Paragraph Summaries
- Typical action movies are full of things that would kill the hero, but don’t. They miraculously survive all number of threats and go on living.
- Our universe is sort of like that. The laws of physics had to form exactly as they did in order to support our existence. This is all rather improbable.
- Some cosmologists say that there are perhaps many universes. If so, it wouldn’t be surprising if the laws ended up “just right” in one universe: ours.
- How exceptional are our laws? We only think that physical laws are fine tuned for our universe because physicists have trouble imagining alternative laws that would allow life.
- Physicists usually just change one thing, and then observe the hypothetical universe under such laws and see if it supports life. But why change only one thing? My colleague and I have run scenarios where we change a bunch of parameters. We have thus identified several other scenarios where life would be supported.
- Does our evidence mean the multiverse theory is wrong? Some cosmologists had said fine tuning supported the idea of the multiverse.
But, we don’t think this is the case. Even though our evidence argues against fine tuning, we think a multiverse is plausible. First, some models of the universe’s beginnings would suggest a multiverse. Second, the idea of a multiverse may solve other cosmological problems.
Analysis
It’s always important to note who is talking. In this case, the author is either a physicist or a cosmologist, and they’re making a technical argument to convince experts or people interested in their field.
Other cosmologists are semi-opponents. But the authors only differ about “fine tuning”, and not about the broader “multiverse” concept.
Ok, so that was a little technical. Let’s figure out what these concepts refer to. I’m going to use a car as an analogy.
Now, in the real world, you know there are lots of cars of different sizes and shapes. But let’s imagine we have some clueless cosmologists, and they see one car in front of them.
They ask themselves whether another car is possible. But they’re stumped. If they change the size of any part, the car doesn’t seem to work. For example, they make the wheels bigger. But the wheels don’t fit the frame. So the cosmologists conclude that only this size of car is possible, and that it’s quite improbable that the car itself was ever created.
Using that analogy, we’ll look at the main concepts from the passage.
Fine tuned physical laws: This refers to the idea that only the laws of physics that we have now would support live.
Let’s use a car as an analogy. Let’s say for a car you need wheels, seats, a body, and an engine. (I am not a car expert).
The cosmologists who believe in fine tuned laws would look at a car, and say it’s the only possible car design.
Why would they say this? Well, imagine you make a bigger engine, and try to fit it into the body. It’s too big! Or if you make smaller seats, they’re too small compared to the body.
If you only change one thing at a time, you can’t get to another working car. So clearly, this is the only possible car. That’s how the cosmologists view the universe as well. Change one physical law, and suddenly the universe doesn’t work. Or at least, doesn’t support life.
Mutiverse Theory: Ok, so only one possible car/universe can work, say the cosmologists. However did this car get created? If you just try to create it randomly, you have very low odds of combining the right parts to make a working car. E.g. You end up with wheels too small or something.
But wait. What if there were multiple factories. Like millions and millions of them? And they each tried different combinations of car parts. Surely, by randomness, at least one factory would create the right combination of car parts to make a working car.
Likewise, cosmologists think there may be millions of universes, each with different physical laws. In such a case, it should’t be surprising that at least one universe has the right combination of physical laws.
This is the multiverse theory. It seems improbable to get the only possible correct combination randomly, but if you have a bunch of different factories/universes, it isn’t so improbable.
What is a multiverse: It’s a collection of universes. So, there would be other universes, separate from our own universe. We can’t see them, and they don’t affect us.
The only important thing is that these other universes have different physical laws from our own universe. If there are a billion universes in the multiverse, then by pure chance we would expect at least one to support life.
Author’s Theory – change multiple things at once:
Ok, so let’s recap:
- You need several different parts to make a car
- If you change just one at once, it won’t fit with the rest
- And there are millions of different possible sizes for car bodies, wheels, seats, and engines. It would be hard to get just the right combo by chance
- We have in front of us a working car. It’s the only car we can see (we’re cosmologists, and we’re a little clueless). We assume this is the only possible arrangement of car parts: making any change in another direction seems to break the car.
The author proposes a different theory: change more than one thing at a time. So, if you make a bigger car body, add a bigger engine too.
If you do this, you’ll find you can make multiple different working cars. They’re all different sizes and have different characteristics, but everything fits together well.
This is the author’s answer: the universe isn’t finely tuned. There are multiple different combinations of physical laws that can produce conditions for life. You just have to change more than one physical law at once.
Does the author’s theory disprove the multiverse?
Regarding the car, the cosmologists had argued that the unlikelihood of making such a car meant there were probably many car factories all randomly trying to make cars.
The author thinks this random theory is wrong: it’s easy to make different cars if you change multiple things at once. E.g. make a bigger frame, and a bigger engine and bigger wheels.
Does the author think this means there are no car factories? No, they said “certain models (e.g. theoretical theories) of the birth of the universe would lead us to expect something like the multiverse”
Translated to our car analogy, this would mean: according to some theories of how cars are made, we would expect there to be many factories, even if the factories aren’t working randomly.
Next, the multiverse concept might also solve other cosmological problems. In our car analogy, this would mean: factories also let us explain other mysteries, such as how boats are manufactured.
Hopefully that makes sense. The subject matter here is abstract, but the stuff they’re talking about is more straightforward than it seems.
Want a free Reading Comp lesson?
Get a free sample of the Reading Comprehension Mastery Seminar. Learn tips for solving RC questions
Leave a Reply