The branch of astrophysics called cosmology – which is not about hairdressing and permanent waves, but the study of the universe as a whole – regards the cosmos as a single entity, meaning that everything was born together and shares universal properties. The cosmos didn’t just leak in here drop by drop from another dimension, as the Steady State theory suggested. By current thinking, the nature of space, the speed of light and the value of such constants as gravity are identical everywhere. In short, we truly live in a UNI-verse where E Pluribus Unum rules: a oneness out of which the many stars and planets are free to experiment and frolic.
If this is so, then any physical truth that applies to our galaxy, such as the strength of the four fundamental forces, is identical everywhere else and throughout all of time. Such a view has dominated astronomical thought for centuries, even if a few physicists have periodically questioned it.
In 2010, New Zealand astronomers uncovered evidence that the strength of the fine structure constant, which governs the force of electromagnetism, was slightly stronger in the distant past than what we observe here, but only in the northern direction. Looking at faraway southern galaxies, the force was weaker long ago. If confirmed, it suggests that the universe has neighborhoods. Our own region of the cosmos certainly has the specific properties that allow life to have arisen, and thus perhaps ours is a special and unique place in space and time.
But no matter whether the universe has ‘hoods or is homogeneous, over 20 different “constants” and properties seem fine-tuned to allow life to exist. Change any of them – most by even the teensiest amount – and we aren’t here.
Theists point to this as proof of God. But some physicists have a different take, called the Anthropic Principle.
The phrase “Anthropic Principle” first appeared 40 years ago during a European symposium honoring Copernicus’ 500th birthday. A theoretical physicist named Brandon Carter addressed the old Copernican Principle that humans do not occupy a privileged position in the universe. Carter startled the audience by noting, “Although our situation is not necessarily central, it is inevitably privileged to some extent.”
Carter created two forms of the Anthropic Principle that are still debated today. The “weak” version addresses the fact that life can exist at only specific times and places in the evolving universe, and we obviously occupy one of these privileged positions. The “strong” version addresses physics’ fundamental constants and how they seem perfectly tweaked for life.
The weak form essentially argues that physical constants such as the mass of the proton and the strength of electromagnetism had to be perfect for life to exist; otherwise no one would be here to observe the cosmos and the issue would never arise. Had the cosmos been otherwise, no one would be around to measure the physical constants. So all these things have to be the way they are, and there’s no oddity or coincidence to have to explain. Problem solved.
Well, okay, but is this science – or philosophy? Is it circular reasoning, or perhaps a clever way of squirming out of having to explain the extraordinary physical conditions of the universe? Or is it valid, and we can just go back to paying our heating bills?
The Strong Anthropic Principle goes much further: It basically argues that life or observers are either perennially coexistent with the cosmos or the Intended End Result – so of course physical parameters allowing this must exist. Its position resembles the writings of Aristotle: The Universe’s Goal and Plan was to produce us, so the various specific physical constants and other properties pivotal to our existence had to arise to allow our existence.
Since this version suggests intelligence or even goals lurking behind the cosmos, it is brushed off by most scientists, even religious ones, as unfalsifiable (untestable in any way) and thus a morsel of philosophy or theology, and not science at all.
We’re back to Square One. We have a cosmos that’s amazingly fine-tuned for the existence of observers. Need science try to explain this? Can it?