Scientific discussion can include speculation. Religious ideas can be part of the discussion as speculation.

I believe some ideas, thought of as religious or supernatural, can have validity as speculation. In science, there are many lines of thought that are speculation; for instance String Theory in cosmology. Scientists often speculate about big ideas beyond what's considered more proven fact.

String Theory, Quantum Gravity and other ideas, on the frontiers of physics and cosmology, are fodder for educated discussion. There may be a time in the future when more clear evidence becomes available bringing some these ideas into the realm of more fact, or on the other hand, these ideas might be discarded. In the past ideas that societies had about the earth being flat have been discarded, for the most part.

Speculation about big questions such as what brought the universe into existence, the meaning of life, whether there is any intent or design to the universe beyond us and even speculation about an afterlife, is all fodder for good discussion.

There is still a lot that we don't know. I think religion makes a mistake when speculations about these things are thought of as being proven fact. Speculation does have a place in real science, but speculation shouldn't be confused with more proven fact.

Thousands of years ago, many societies thought it was a fact that the earth was flat. This was based on the evidence one sees just standing on the level ground. We could have stuck to those so called facts, or we could speculate and explore the possibilities of things beyond that worldview.