Is the Universe Fine-Tuned for Human Life?
Gazing in Awe at the Universe
What Is the Fined-Tuned-Universe Notion?
In simple terms, the argument for a fine-tuned universe states that the probability of the various mathematical constants of the universe being exactly what is needed for life is so unlikely that it could not have occurred just by chance. Therefore, an “Intelligent Designer” (God) must have created the laws of physics in order to create a universe that was capable of supporting human life.
At first glance, the argument seems to make sense. But a little bit of thought will show you that the assumption of a fine-tuned universe doesn't make sense. The better assumption is that life fine-tuned itself, via evolution, to fit the conditions found in the universe.
If the laws of physics were different, there would be no universe, and if the laws of chemistry were different, there would be no life. In that case, there would be no humans to say the universe was fine-tuned for them.
Let’s look at some of the reasons against the notion of a universe created and fine tuned-for the existence of life, and more specifically, for the existence of human life.
What Are “Mathematical Constants”?
Let’s begin with a look at mathematical constants.
The term “mathematical constants” refers to unchanging mathematical values that are observed in the universe. For instance, pi is a constant; the speed of light in a vacuum is a constant. In order for the universe to exist, dozens of these constants, the “laws of nature,” must have exactly the value that they have.
Physicists have developed “The Standard Model” to describe everything known about the universe from quantum mechanics on the sub-atomic level to the cosmological forces such as gravity, electro-magnetism, the weak nuclear force, and the strong nuclear force. It also includes things like the mass and charge of electrons, protons, neutrinos, and quarks. Even the Earth’s orbit must be almost precisely what it is.
If any of these mathematical constants were different, the universe could not exist. It would have either collapsed in upon itself or been unable to hold itself together. Stars and planets could not form the elements necessary for life (like carbon), and the chemical and biological processes that produced and now sustain life could not occur.
How can we explain what seems like a remarkable and improbable coincidence of all the mathematical constants,being exactly as they are in order for our universe (and us) to exist?
A Famous Formula
What Is the Anthropic Principle?
There are two anthropic principles, the weak anthropic principle and the strong anthropic principle. They were put forth by astronomer Cater Brandon in 1974.
- The weak anthropic principle is the idea addressed in the first section of this essay. The fact that we exist means that the universe must have the characteristics that allow us to exist. If they were not, we would not be here to muse about why we are here. This principle is widely accepted
- The strong anthropic principle is more controversial. It states that only a universe that is capable of sustaining life at some point of its existence is capable of existing. Since we live in a universe that is capable of sustaining life, we must therefore conclude that only life-sustaining universes are possible.
Cosmologists have since come up with 30 additional variations of the anthropic principle. For example, one draws upon quantum physics--it states that no universe can be real until it is observed.
What Are the Odds for the Existence of Our Universe?
The probability that all of the mathematical constants would be exactly as they are by random chance has been estimated to be 1 part in 10 to the power of 234. Those are really long odds.(UCF News)
However, that calculation results from a misunderstanding of probability. Probability theory is used to predict future events, not to explain the likelihood of an event that has already occurred.
The probability of all the mathematical constants being exactly what they are is 100% because it is something that has already happened.
What Is the Principle of Mediocrity?
Cosmologists now know that our solar system is not unique. There are many other stars with planets. Many of these planets are similar to Earth in terms of mass, density, orbit, chemical composition, etc. Some of them even fall within what is called “The Goldilocks Zone” of their star. (This is the zone in which liquid water can exist, neither too hot nor too cold. Without liquid water, life as we know it cannot exist. Fortunately for us, Earth is within the Goldilocks zone.)
There is nothing special about our sun and our planet—they are mediocre. If they were unique, the fine-tuned argument would be stronger.
An Infinite Number of Universes
Are There an Infinite Number of Universes?
Some cosmologists posit a multiverse where there are an infinite number of universes. Some of these other universes may have different physical constants. If so, it is not improbable that one of them would have the physical constants that make life as we know it possible.
Think of it this way. Let’s say you buy a lottery ticket and the odds of winning are one in 100 million. Let’s assume that all the tickets are sold and each ticket has a different number. It is very unlikely that your one ticket will be the winner. However, there will be ONE ticket that IS the winning ticket.
