Donn said:But, if we are to stem the tide of "anything goes", surely we have to agree on what "valid" means?
Sure, you can argue about the validity of a belief. But that doesn't make it any less of a belief (which was the point of the thread). Belief in God is a belief, as is belief that there are no gods. These beliefs don't prevent the believer from being a skeptic.
I have powerful evidence of Fluffy The Navel Of Goodness. It was an experience only I had, that prooves Fluffy's existence.
This is (if I understand you) valid evidence for me to believe in Fluffy.
No, it's a valid reason for you to believe. It's not evidence of anything.
Where do we draw the line?
Belief is personal, and isn't always "right" or "wrong." When there is evidence, that evidence may very well disprove or even prove the validity of a belief. But if there is no clear evidence then a belief is just an opinion, and doesn't necessarily say anything about the veracity of the reasons are upon which the belief is based.
You also have to consider how useful a belief is when considering its validity. What does it explain? What does it provide the believer? One could come up with all sorts of convoluted explanations why a creature like an elf might exist if it was invisible and didn't effect the world at all, but then what significance would such a creature be?
To my horror - the link seems to be broken
It has an extra period at the end of the URL. Remove it and it will work. Very impressive work, by the way (I am in a similar field as your husband).
-Bri