 For example, James Gregory, Isaac Newton and Christiaan Huygens were able to estimate the distance between Sirius and the Earth through this method.The mediocrity principle is in contrast with the anthropic principle, which asserts that the presence of an intelligent observer (humans) limits the circumstances to bounds under which intelligent life can be observed to exist, no matter how improbable.Both stand in contrast to the fine-tuning hypothesis, which asserts that the natural conditions for intelligent life are implausibly rare.