Alison and Stephen -
This is really more in the realm of philosophy than physics, but here's what I tend to think...
It certainly is possible that nothing we think we know is true. But
it's also possible that what we think we know is right! And given all
of the evidence (so-called "proof") for the conclusions that we draw
about the world around us, the chances that we are right are a lot
higher than the chances that we are wrong. So even if we can't be
that we are correct, there is a fairly high probability that we are.
But is a fairly high probability really good enough? More importantly, can we afford for it not
to be good enough? We have to trust in our conclusions as being true -
otherwise we would have nothing to base anything on, which would make
everything we do pretty much impossible. But at the same time, it's
good for us to be aware of the chance that we could be wrong.
For example, take scientific research... Scientists who work at the
cutting edge of research, on really unknown things, have to assume that
what they're figuring out is true. Otherwise it would be impossible to
go about their work. But if new evidence were to come up to prove them
wrong, it would be really important for them to stay open-minded about
Life is kind of the same way. There's not much that we can be 100%
sure of. But we can make some really really good guesses. And unless we
want to go about our lives in total confusion, we have to assume that
we're basically right. So long as we keep an open mind about things at
the same time, that's the best we can do.
In any case, as I said before, this is more philosophy than physics. This is my opinion - yours may be different.
(published on 10/22/2007)