Fine Tuning Study Guide

It's been argued that the fine tuning of the universe provides compelling evidence for God. Briefly explain this argument.

We've discovered the existence of life depends on many coordinated, highly fine tuned factors. For many variables, a slight change would eliminate the possibility of any kind of structure or complexity. This provides evidence that there is an intelligence behind the cosmos

A common response to the fine-tuning says: "If this weren't the kind of universe that could support life, you wouldn't be here. So you shouldn't be surprised to find yourself in such a world." One well-known reply to this is the so-called "Firing Squad Parable". Recount the parable.

Imagine facing execution before a firing squad of 50 sharpshooters. If after the shots were fired, you found yourself still alive, you wouldn't just say, "Well, I shouldn't be surprised. If I'd been killed, I wouldn't be here to ask what happened". Something more is clearly going on.

If someone told you they randomly solved a Rubik's cube blindfolded after a few minutes, you'd have every reason not to believe them. Why would you be skeptical and how does this relate to the universe?

Number of unsolved states vastly outnumbers the number of solutions. Likewise, everything we know tells us the set of possible universes that could host life is vastly outnumbered by universes that could not. We reasonably conclude the present arrangement is not mere chance

We've spoken about the difference between unsurprising and surprising improbable events. Explain the difference using the lottery illustration we discussed in class

It would be unsurprising if Jack won the lottery out of billion participants. However, although the probability is identical, it would be surprising if Jane won the lottery out of 1000 people three times in a row.

If a monkey types "asdfjnalsjdfuiwe", we don't think it's a big deal. But if he types: "I want a banana!", we conclude something fishy is going on. But if the raw probability is the same, what's the difference?

Random letters & arrangements of molecules may be improbable, but they're not specific. The other arrangements are both improbable and specific. Together, this gives them a quality called specified complexity - unmistakable sign of intelligence.

What is the significance of the observation: "Those seeking evidence of fine-tuning appear to have embarrassingly much at which they can point. A force strength or a particle mass often seems to need to be more or less exactly what it is not just for one reason, but for two or three or five."

The values involved in fine tuning often have to satisfy multiple requirements simultaneously. This makes the idea it's some kind of coincidence far less plausible.

In order to explain for the fine-tuning of the universe, some scientists have turned to very unconventional explanations. We looked at two of the arguably more "far-fetched" explanations. What were they?

1. Simulation hypothesis: Notion that we are living in a sophisticated computer simulation
2. Time travelers from an advanced civilization traveled back to the beginning of the universe & fine-tuned the cosmos for their own existence.

Explain why the Simulation Hypothesis is probably not a good candidate for an ultimate explanation of fine tuning.

A civilization capable of creating a simulation is almost certainly living a universe that is itself fine tuned. This doesn't solve the problem, it just kicks it up a level.

Gottfried Leibniz argued that there are two and only two kinds of existing things - contingent things and necessary things. What is the difference?

- Contingent things: may exist or not (their existence is possible). They can come into being or stop existing. And their existence is explained by something else external to them.
- Necessary things: have the reason for their existence in their own nature. They cannot not exist, but exist necessarily by logical or metaphysical necessity.

What philosophical conclusion did Leibniz come to based on his understanding of contingent and necessary things?

The set of all contingent things (the universe) has to owe its existence to something necessary. If you keep following the line of explanations back, the final explanation for everything must be a necessary things.

Which eminent physicist made the following statement: "The laws of nature form a system that is extremely fine tuned, and very little can be altered without destroying the possibility of intelligent life as we know it."

Stephen Hawking

What is the multiverse hypothesis?

Idea that our universe is just one among many universes

For our purposes, why is the multiverse hypothesis significant?

It's the leading hypothesis when it comes to trying to explain fine-tuning apart from God. proponents argue if you have enough universes some of them are bound to be right for life.

Many argue the multiverse hypothesis is more speculative philosophy than something that can rightly be called science. Critics claim there are certain things about the idea that make it fundamentally unscientific. What kinds of things?

