“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.”