceptions and perspectives. Policemen do this all the time when they question witnesses or suspects. Using more damaging words like crash, bang, etc when talking about a small car accident, for example, to manipulate a person's impression/memory.

Going out of existence seems to be a gradual event which one could view and experience over time. Being destroyed seems to be a sudden, perhaps unexpected, event. So, if a mountain mysteriously dissappeared I would think that it happened very suddenly, possibly without warning. It could have been blown up, but the key word is mysteriously. If a mountain was blown up I think that the mountain was destroyed. When I think of a mountain in terms of going out of existence, I think of erosion.

Nice semantics

From your statements you are suggesting that:

a. One knows at one point the mountain was physically present.

b. The mountain is no longer physically present (as a mountain).

c. The observer did not see the transition from there being a mountain present to the lack of mountain being present.

So, one really couldn't know if it was destroyed, went out of existance, beamed onto a UFO, made invisible by some secret government project, etc. One can only say that it is no longer part of the present sky-line.

:)

Destruction is fine. It's just a shift to another state of being. Removal from existence violates conservation of mass and energy and therefore is not an acceptable answer.

Yes matter does not simply cease to exist....If a mountain disapeared or was blown up it would simply be in a different forum. Such as dirt..... Different elements in the mountain by being blown up would change of course and the mountain instead of ceasing to exist would simple be in anouther form of matter.

1) No, simply my ignorance of its location or current status does not negate its existence

1A) No, for the same reason. My perspective of its disappearance is not relevent to its existence

2) Yes, if it is indeed "knowable" that the mountain is completely destroyed. And even if it does still exist it is no long in the form of a mountain.

2A) Yes, again for the same reasons as 2.

One a side note for my answers on 2, however it could be argued that, similar to my answers to 1 and 1A, that all I can ever know is my own perspective which in no way relates to the actual existence or destruction of a foreign object.

Depends. The matter of the mountain could be converted to energy with 100% efficiency, causing the mountain, in material form, to be removed from existence. If blown into tiny pieces, it is not removed from existence, because we can safely say that there are pieces of the construct known as "mountain" lying about. If it becomes pure energy and dissipates throughout the atmosphere and crust, is the mountain in existence? The mountain has been transferred to other existing constructs.