"Fine-tuning" refers to the fact that, if the numerous physical laws,
constants, and derived parameters of our universe did not take on the
small values that they do, nothing even roughly resembling our habitable
universe would have existed. Such forces as gravity, electromagnetism,
and the strong and weak nuclear forces seem to be "fine-tuned" for the
existence of complex life.
As astrophysicist Fred Hoyle observed: "A commonsense interpretation
of the facts suggests that a superintellect has monkeyed with physics,
as well as chemistry and biology, and that there are no blind forces
worth speaking about in nature."
Photo courtesy of NASA's Hubble Space Telescope.