It means that (1) not to just trust scientists based on some kind of moral standing, (2) just because a scientist is sure that one thing is true and another thing is false doesn't necessarily mean the opposite is so, and (3) that science never finds "truth", but has models and theories that fit to reality to varying degrees.
That looks considerable more qualified than the quote you provided from Planke.
232 posted on 12/18/2006 3:55:22 PM PST by tacticalogic
("Oh bother!" said Pooh, as he chambered his last round.)