The thing is everyone does... It's just human nature. The most empirically minded fall back on their assumptions (with no evidence), as can be seen in this thread. These people claim there is no evidence that consciousness arises from a soul, thus the brain must be a computer. Even though computers are not conscious. They see a gap and simply fill it with unfounded mechanistic assumptions rather than those that involve agency.

Could a machine achieve consciousness? No one knows!

I suspect the brain operates due to laws of physics that haven't even been discovered yet. Imagine someone from the 1700's looked at the brain. They would only see it through the veil of their understanding: chemical reactions. Sure, that is a component that is involved. It's obvious now that even with the perfect soup of chemicals we could never achieve consciousness in a beaker. Later, we discovered and put use to electricity. Now we can see the brain has an electrical component as well. With the amazing advances in computing we (scientifically-minded) see that it must be just a computer... But we don't know how it works. How can people say they are so sure that we are seeing the whole picture? It's quite likely that the electrical networks are again just a fragment of the puzzle.

Mother nature does not have to play by the rules we set for her. I'll agree that the scientific method is our best shot for gaining understanding about the world, but it has its blind spots. Be careful not to fill those in with wild assumptions that aren't based in reality either. Scientists are just as guilty of making bullshit assumptions as any other human.