It is arguably untestable, unfalsifiable, and makes no predictions.

one of the earliest scientists to observe fine-tuning was the eminent cosmologist Sir Fred Hoyle. Hoyle's comment regarding what he called a "common sense" interpretation of the date is particularly memorable. What did Hoyle say?

"A common sense interpretation of the facts suggests a super-intellect has monkeyed with the physics, as well as with chemistry and biology."

It is becoming increasingly clear that the multiverse relocates rather than solves the problem of fine tuning. Explain.

Multiverse theories make many assumptions and require multiple things working together in very specific ways. Even multiverses need fine tuning. There are meta-laws and very specific conditions that have to be met to have a stable multiverse capable of generating universes

Some claim a multiverse requires that every logically possible universe really exists. That means a vast number of copies of you will follow every possible timeline of events branching out from the present moment. However, this seems difficult to square with our experience of the way the world works. Explain.

Reality seems to move forward in a way that makes some kind of sense. But if every possible version of the world must exist, it leads to absurdities. (So, there's a real version of the future where next year you lead a successful coup and end up living in the White House with BTS and sea lion named buttercup)

It is often argued that in a large multiverse (especially an infinite one) anything that can happen WILL happen. Leaving aside the absurd scenarios, what problem does this create for the multiverse as a theory?

We should be highly suspicious of a theory that can explain any and all observations. If any data can be made to fit, we have no way of assessing its validity. It's arguably not a true theory at all.

There are good reasons to believe that a multiverse could not be truly infinite. It could be large but would still have to be a finite (limited) set. Explain.

"Actual infinite" is generally considered logically impossible.

We can talk about an infinite number of abstract objects like numbers, but serious paradoxes and problems arise when we talk about an infinite number of existing things (whether stars, seconds, unicorns or universes)

Suppose you sat down and flipped a coin 20 times and it turned up heads each time (a 1 in a million event). A friend says, "right now a million other people are flipping coins around the world, so you shouldn't be surprised". Why is he wrong?

When something happens, you assume "typicality". Here, you assume you're just a typical random sample out of the million people involved. There is still a 1 in a million chance that it's you, so it's still shocking!

We can only see one universe, but according to critics of the multiverse hypothesis, the concept of "typicality" provides strong evidence that the hypothesis is false. Explain.

A full fine-tuned universe would be very rare among all of the places an observer could find himself in a multiverse.

Typicality - tells us we should be typical observers. The fact that we are NOT, strongly indicates the multiverse hypothesis is false.

Recently, three leading cosmologists were able to conclusively demonstrate something that has some pretty significant philosophical implications. What does the Borde Guth Vilenkin Theorem allgedly prove?

Any expanding cosmology (either universe or multiverse) cannot be extended eternally into the past. It has to have a beginning.

Sometimes people will say: "Hey, we only have one universe and one set of laws! We have nothing to compare it to, so we can't say it's improbable or judge whether the cosmos is the result of blind forces or intelligence." However, in class we borrowed an illustration from John Leslie's book Universes to argue that this way of thinking is misguided. Explain the argument.

We only have one universe, but we're familiar with what blind forces and intelligence can do. Built into the fabric of the universe are a series of hyper precise values that result in something significant - life. Leslie argues this is like finding a meaningful message (like a text) encoded in the laws of nature

List three main versions of the multiverse we looked at, and explain why they probably cannot account for fine-tuning.

1. "Many worlds interpretation" of quantum theory: deals with different alternate branches of this universe, so it can't really explain the laws & constant of our physics.

2. Inflationary cosmology "bubble universe" multiverse: The fundamental laws & constants are thought to be the same in all the "bubble universes"", so it only involves changing "initial conditions"

3. String theory: makes a very large number of unproven assumptions and has repeatedly failed to make good predictions or match observations. It's increasingly looking like a hopelessly wrong notion that doesn't describe our world.