Who told you we non-believers think there is not something greater than ourselves? You say you were created by God, in the image of God. We make no such claims. You say you have internal life. We do not. You say you have more certainty. We do not. Where do any of us say there is nothing greater than ourselves?
Whoa! Maybe I wasn’t succinct enough given that the primary audience here are (very) conservative Catholics. I certainly make a difference between an agnostic position and an atheist position. My only issue with people who claim agnosticism is they often do nothing spiritual, it’s just safe, uninvolved position.
Now as to that claims… I’m an Engineer by training and happen to have a pretty liberal social outlook. Eternal life (I’m assuming you meant external not internal as that would be about a soul I’d guess), I can only hope for. What else is there? Being the image of God, to me that is a message of equality. We are all made equally.
I also would not claim more certainty. All I can be certain of, especially pertaining to Jesus, is that much of the New Testament has at least historical some historical basis. Academically there seems to be little refutation that a man named Jesus was running around 2000 some years ago and stirring things up big time. There are 3rd party references to him and people like Pontius Pilate were real. Paul is also widely accepted as a real man too. Now the difference is faith, not just among Christians, but also Muslims, and to some degree Jews.
Now, with essentially an Applied Physics Degree, science is a big thing for me also. The wonder of the Universe and the mere fact that we started as a bunch of particles floating in space that combined and evolved into something that can understand that fact to a fairly decent degree. But I also know that we can’t know everything if the light (energy) of something is going away from us, we will never be able to observe it. I am
no creationist, but if you read the Jewish and Christian creation stories the is some amazing coincidences to what we know scientifically about creation. I make no point of faith by that, I just find it worth noting.