If we are the only civilisation to exist in the history of the Earth, then we will probably become extinct not in mild way, but rather in a way which will prevent any other civilisation from appearing. There is higher probability of future (man-made) catastrophes which will not only end human civilisation, but also prevent any existence of any other civilisations on Earth.

I don't believe that this follows. It is surprising that we are apparently the only civilization to so far appear on Earth, but if we accept that we are, we should not assume that we have accomplished this by destroying the future.

However, while I feel strongly that this is this case, I do not feel confidant that I can express it in a way that would be understood by someone who does not agree with me.

If someone could explain clearly why I am right, or alternatively, why I am wrong, I would greatly appreciate it.

(For context, here is what I would write given my currently semi-formed understanding: "while it makes sense to compare ourselves to a time-line independent view of the world to test the probability that our assumptions about the world are correct, it does not make sense to assume that our assumptions about the world will guide the future.")