Saying there is no life on other planets is like getting a cup full of sea water and saying there are no fish in the sea
I think SETI recently said that if the galaxy was an ocean. We have scanned about as much os a hot tub for signs of extra terrestrial intelligence. And that is of course assuming we are even using the right tools to detect any alien signals.
this analogy is really good on multiple levels because, sure, that cup of seawater might not have any fish in it, but it probably has hundreds if not THOUSANDS of different species of microscopic organisms but if all you’re looking for is fish you may think it’s empty of life