DAVID: Cosmology: milky way size is enormous (Introduction)

by David Turell , Tuesday, June 25, 2019, 15:11 (1759 days ago) @ dhw

DAVID: Wrong again. The entire universe is viewed as fine tuned for life everywhere. All those other galaxies are just part of the whole universe and some folks consider they might bear life. Your view is too narrow.

dhw: Please explain to me how anybody knows the makeup of the entire universe, and how all the small galaxies extant and extinct that are/were not suitable for life are/were fine tuned for life, and please note the first quote in this exchange: you “suspect we are alone”.

DAVID: The entire universe has the same characteristics throughout the portion we can see with the CMB. There are arguments that other portions might be different in the multiverse theories. There are books that describe how fine-tuned he universe is, not at all confined to the Milky Way. Life is possible elsewhere, but requires the special characteristics of our Earth. I still suspect we are alone.

dhw:The argument as I understand it is that if the universal laws of nature were not as they are, matter would be different, and therefore life as we know it could not exist. You might just as well say that if there wasn’t a universe, there would be no life. It’s a non-argument. At the same time we are told that if our sun were any different and our relationship to the sun were any different, there would be no life. This argues for fine-tuning of our galaxy, but not for fine tuning of billions of other galaxies extant and extinct. We do not know if there is life outside our own galaxy, or if there was life on galaxies that have disappeared. If you tell us that OUR galaxy is fine-tuned for life, it seems to me you have a case. If you tell us that every other galaxy is fine-tuned for life, you have no case until you can prove that there is life on other galaxies. In which case, it is absurd to say that the whole universe is fine-tuned for life.

If the universal laws were different, that might be no matter at all. Our galaxy formed within the special parameters that made the universe, and seems to be a very special galaxy. There are many types of galaxies all appearing under the same rules. But all galaxies are under the same rules and diverse as they are individually. You are correct in that some special additional fine tuning applies to our galaxy and our Earth, all allowed under the general fine tuned rules of formation of our universe