Yes, but life on earth is just a slo-mo firework of an initial spark of life*. It's unknown if it originated once or several times. Finding definite life elsewhere would settle that question.
I think, just the continental shift cycle of the planet would be enough to do that. We have passed through 5? Not sure and lazy.
* the exact definition of life is somewhat blurry. There could be precursors to life that aren't technically alive, but meet some of the qualifications for life and may eventually give rise to the full criteria of life.
We humans would like to think about life in terms of the bodyplan -so the intelligence- our own phyla produced. I think it is almost impossible for us to imagine an 'intelligent' organism without opposable thumbs. I doubt if we can recognise it.
Think about the 'aliens' pictured in sci-fi movies. None of it is alien, naturally, because it is human imagination. It's either developed from arthropods or tetrapods visually or some sort of mixed image produced from here and there. Xenomorphs... They're all distant relatives. So the idea is that there is a universal formula for a bodyplan based on ours? MYEH. LOL Pfffft. Yeah, Europe Report is a very underrated movie, imo.
The latest one. Look at this. This is not an alien. It has no alien features. It has the general bodyplan produced in Cambrian in the end, doesn't it? It's 'alien' because it is scary, it is scary because it is trying survive, so it attacks and eats humans who put him in a confined space, an environment where only natural resource is human. (Which as far as I understand is the main point of the movie. They're trying to teach to kids that fact. I liked the movie. Good, brief definition of life.)

Lol, the whole thing reminds me what Terry Pratchett wrote about the elves in Lords and Ladies: "If cats looked like frogs we'd realize what nasty, cruel little bastards they are. Style. That's what people remember." I love frogs, they're adorable. But the point stands. I bet cats are nastier than Calvins as sole planet residents and we obviously beat them all and we're not even apex predators.
Humans are in general very obssessed with extra terrestrial life, esp. intelligent life but in the end, while it is very unlikely they will encounter any in their species life time, I doubt if they would recognise it, if they had.
First things first, humans wouldn't respect a species shorter-smaller than them, doesn't matter how developed or smart they're. Humans wouldn't accept or respect any species, if they didn't think they're equal or superior than them in some way which is very problematic, if you discuss human intelligence and development or what we think is intelligent.
Are humans intelligent enough to recognise intelligent life? Let me rephrase that. Are humans developed enough as species to recognise intelligent, advanced life?