Some years ago
I had a conversation
with a layman
—because I am scientific I know all about flying saucers!—
I don't think there are flying saucers.
So my antagonist said
Is it impossible that there are flying saucers?
Can you prove that it's impossible?
I can't prove it's impossible.
It's just very unlikely.
At that he said
You are very unscientific.
If you can't prove it impossible
then how can you say that it's unlikely?
But that is the way that is scientific.
It is scientific only to say
what is more likely and what less likely,
and not to be proving all the time
the possible and
To define what I mean,
I might have said to him,
I mean that
from my knowledge of the world
that I see around me,
I think that it is
much more likely
that the reports of flying saucers
are the results of the
than of the
It is just more likely.
That is all.
The Character of Physical Law.
Cornell University Messenger Lectures (1964)