I dislike this point because it is imprecise. What do you mean by a "why" question? How do objects fall to Earth? Gravity. Why do objects fall to Earth? Gravity.
Well what I mean by why is the overall moral question of doing the right thing for the continued survival of life on the planet. That's more or less a metaphysical thing. And we don't have that figured out. And it does not seem to me that science will provide the answer to this. As science is hierarchical and specialized. It might provide individual answers but it does not provide guidance as to how or why to use those answers. For instance why we must live or do things a certain way. It merely provides knowledge and tools and then we apply that knowledge and tools to act on the world. If we do not act properly on the world with our science we will inevitably destroy the world. Currently we use the economic paradigm as our moral compass, which seems to work in certain cases but in other cases fails. Philosophy is needed to address this sort of deficit in our economic thinking.