The Anthropic Principle, Dismantled

It is no secret that the Universe looks finely tuned for life. This is a problem for atheists because a finely-tuned universe seems to point to a Designing Intelligence behind the existence of the Universe. As famous physicist Fred Hoyle put it: “A common sense interpretation of the facts suggests that a super-intellect has monkeyed with physics, as well as with chemistry and biology, and that there are no blind forces worth speaking about in nature.”

To try and explain away the fine-tuning of the universe without reference to an Intelligent Designer, some atheists have become rather fond of a philosophic device known as the “Anthropic Principle”. There are various, often conflicting definitions of it, but in this article, I’m going to break down the essential point for you.

Sleight of Hand

The Anthropic Principle at its heart actually is a neutral statement. Formally, it is defined as a:“philosophic consideration that observations of the universe must be compatible with the conscious and sapient life that observes it.”

Confused? Let me give you an example of it in action.

A finely-tuned universe is one in which the laws of nature are very precisely set so as to permit life to exist. For example, the Cosmic Energy Density, which is a description of how tightly packed the universe was in its early stages is finely tuned to 60 decimal places. In other words, if it was 1 decimal place in 60 too small, all matter would have expanded too quickly in the Big Bang, preventing the formation of galaxies and stars. If it was 1 decimal place in 60 too much, the universe would have collapsed back in on itself and never expanded.

“1 in 60 decimal places? Pish posh. That’s nothing,” I hear you say. Well. Let me put it like this:

To change the mass of sun by 1 in 60 decimal places, you would only need to add or remove 2 electrons.

Feel free to pick your jaw up off the floor.

This isn’t just about one or two constants of nature, but literally dozens of them, as we’ve explored previously. In fact, the fine-tuning of the universe for life, isn’t controversial. It’s admitted to by even the most ardent of atheists. After you’ve read this article, you can watch this video of Leonard Susskind, atheist and physicist extraordinaire, explaining fine-tuning brilliantly.

Running Forwards ≠ Running Backwards

Using the Anthropic Principle, an atheist might say:

“Hey, that level of fine tuning isn’t so surprising at all. In fact, the only reason you’re here discussing the Cosmic Energy Density level, is because it was in fact finely tuned for life.”

In other words, because fine-tuning leads to life, and because we know that life exists, our observation of fine-tuning isn’t surprising at all; it couldn’t be any other way! Thus, by taking life as a given, they portray the fine-tuning of the universe that caused it, as an inevitability. This however, is totally false. Yes, we exist and so yes, we must exist in a finely-tuned universe, but that doesn’t at all explain why the fine tuning was there in the first place. After all, the Cosmic Energy Density being finely tuned to 60 decimal places in the immediate aftermath of the Big Bang has nothing to do with the life that emerged some 13 billion years later. Our existence does not explain why fine-tuning occurred prior to our existence, because, in philosophical terms, we are not “necessary” beings. We didn’t have to exist. The universe would have got along just fine without us.

And that, after all, is the key point. We aren’t interested in what fine-tuning leads to. We know it leads to life. That’s not controversial. We’re interested in where fine-tuning comes from.

And the Anthropic Principle does nothing to answer that question.