Just by the simple observation that the universe is much bigger than what we can actually see, we know it's filled with billions and billions of planets (from what we have seen alone, about at least 200 billion galaxies and 10^24 planets), and we keep finding more-and-more Earth-like planets (at least 40 billion in just our own galaxy). Personally, I'd be more surprised to learn we truly are alone than to learn there is other intelligent life in the universe.
That's only one side of the equation, there are >7 billion people on the planet, so there must be lots more just like you?
You only need to identify a short list of mundane idiosyncrasies about yourself, before you are identified as utterly unique, because each improbability compounds the rest right?
The list of idiosyncrasies that make Earth habitable for complex life is neither short nor mundane- not to mention life appearing in the first place.
It's a list that grows exponentially the more we learn. I think the universe would have to be much much larger to make ET a probability.
we also have the direct evidence at hand- the 'great silence' of the galaxy.
It's an interesting question because either answer is profound- but hypothetically- if it could be determined that we were in fact alone, would this give you pause, or could you write this off as yet one more coincidence?