We don't even know if it will be ever practical interstellar travel, because we didn't reach that stage yet. In theory it should work... in theory I could climb stairs till reaching the moon too. People is too busy trying to figure out how advanced aliens should think, and didn't stopped to analyze how they are thinking
By using our knowledge of physics, we can make reasonable speculation on what is possible and not possible, and what engineering we need to do to make these effort successful. Some people's work are so successful that they became foundational to our knowledge base today.
Same as with aliens. We can make reasonable extrapolation on what we might see from the type of aliens that expand versus and aliens that don't. They are of course, guesses, and those guesses continued to be argued and refined. Note that the site doesn't assumed that all aliens are grabby, only that some are grabby aliens, and try to extrapolate on what it might look like if they are grabby.
> By using our knowledge of physics, we can make reasonable speculation on what is possible and not possible, and what engineering we need to do to make these effort successful
Our speculation is only as good as our understanding of physics. Which is pretty good! But people in 1800s thought they had discovered just about everything to be discovered, and thought themselves at the end of physics, too.
Eh, people like to extrapolate by analogies. Doesn't actually mean that it's true.
We can only reasonably speculate using our existing knowledge base. Doesn't mean that people literally think we know all there is to physics. People even acknowledged that it's incomplete.
By using our knowledge of physics, we can make reasonable speculation on what is possible and not possible, and what engineering we need to do to make these effort successful. Some people's work are so successful that they became foundational to our knowledge base today.
Same as with aliens. We can make reasonable extrapolation on what we might see from the type of aliens that expand versus and aliens that don't. They are of course, guesses, and those guesses continued to be argued and refined. Note that the site doesn't assumed that all aliens are grabby, only that some are grabby aliens, and try to extrapolate on what it might look like if they are grabby.