What science can and cannot do

The scientific method has been a powerful tool for learning a great
deal about the physical world, but it is not a system for answering all
questions. The only questions science can attack are those that can be answered
by using the five human senses in one way or another. For example,
suppose that someone hypothesizes that the reason earthquakes
occur is that tiny invisible demons living under Earth’s surface cause those
events. That hypothesis is, by definition, untestable by scientific methods.
If the demons are invisible, there is no way for scientists to observe
them. One might look for indirect evidence of the demons’ existence, but
the problem is probably beyond scientific investigation.
It is for this reason that topics such as love, hope, courage, ambition,
patriotism, and other emotions and feelings are probably beyond the
scope of scientific research. That statement does not mean these topics
are not worth studying—just that the scientific method is not likely to
produce useful results.
Another question that the scientific method cannot solve is “why?”
That statement may startle readers because most people think that explaining
why things happen is at the core of scientific research.
But saying why something happens suggests that we know what is
in the mind of someone or something that makes events occur as they do.

A long time ago, scientists decided that such questions could not be part
of the scientific enterprise. We can describe how the Sun rises, how objects
fall, how baseballs travel through the air, and so on. But science will
never be able to explain why these things occur as they do.