As humans, for a long time we believed that we were the only sentient beings in the universe. Only we, given form and thought by God, were able to comprehend our own existence. That was what defined us, seperated us from the rest of life on the planet. And of course, only the planet Earth had any life at all.
Nowadays, we know that the answers are not so straight forward. We haven't found life outside the planet yet, but most scientists believe it's out there. Also, the question of sentience has gotten a lot more murky. We have a lot to learn about animal intelligence, but we know that animals can think, understand, and have a sense of self. In the Season 2 Star Trek: TNG episode, "The Measure of a Man", the question of Data's sentience is brought up. The question of what is required of sentience is asked. The answer is "Intelligence, self-awareness, and consciousness". As little as a half century ago, humans believe they were the only beings that meet that criteria. Now, we know that other creatures - Great Apes, Cetaceans, Elephants, even ravens could be considered "sentient". Lately, there's a movement that implies that believes we're grossly underestimating what qualifies as self-aware. Perhaps ALL creatures is self-aware. Does your dog know he's a dog? perhaps. It's not an extreme jump to suggest that all LIFE may be self-aware, although we don't have any way currently to test that.
But, let's go with the theory that it is. The quality that really sets life apart is self-awareness. If a thing is alive, then it IS self-aware. That would mean that plants, even fungi are aware. All the way down to Paramecium and bacteria. Now, when we think of ourselves, we are a being, right? I am "Brian". One living life form. You are "You". Another life form. The dog is "Dog", still another entity. But, that's not quite true, is it? I am not just a solid piece of mass, but a collection of organs working together. I am a heart, and a brain, and a liver, and a couple of kidneys. I am bone and muscle. And each one of those organs are made up of individual cells, which are themselves living creatures, in a manner of speaking. Certainly, a cell removed from my heart and placed in a petri dish could not survive long on its own, but along the same lines, I would not be able to survive if I were removed from the networks that keep me alive, either.
This brings me to my point. Imagine you ARE that heart cell. You have a job, you are aware of yourself, and your neighbors. You see other cells come and go, living their own lives. To you, this is the meaning of existence. There may be something bigger out there, but probably not. To think there's more to just being a cell, why that's absurd. Of course, the blood cells are always talking. They've seen things that aren't the heart. There's the lung cells that provide oxygen, and the kidney cells that clean impurities. What if the purpose of all these cells is greater than just being a cell? You might laugh at the blood cell. Of course there's not anything "more". Life is what it is. We're not part of anything bigger... We CAN'T be, right? There's no way to even fathom what such an intelligence could be.
I trust you see the similarities. To the earth, we are but a cell - a piece of the whole. This isn't a new theory, either - The Gaia Hypothesis posits that the earth is a living being, and just as we are made up of hearts and lungs and livers and kidneys, so to is Gaia made of Humans and Trees and Elephants and Turtles. And if that is so, could that life also perhaps be sentient? Could the earth be self-aware? And if it IS self aware, wouldn't an intelligence that unfathomable be godlike?
From there, we could perhaps reach further. If cells are living creatures that make up organs that make up humans, and humans are living creatures that make up the living planet, could the planet then be part of a even more incomprehensible part of a chain of life? Is the entire galaxy possibly an entity in and of itself? from there, perhaps the entire universe? It has been remarked upon several times how the broad picture of the universe resembles the same pathways of neural receptors. If that is true, the entire universe may indeed be sentient, in an incomprehensible manner. And That truly would be godlike, would it not?
There's a quote from John Green, from "The Fault in our Stars", that goes, "I believe the universe wants to be noticed. I think the universe is improbably biased toward the consciousness, that it rewards intelligence in part because the universe enjoys its elegance being observed." If that is true, Then there might be a god after all, and we are merely part of one of its organs.