How (not) to avoid the G-world in cosmology?

The first chapter’s title in Mary – Jane Rubinstein’s recently published book entitled Worlds Without End. The Many Lives of the Multiverse is: How to Avoid the G-word.
Namely, the God.
It is an interesting trend that not trying to avoid the G-word is an acceptable attitude for some modern cosmologist, although the Creator’s existence or non-existence hasn't play a role in modern optics or mechanics (what is more, it is not a question in the explanation
At the beginning of the 17th century Galileo argued that there were two books written by God. One of them was the the Bible and another was the book of nature. Although it was a common belief of that age that both of them used the same language, according to Galileo, the second one used the language of mathematics. [John Hedley Brooke: Science and Religion, p. 104] Supposing the existence of a Creator who created the World for humans, it is an open question why He had decided to use two different languages, and why an exotic and complicated system was introduced to describe the physical reality created by Him. In other words: why the physical reality is so complicated that it is impossible to describe it in everyday words? Was it a necessity to hide the structure of the world behind a complicated and non-evident formulism?
Obviously, Galileo’s concept based on a kind of Neoplatonic mathematical mysticism. According to it, the fundamental structure of our Universe is not only can be described by mathematics, but the nature itself is purely mathematical. But it is not an answer for the question why decided God to choose this language.
On the other hand, a group of physicists in the 17th century refused the Aristotelian concept which stated that an explanation cannot be complete without pointing out a final cause. Since Aristotle didn’t favor mathematics as a language of world description, Galileo’s approach offered a way to deny any argumentation based on final cause, and Descartes decided to focus on immediate causes of physical events. [Brooke, ibid, p. 72]
Since then it became a tradition in natural sciences to study those immediate causes and omitting either a final cause or the intervention of a Creator. But – to oversimplify the problem – when somebody studies either the “fine-tuned” nature of our Universe or the supposed existence of multiverses, there isn't an opportunity to study his or her subject from Descartes’ approach, because there is no an existing physical event to examine.
According to Bernard Carr, “If you don’t want God, you would better have a multiverse.” Namely: if you don’t want to refer to God, then you can replace Him with the idea of Multiverse – or vice versa. The “Multiverse replaces God with what is perhaps an equally baffling article of faith: the actual existence of an infinite number of worlds.” [Rubinstein, p. 29]
We have two different strategies to handle the causes. One can choose Descartes’ approach to always focus on immediate ones – and then he or she can ask another question about the solved problem’s immediate cause. We can move forward step by step – its mathematical analogy is the potential infinity where every piece of the result is finite and it can be achieved in a finite number of steps, but this process never has an endpoint.
The other approach is more problematic. If we are allowed to ask for a not immediate cause, then we could ask what caused that cause, etc. [Rubinstein, p. 21] and the result is an infinite regress without end.

The Galileo question

It was a common argument at the beginning of the 17th century against the use of telescope in astronomy, that we knew the terrestrial circumstances, so it was possible to “correct a range of apparent instrumental distortions” [Steven Shapin: The Scientific Revolution, p. 73]. But in the case of heavenly bodies, the situation was different, since neither Galileo nor any other scientist had a reliable, new theory about the human vision. So there was no an opportunity to ascertain whether an astronomical observation was true or a mere optical illusion.
Despite of this problem, the astronomers of that age were able to work out some reliable hypothesis about the Solar System and its objects. To give an example, generalizing their mundane observations, they supposed, that the planets were fundamentally similar to the Earth, and there were mountains and valleys on their surfaces (for example, on the Moon). Obviously, these generalizations were misleading, when they tried to draw conclusions in connection with the Martian life and some other, not detectable phenomena, but it is remarkable, that their method in many cases worked.
It is not a surprise that our evolutionary past trained us to interpret usually correctly the terrestrial environment’s events – after all, it was a criterion of our survival. But this does not mean necessarily, that our mundane experiences should be extendable to the astronomical objects.
In other words: why the laws, which govern both earthly and the celestial world, can be interpreted in the same way, using our everyday experience as a starting point, while in case of quantum physics the situation is really different?
This raises two questions.

• It would be interesting to know whether intelligent species living under the surface of an ocean or in another strange environment could extend their abilities effectively to understand the world above the atmosphere.
• And it is another interesting question, whether it is a necessity that an intelligent being’s larger-scale environment can be relatively well described using their planet-based observations. 

After all, we cannot exclude the theoretical possibility of a universe where the differences between these two levels are as big as between the physics of the humans' and the quantum scale.