Ever since human beings have been capable of thought, we have asked big questions about
how the world around us works.
Some people have thought that there is another reality beyond the one we can perceive through
our normal senses -- a supernatural world where there might be ghosts and goblins, gods
and demons.
They have thought that knowledge can come from this source -- from supernatural revelations,
prophetic visions or divinely inspired books.
Others have thought that the way to learn is by observing the world around us carefully
and in detail, forming ideas about why things behave as they do, testing those ideas through
experiments, refining them in the light of experience, then testing them again.
Out of all the various methods that people have tried to use to find out how the world
works, observation, experimentation and the testing of theories against evidence has the
best track-record.
Prophets have predicted the end of the world on many occasions, but we are still here.
Ancient holy books contain a description of the universe which has turned out to be totally
inaccurate.
If asked to choose between taking a medicine prescribed by a doctor whose methods are based
on experiment and one who has selected medicine for you based on his visions, you will probably
not choose the medicine from the vision.
We may never know everything.
But the testing of theories against evidence has proved itself again and again to be a
reliable way to gain any knowledge about how the world around us works.
Through science we have cured deadly diseases, created amazing technologies, and learned
things about the universe that fill us with wonder.
When we want to know what's true and what is false, there is no better method.