Any general statement is like a cheque drawn on a bank. Its value depends on what is there to meet it. If Mr. Rockefeller draws a cheque for a million dollars it is
The same applies with cheques against knowledge. If Marconi says something about ultra-short waves it MEANS something. Its meaning can only be properly estimated
You do not accept a stranger’s cheques without reference. In writing, a man’s name‘ is his reference.
The verbal manifestation on any bank cheque is
Your cheque, if good, means ultimately delivery of
BUT no layman can tell at sight whether it is good or bad.
Hence (omitting various intermediate steps) ... hence the almost stationary condition of knowledge throughout the middle ages. Abstract arguments didn’t get mankind rapidly forward, or rapidly extend the borders of knowledge.