I would like to ask how the natural universe can be a closed system? Thanks to expansion, the majority of the galaxies and photons in the observable universe will eventually migrate out of the observable universe; how is that a closed system?
You're equating the "natural universe" with the "observable universe." There are lots of things in the natural universe that we cannot observe. Obvious examples are anything much smaller than a star in the outer reaches of our galaxy and things waaaay larger than that in other galaxies.
Moreover, since the whole purpose of the scientific method is to predict the behavior of the natural universe based on observations of its present and past behavior, it's important to note that "we," even collectively, cannot see any of the universe's past behavior prior to the era of trustworthy recordkeeping--inarguably not to any significant extent before the invention of the technology of writing made it possible for civilization's scholarship to be an increasingly reliable continuum. Wait, there's more: because of the lightspeed limitation, we cannot even see the
present behavior of 99.9999... (my math yields around thirteen decimals) percent of the natural universe, because the light that's reaching us from out there is more than five thousand years old. Our view of the other side of
our own galaxy is a hundred thousand years out of date!
In other words, except for earth and its neighborhood, whose past we can't see, we're looking at
only extremely large-scale behavior of the rest of the universe
only in the distant past. Our view of the natural universe is actually quite limited. The natural universe and the observable universe are not identical.
Nonetheless, by using the scientific method we have developed tools and procedures that allow us to extrapolate, from the behavior we've observed, a good many characteristics of all that unobservable behavior. On earth, geology gives us a magnificent view of the planet's physical past, and paleontology and DNA analysis give us a magnificent view of the lifeforms that inhabited it. In other parts of space, the lightspeed constraint has turned into an advantage, because we see utterly consistent behavior of matter and energy in all the places we can look and at all the times we can look. The natural laws we have derived hold true in a statistically enormous sample of times and places.
To use the language of the law since the language of science is terrible for communicating with laymen, our theories about the behavior of the natural universe have been proven
true beyond a reasonable doubt by reasoning from the limited present and past behavior we have been able to observe empirically, through the humble capturing of light waves by our eyes as well as through other more complex but equally valid means of observation.
As for your assertion that the majority of the matter and energy in the natural universe will eventually move out to a distance from which we no longer capture any of its photons or other waves and particles: Clearly our reception of those "observations" will attenuate over time. Instead of being bombarded by photons from Galaxy X, we'll be hit by only one every few days, and that time lapse will increase. (And this is certainly verging off into a realm of physics in which I have no expertise: does the Uncertainty Principle say that there will truly be times in which no light from that galaxy hits earth? Are light waves that discrete? Do we even know?) But if we keep collecting and analyzing data, and keep deriving theories from it, while we're waiting for that to happen (billions or trillions of years hence, if I understand the prediction correctly), perhaps we'll find another way to predict the behavior of the parts of the universe which pass beyond yet another observational boundary. Who could have foreseen telescopes and fossils four thousand years ago, or writing, in an even more distant era?
Atheism is not unscientific, it is ascientific.
"Ascientific" means "without science." Atheism is a perfect application of the Rule of Laplace, one of the basic tools of the scientific method: "Extraordinary assertions must be accompanied by extraordinary supporting evidence before we are obliged to treat them with respect."
Since science as we know it emerged as one of the tools of the Enlightenment, there has been no respectable evidence, either of observation or reasoning, to support the hypothesis that a supernatural universe exists, and furthermore that creatures or forces within it have the ability to affect the behavior of the natural universe.
Furthermore, all attempts to "prove" this hypothesis have themselves been "ascientific," to use your term. They fall into several familiar fallacies.
- Scatterbrained logic: "There are butterflies and they're so beautiful. So there must be a God."
- Instinct: "I've known since I was born that there is a God. How can you not know that as well?"
- Demand for proof of a negative instead of a positive: "Since you don't yet understand how abiogenesis works, that's proof that life was created divinely."
- Cognitive dissonance: "Even though the 'universe' is 'everything that exists,' I believe that God exists and that he is not in the universe."
After five centuries of this consistent failure to advance the hypothesis of a supernatural universe, during which everything we've learned about the natural universe consistently contradicts it, that hypothesis has passed into the category of
extraordinary. Therefore, we are no longer obliged to waste our time entertaining the type of supporting evidence that is supplied, which barely qualifies as "ordinary."
Until some truly extraordinary evidence for theism is provided, we are fully justified in treating it with the disrespect it has earned.
And that, my friend,
is scientific.
