I think the author is speaking in generalities. There are some things I believe pretty strongly because I’ve researched them exhaustively.
I believe the earth is round, though I’ve never seen it from a distance. I believe it pretty strongly.
...There are some things I believe pretty strongly because I’ve researched them exhaustively.
F=M*A
Conservation of Energy
Conservation of Momentum
As close to “Settled Science” as you can get
And yet, still open to correction if
experimentation finds exceptions
M=M0*Sqrt(1/(1-V^2/C^2))
There are some on the forum who would disagree with you vehemently.