The premise of the fine-tuned universe assertion is that a small change in several of the approximately 26 dimensionless fundamental physical constants would make the universe radically different: if, for example, the strong nuclear force were 2% stronger than it is (i.e. if the coupling constant representing its strength were 2% larger), diprotons would be stable and hydrogen would fuse into them instead of deuterium and helium. This would drastically alter the physics of stars, and presumably prevent the universe from developing life as it is currently observed on the earth.
The small value of the cosmological constant is telling us that a remarkably precise and totally unexpected relation exists among all the parameters of the Standard Model of particle physics, the bare cosmological constant and unknown physics.”
Astrophycisit John Polkinghorne ( now an Anglican priest) formulates the fine-tuning in terms of six principal constants:
1. N - the ratio of the strength of the electrical forces and the strength of gravity
2. Epsilon - defining how firmly atomic nuclei bind together
3. Omega - which measures the relative importance of gravity and expansion energy in the universe
4. Lambda - the “Cosmological Constant”
5. Q - the ratio of the gravitational energy required to pull galaxies apart and their mass
6. D - the number of space-like dimensions in the universe
The arguments relating to the fine-tuned universe concept involve the anthropic principle, which states that any valid theory of the universe must be consistent with our existence as human beings at this particular time and place in the universe. In other words, even if the actual probability of our universe that supports intelligent life may be very low, the conditional probability of supporting intelligent life, given our existence in it, is 1. Even if there could be other universes, less “fine-tuned” and so devoid of life, there would be no one there to observe them.
Yup. There is a deeper question, too: The universe is very finely tuned for there to even be matter and energy, and on top of that for their to be “clumpiness” (ie, not a uniform blob), and there’s more. But all the necessary constants just HAPPENED to work out perectly for this all to happen. /sarc