not all science is observable....
I think you should throw out your little pamphlets from the watchtower; it's obvious that they've already lied way to much to you. Time for you to start reading something else.
The word "observe" certainly does not mean "to directly see with your own little eyes"
The word "observe", from The Concise Oxford Dictionary:
Observe: 1. Keep, follow adhere to, perform duly (law, command, appointed time, method, principle, science, rite, anniversary, etc.
2. perceive, mark, watch, take notice of, become conscious of (person, thing, that, how)
3. examine or note (phenonema), without aid of experiment.
4. say, esp. in way of comment
5. make remark
6. Hence ~able.
I don't say The Oxford Dictionary is always right, they do make mistakes, but they do tend to fix those mistakes when informed that they are wrong.
The watchtower pamphlets, though, just keep on lying, edition after edition, even if it is demonstrated that they are wrong. Their answer in such a case is to just lie even more.