discount all improbabilities = make probable? [closed]

Mr. Graham Hancock in his book "The Mars Mystery" quotes Hoyle, "Origin of Universe"

I saw that the answer to this question lies in what is now called the anthropic principle, which says that the fact of our existence can be used to discount all improbabilities necessary for our existence. If history and civilization were caused by the arrival of a periodic giant comet, all accident is removed from our association in time with such a comet. The arrival of the comet was random but our association with the effects of the comet is not.

The paragraph is full of riddles for me. The hardest is "to discount all improbabilities necessary for our existence" I can understand the "improbabilities" word here, multiple quite rare natural conditions should be accomplished for the human civilization to appear and evolve. What I don't understand is why we shall 'discount' (=dismiss) such improbabilities. To the contrary, I would think we should justify them , make them more probable (none of the dictionaries I use gives even distantly similar to "justify" meaning to "discount")

Oft it is natural to follow the current of the author's thought. This particular instance for me is quite the opposite. Feel myself paddling upstream against strong current. The last sentence is the example (IMHO) of the strong disagreement between logics used in the sentence and what I got accustomed is applied in the life ^H^H^H^H common sense logic.

• To 'discount an improbability' is being used loosely here. Relevant new (or otherwise additional) information alters probability values. I'd want 'the fact of our existence can be used to discount what might well otherwise be termed "the improbabilities necessary for our existence" '. // Note that you can't strictly 'make [im]probabilities more probable' (as you say) either. You can attempt to redetermine probabilities, using new/'new' data and/or better analysis, and perhaps hope that your new estimates turn out higher than previous ones. Jul 15, 2017 at 11:19
• I'm voting to close this question as off-topic because it's not about the use of English - it's just about the fact that OP disagrees with Hoyle's position. Jul 15, 2017 at 16:13
• To disagree with something I always try to understand first. That is why I asked the question. It's hard for me to follow Mr. Hoyle's reasoning. It may be because the lack of specific scientific knowledge. It is also possible that my limited English hinders me. I thought the latter problem could be resolved here. Jul 15, 2017 at 17:34
• If this question is primarily about interpretation of a book passage, you might want to try Literature SE. (I say "if" because I'm not certain exactly what you're asking here.) Jul 18, 2017 at 18:37