There are many principles that guide our philosophies, our thought, our reason, and even our morality. Two of the most important ones for me are the Cosmological Principle and the Anthropic Principle. Despite their opposite-sounding names, they are not mutually exclusive!
The Cosmological Principle
It can be phrased many ways, with many different connotations. The essence of the principle is that, when viewed from a larger perspective, Earth is not special within the universe. More specifically, it states that the laws of physics govern equally and universally, with no preference for any particular region within it.
To believe such a thing in ancient times was considered heretical. After all, almost all old religion positioned the Earth as the center of the universe, at least metaphorically if not physically. But the more we learned about the universe, the more we learned the fact that we are not at the center of the universe, the perhaps painful fact that we are not special. A frightening fact indeed.
In 2006, the Cassini spacecraft took a picture where Saturn eclipsed the Sun. There was a little dot in one area. At first you might think it is just one of Saturn’s moons, or perhaps a stray asteroid. Surely that can’t be anything we call special, right?
That dot turns out to be the Earth entire.
Now, on to the second rule.
The Anthropic Principle
Only those universes with the conditions to have life would be observed by such life from within. Therefore, given that we are observing our own universe from within, our universe must have sufficient conditions for life. That is to say, just for having life, our universe is not special.
With a multiverse, there may be billions, trillions, and possibly even infinitely many universes. Even if only a tiny fraction of universes support life, the anthropic principle shows that given we can observe our own universe, we are automatically in that tiny fraction.
After all, if our universe could not support life, then we cannot exist within it. So, there would be nobody in that universe to realize it cannot support life. Someone who has studied conditional probability should be able to understand this. While the chance that a universe supports life might only be 0.01% (i.e., our universe is “fine-tuned”), the chance that our universe supports life is 100% regardless, because we are already here to make the observation in the first place.
The anthropic principle says that our universe is not special, while the cosmological principle says that Earth is not special within the universe. As humans, we cannot afford to satisfy ourselves with Earth, merely one of the billions of billions of rocks in the universe. Rather, it is imperative to explore the universe and understand its mysteries.