In this analogy, the lottery tickets represent all the possible universes and the winning ticket represents a universe in which human life exists. The odds are impossibly high only if you think the purpose of the lottery is for your one ticket to be the winning ticket. If you don’t care which ticket wins, the odds are 100%.
Are There Different Kinds of Universes?
We can only look at one universe, the one we live in. We can’t make good judgments about what is possible based on a sample of one.
If there are infinite universes, maybe every one of them is exactly like ours because the laws of physics allow no variation. Maybe gravity must be exactly what it is—there is no range.
Or, maybe the constants are not independent. If gravity is has a particular value, then the speed of light and all the other mathematical constants must be at a particular value.
An Asteroid Strike
Why Is the Universe Always Trying to Kill Us?
If the universe was created to be perfect for us, why is the universe (an even the Earth) constantly trying to kill us?
Earth doesn’t seem so fine-tuned for human life to me.
- There are lions and tigers that can eat us. There are spiders and snakes that can poison us.
- There are tornadoes and hurricanes that can toss us about like rag dolls.
- There are bacteria and viruses that can infect us with diseases that kill us.
The universe is trying to kill us also. The radiation found in outer space is deadly. (Even radiation from our own sun can give us skin cancer.) And comets and asteroids could crash into the Earth at any time. The universe seems to be a pretty lethal place.
Why Are Humans So Badly Designed?
If humans are designed, why didn’t the designer do a better job of it? Why do we have “bad backs,” poor eyesight, imperfect memories, etc? Why don't we have three hands? How many times have you said, "I wish I had a third hand."
Maybe because evolution formed us to be just good enough to survive as a species; nature doesn’t need us to be perfect.
Humans don’t appear to be fine-tuned.
Are Humans Really the Purpose of the Universe?
Humans appear to have evolved on earth by chance. If a comet hadn’t hit the Earth resulting in the extinction of dinosaurs, it is likely that the only mammals on this planet would be rabbit-sized and rabbit-brained. Dinosaurs would still rule the Earth, and maybe those dinosaurs might think the Earth was made for them.
Of course, God could have sent the comet to kill off the dinosaurs, but why create them just to kill them off. And if He killed off the dinosaurs, can you really be sure that He will not kill off the humans some day. Maybe He sent atomic weapons for that purpose.
Is the Idea of a Fined-Tuned Universe Just Anthropocentrism?
The fine-tuned argument assumes that the purpose of the universe is human beings. What if the universe has no purpose? What if the universe just exists, and here and there conditions are just right for life?
Humans do not seem to be the purpose of the universe. I doubt the universe has a purpose, but if it does, maybe humans are just a by-product of this other purpose.
There is no reason to think that God or an Intelligent Designer created the universe just for humans. It is just speculation without any basis. You might as well say an alien species from another universe created this universe and all it contains, including us. Or maybe it is all a simulation on a video game—Sim-Universe.
If the existence of the universe is improbable, isn’t it even more improbable that an “Intelligent Designer” created it.
A Famous Quote from Douglas Adams
What is The Puddle Analogy?
Douglas Adams, best known for his quirky science fiction novels, came up with the perfect analogy that illustrates our anthropocentrism. It was part of a speech he gave at a 1998 conference, Digital Biota 2, at Cambridge, U.K.) It was later incorporated into his posthumous book, The Salmon of Doubt: Hitchhiking the Galaxy One Last Time(2002, Harmony Books. p. 131)
“Imagine a puddle waking up one morning and thinking, ‘This is an interesting world I find myself in — an interesting hole I find myself in — fits me rather neatly, doesn't it? In fact, it fits me staggeringly well, may have been made to have me in it!’ This is such a powerful idea that as the sun rises in the sky and the air heats up and as, gradually, the puddle gets smaller and smaller, it's still frantically hanging on to the notion that everything's going to be alright, because this world was meant to have him in it, was built to have him in it; so the moment he disappears catches him rather by surprise.”
I'll let Douglas Adam have the last word.
The Grand Design
This essay was inspired by reading "The Grand Design" by Stephen Hawking. Most of the facts about cosmology, physics, and mathematical constants that I cited in this essay were taken from this book. (The opinions are my own.) Hawking and his co-author , Leonard Mlodinow) have produced a very readable book that took me through the history of human thinking about the universe and brought me to the cutting edge of the strange and wonderful science of modern cosmology.