Well tbh science now seems to be as fanciful as religion. I don't know if you have seen anything by prof Brian Cox. His programmes are all " Maybe this ". "Maybe that" then rambles about a pre universe made up from dark energy and dark matter all these suppositions mixed in with science fact. Then occasionally he will say. We don't know what dark matter is. It seems like the BBC now pushes the non existence of any higher power but cannot yet justify the science.
Well, that's what science is, we don't know anything for sure inherently. The issue with dark matter and dark energy is that we see certain phenomena (galactic rotational speed for dark matter, and universal expansion for dark energy) that don't line up with the predictions from the Standard Model according to what we observe. Apparently, there is more mass and more energy in the universe than what we can readily observe, so in the Standard Model we have to assume there is "dark" matter and energy in the sense that they're not directly observed yet. This is easier and more reasonable than just assuming that the Standard Model is false because it delivers a LOT of really good predictions, but we also know that it is not yet complete. There is no quantum gravity yet, which would definitely help with the descriptions of black holes and such. Furthermore, it is incredibly hard to make any assumptions about the early universe since it's so hard to observe and the energy densities would be so high, so the at the moment the Standard Model is a very, VERY complicated mess of theories with only particle accelerator experiments to verify, and these big expensive fuckers are just not enough to get in the right energy ranges. However, the LHC did already deliver some great results concerning some open ends of the Standard Model.
People need to stop believing that science and physics in particular are already finished and that it's already supposed to explain everything. It's not, a lot is still open. But in all the experiments we have not seen anything that breaks causality in a way that would suggest a higher power or anything supernatural. The closest to that is quantum mechanical superposition, and that is also up to interpretation, quite literally.
But as such there is no reason to doubt a deterministic universe, as on anything but the smallest microscale the universe, as far as we can tell, IS deterministic. Everything is governed by cause and effect and physical laws, even though we might not know the laws yet, and even though the relationships might be too complex to ever fully understand in the sense that we can predict the future of everything with perfect clarity.
Whatever isms we are governed by I still think a person can gain some control over their will. As you say excuses can be made for any action. (I killed that man because god told me to)[ I was only carrying out orders]. If a person decided to abandon modern day life and live in a wilderness, metaphysical things would determine some actions. ie I will not gather food today as it is pissing down with rain. Conditioning from early life, religious indoctrination is all out of our control. If we rebel it is cause and effect, the rebellion was caused by what went before. Try not to be too unambitious !
I'd agree, however, in the end the consciousness itself is the emergent result of chemical and physical processes in the brain (as far as we know). Thus we
think to have control and free will, but every thought process is also just the result of these chemical and physical processes and thus deterministic. It might be too complex to predict, but if somehow the Big Bang would be repeated with exactly the same initial conditions, it would play out the same way.
Consider Conway's Game of Life as a very simplified model. You have a square grid of cells, each of which interacts with its eight direct neighbours. Each cell is either populated or not, and there are very simple rules to wether a cell is populated or not in the next iteration. Simple rules, but they create emergent phenomenon. Start a new grid with a random pattern of populated cells and over the course of the following iterations cells will live or die, and sometimes they will form patterns that emulate lifeforms, self-propagating arrays of cells that behave in certain ways. It has simple rules, but the size of the grid makes it harder to predict the final state after N iterations of the Game due to the complex interactions that can happen. Yet, if you start a new Game of Life with the same initial conditions, it will play out the same way.
As far as we can tell, the universe would do the same, except the rules are nigh infinitely more complex, and it's likely impossible to make perfect predictions. But still, the "Game" would still play out the same way if started again with the same initial conditions.
"You", the person and consciousness, is also a deterministic process. If "you" decide to go against the grain do something different, like not clicking on a link on a whim, then that "whim" is the result of every single thing that led up to this moment in your life, and the lifes of your parents, and basically the entire universe.
Free will is a perfect illusion.
