The
principle that certain things are they way they are because if they weren't that way,
man would not be here to
observe them. For instance, earth has a typical
temperature where
water is liquid because if it were drastically hotter or colder,
life as we know it could never have developed, because liquid water is essential to life
processes.
A November 2000 article in Discover Magazine applies the anthropic principle (without using those words) to the values of the fundamental constants of the universe. Perhaps there are many universes (as freeborn mentions below) with different values of these constants (but most if not all of the others do not have values that permit life to exist.
The six fundamental constants mentioned in the article are:
- ε = .007, the fraction of the mass of lone protons and neutrons lost (converted to energy) in binding them together as a helium nucleus. This value allows larger atoms to form without making larger atoms so energetically favorable that all the hydrogen would fuse into helium and larger atoms too quickly.
- N = 1036, the ratio of the forces that hold atoms together to the force of gravity between them.
- Ω (value not specified), the density of material in the universe.
- λ (value not specified), the strength of some sort of newly-discovered (1998) cosmic antigravity that controls the expansion of the universe.
- Q, 1/100000, the amplitude of cosmic irregularities or ripples in the expanding universe that allows the formation of bodies the sizes of planets and stars without forming such enormous collections of matter that everything in the universe would be sucked into a giant black hole.
- D, 3, the number of spatial dimensions in our universe. See also String theory, M-theory.