Our Universe Scale

• Fine tuning
It appears that many of the properties of the universe have special values in the sense that a universe where these properties only differ slightly would not be able to support intelligent life. Not all scientists agree that this fine-tuning exists. In particular, it is not known under what conditions intelligent life could form and what form or shape that would take. A relevant observation in this discussion is that for an observer to exist to observe fine-tuning, the universe must be able to support intelligent life. As such the conditional probability of observing a universe that is fine-tuned to support intelligent life is 1. This observation is known as the anthropic principle and is particularly relevant if the creation of the universe was probabilistic or if multiple universes with a variety of properties exist .