"we have 200 billions galaxies, each of them let say 100 billion stars , so about 200 milion stable solar systems per galaxy ...
so the chance that there is somewhere an inteligent creature like human being is huuuge ...
but wait, it must be a specific planet, not to big not to small, it must be a specific distance from local sun, such planet need high destiny inner core to create huge enough magnetic field, in same solar system must be one or more gas giants to catch up the asteroids/meteors - but not to many because the planet will have not enough watter and not to less becaus the planet will have to much watter, such planet need a moon to stabilize the plant ... and so on. Then, remember, the earth inner core is a bit unique due colision with another planet .. so how it the chance on such colision if we know that direct colision between two stars is already unique? (note: this is actually what one of the Astrophysicist said "chance of colision nearly zero")
And now, how big is the chance that the colision happens with exact right one angle? (note: to allow inner core fussions and not blow up both planets) and then how big is the chance that the planet will have plate tectonics which seems to be neccesary to suport evolution/life .. and the how big is the chance that there will be life? and finaly an inteligent species?
So dad, if you divide the 200bil*200mil by all these "if" how many inteligent species are there?"
plenty.
that argument supposed that life as we know it here is a template for any life anywhere.
there is nothing to say that life cannot evolve on planets different from our own, only that life as we know it
cannot evolve on a different planet, and we only know life as it happens to exist on this one planet.
oh and also the argument rarely takes time into account.
if u want to do the match correctly you need to also multiply by all time between now and
that period after the big bang once the plants cooled down enuff to support biochemistry. (including biochemistry as we do not yet know it)
and then theres the matter of dimensions...
who is to say that intelligent life has to come in the form of a material entity?
haven't u ever watched star trek?
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as for things going wrong in the 20th century, i would like to recommend a documentary:
a very powerful piece about psychology, how we look at ourselves, propaganda and public relations etc.