Size doesn't necessarily equate to probability. Especially once you start factoring in the timeline (ie, even if intelligent life evolves somewhere else, it doesn't necessarily exist now). And especially when you differentiate between "life", "sentient life", and "sapient life".
We could easily be looking at a scenario where sapient life evolved elsewhere, but has already gone extinct. Or where it WILL evolve, but not for millions of years - 14 billion years seems like a long time to US, but our current scientific understanding suggests we might be living in a fairly young universe (no matter how many species evolve, one HAS to be the first - and it could just as easily be us as anyone else).
Which is not to say that life CAN'T exist elsewhere, or that it DOESN'T, but the size of the universe doesn't even remotely guarantee it does.
Pretty much came in to say this as well.
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(\/)(\/)|-| There are precious few at ease / With moral ambiguities / So we act as though they don't exist.