Everything physical has a beginning and an end. Therefore, everything we see and know will come to an end.
The 2nd Law of Thermodynamics is partially a universal law of decay. In essence it states that material things are not eternal. Everything appears to change eventually, and chaos increases. The effects of this law are all around us. Nothing stays as fresh as the day one buys it; clothing becomes faded, threadbare, and ultimately returns to dust. Everything ages and wears out. Even death is a manifestation of this law. Thusly, for something to be eternal it cannot be physical (in this physical universe).
God is eternal as He is not from this realm; rather He created it. People are eternal as well (their souls, not their bodies).
Entropy? Thank you for your reply Shuhak. Not everyone subscribes to this belief of course. Of the existence of a supreme being. I wonder sometimes what THEY have to look forward to in death? Nothing?
I know they don't. Even though the evidence for it is overwhelming. If, as they believe, there is nothing "up there" but an empty cosmos, then that's all they can expect - nothing. They believe that when they die they simply cease to exist. Yet try as we might, we cannot imagine yourself not existing. It's impossible. If we can imagine it then we have to be looking at it from a perspective... which means we still exist.
Shuhak 