When Dinosaur serves our image of God Science like philosophy, litterature or politics depends on the main spread ideas existing. Science is linked to the way we see the world. A unique one.
Man is unique.
If we suppose that gravitational constant G changes from time to time. We must admit that this event is not unique. There are, and there have been lots of great extinctions through the universe. Man stops being a unique, a sole creature, born after an extraordinary event. This theory about which Dirac thought , disagrees with the way we, men of christian civilisation, see the world.