The fine-tuned Universe is the idea that conditions that allow life in the Universe can only occur with the tightly restricted values of the universal physical constants, and that if any of several fundamental constants were only slightly different the universe would be unlikely to be conducive to the establishment and development of matter, astronomical structures, elemental diversity, or life as it is presently understood. [1]

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.