I've been seeing this argument in creationist literature for a long time.
I believe it could be classified as irrational, but maybe we need to spell
out why, instead of just dismissing the argument. Most people have not
been trained in logic or scientific method.
My response would be along the lines that much knowledge of history is
based on inference. This includes not only events before humans, but
anything that wasn't written down accurately and preserved until now. And
David Hume extended the critique against knowledge of prehistory to include
even current understanding -- you see an effect, he said, but you cannot
prove its cause; causality is only a habit of mind. So there can be no
true knowledge of any process, whether humans were there or not.
Of course Hume didn't succeed in killing science with this argument; but he
did create a new career path for philosophers trying to figure out how to
justify inference.
Despite this philosophical conundrum, I think it's fair to say that science
has made some progress since the 18th century.
Apparently some young-earth creationists are so desperate to defend their
view that they are willing to tear down all other knowledge in order to do
it. Kind of like tearing down a city to get material to build barricades.
Paul Arveson, Code 724, Research Physicist
Signatures Directorate, Naval Surface Warfare Center, Carderock Div.
arveson@oasys.dt.navy.mil bridges@his.com
(301) 227-3831 (301) 227-4511 (FAX)