Science is about explaining the data, and "the data" includes our perceptions of the world. In fact, that is all that we have direct access to. So... our perceptions of the world include a constant stream of overwhelming evidence that the world is classical, a 3-D space inhabited by objects that exist in particular places at particular times. So when evidence comes along that this isn't actually true, it can cause some pretty severe cognitive dissonance, and at best it demands an explanation of why the world appears classical even though it isn't. That has nothing to do with science being "about the internal world as well as the external world." Science is about explaining the data. The (hypothetical) existence of internal and external worlds is part of one possible explanation.