Metaphysics: Existence of Unobserved Events

Someone wrote:
"Just because we hear an alarm clock when we are in hearing distance of it doesnt mean that it still makes a noise when we can't hear it."
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That is a neat and sound argument. The question is whether it is correct to infer/hypothesize the existence/occurence of events that are not observed. Let us call such inferences by the name "inference X".

Let us begin with asking why we infer that events have happened/will happen even in the absence of observation. Irrespective of the nature of the real world, or whether there is any reality beyond our perceptions, etc. the inference of events without observation yields a simple and fairly consistent picture/theory of the world (of reality/of perceptions?) making it easy for us to comprehend and understand it. To this most of us will agree. Thus, we know the usefulness of the inference X. And, therefore, inference X can be used until it is falsified even though it may not be verifiable.

Now, having admitted the utility of inference X, are these inferences correct? Clearly, the answer will depend upon the verification of the inferred event. Since the observer has not directly perceived the event and only inferred it, he/she must depend upon other means of verifying. Then we are led to the question: what are the other sources (i.e., other than one's own perceiving something) on which one can rely on as an evidence to the occurence of some event ?

I will not attempt a reply to this question. Because an answer to it will vary according to what sources we trust? But let it be clear that holding perception of the event by oneself as a reliable evidence of the occurence of that event is questionable too. That is, I could just as well express the doubt: just because I hear an alarm clock does not mean that the alarm clock is making the noise. The doubt, as can be seen, will turn out to be important in case of observers with hearing aberrations.

However, in raising this doubt I am not merely thinking of some stray pathological cases. Philosophically, the doubt is even more important. The manner in which you resolve it determines the kind of picture/theory that you prefer to have about this universe. And the incorrectness of that theory will be determined if it leads to some incorrect fact (which in turn should be verified/falsified using the methods consistent with the theory being tested). Meanwhile, there is no denying the possibility of the existence of many competing theories. In some of these, the alarm clock will sound when you can't hear it. In others, it won't.