Joseph, he is quoting real scientists and pointing out that, as evidenced by their differences of opinion on these issues, though they be "experts" in comparison to you and me, they, too, don't (as you say) "have any real understanding."
It should make you or anyone less inclined to have a Pavlovian awestruck acceptance of what someone says, just because he is a scientist.
For every theory advanced by one scientist, there are other scientists who disagree and prefer their own, contrasting or contradicting theories.
So how do you decide which one you want to believe?
There are many astrophysicists, biologists, physicists, etc etc, with Ph.D.s and Master's degrees, who happen to believe in the theory of Creationism.
How do you decide which one to believe? They are all scientists.
John |