There would be no way that the results of such an inspection could be confirmed or denied. Yes, it is an observation but a single one that would rely on complete faith and belief in the observer as there is no known way of confirming what they say. They may communicate their feelings to you through language but you cannot get inside their head to see for yourself. Supposing I doubt your experimental report. You could not do the same experiment youself as you are a different person comprised of different experiences so you could not replicate the situation in exactly the same way.
Apples always fall because the pull of gravity remains constant.
Heights will not always create nervousness because people are all different, no two are the same, therefore the relationship cannot be generalised in the same way. This is a tricky one, I know that if I add 6 and 9 together I will get 15 because I have been told that these 2 numbers when added together make the sum of 15. I can repeat the same test over and over again and the result will always be the same and if I ask anyone else to add the numbers together they also will get the same answer. This works on the assumption that all the people involved in the test have been told or taught the same numbering sequence as I have.