Q23

[Yu440]

Hi can someone explain this question for me please? I thought the fifth paragraph supported the idea that the initial condition is likely to resemble cold, empty space.

[ohthatpatrick]

The 3rd paragraph explains how thermodynamics forces entropy to flow from lower levels to higher levels, always.

Hence, if our universe was born inside a multiverse, it would be much more likely to be born from a higher entropy state than from a lower entropy state. (You'd only have lower entropy states inside the multiverse towards the "beginning", if there even is a beginning)

If we're massively confused by the science here (likely), we can use rhetorical signposts to guide us.
The 5th paragraph is support for the idea that the big bang COULD have happened from a starting point of cold, empty space. But it's not why we arrived at the "innovation" that the big bang SHOULD have started from cold, empty space.

The way we got to C & C's innovation is by trying to solve the "mystery" (line 32) that the 3rd paragraph gave us. Multiple times in the 3rd paragraph, they tell us that high entropy (disordered) states are more likely than low entropy states.

Line 33-36 is saying "a low entropy state is such an unlikely configuration that you wouldn't expect it to randomly occur". Meanwhile, a high entropy state like "cold, empty space" is a common, likely condition that would randomly occur.

Since the 3rd paragraph is telling us that small/hot/dense is rare, exotic, and unlikely,
while cool/empty is common and likely, it supports the idea that our universe's initial condition was more likely to be cool/empty.

The 4th paragraph shows how our universe could have inflated from a cold, empty beginning.
The 5th paragraph summarizes the implications that "IF we started from cold/empty space, then presumably this isn't a super exotic occurrence and there are probably many other big bangs like it."

Hope this helps.

[LauraJ885]

I didn't feel massively confused by the science, but I nevertheless share Yu440's confusion about why (C) is right and (D) is wrong.

The science is this: High-entropy = high disorder. Line 33 tells us that a small, hot, and dense universe is a low-entropy situation. The opposite of small, hot, and dense is vast, cold & empty. High entropy = cold, empty space.

The question stem is asking us for the paragraph that contains information that most strongly supports the contention that things began as cold, empty space. In other words, it is asking for a paragraph that supports the notion that there was a high-entropy start.

Patrick's explanation rightly points out that the third paragraph (answer C) tells us "how thermodynamics forces entropy to flow from lower levels to higher levels, always".

Exactly. The third paragraph tells us why it makes sense for things to have started in a low-entropy state. That's the opposite of what the question stem says it is asking for.

By contrast, the fifth paragraph (answer D) explains how big bangs can start "even [in] empty space" -- in other words, from a high-entropy state. Isn't that exactly what we are looking for?

[JessicaK163]

I shared Laura's confusion too, but Patrick's answer helped a lot.

This question is definitely one brain teaser. If we put it in this way: which paragraph lends the most support to high-entropy state being the most probable initial state, the answer is much more obvious. The third paragraph is all about how high entropy is more likely than low entropy. In fact, lines 36-40 directly state the answer (the fifth paragraph does not mention C and C's theory at all!). The fifth paragraph deals with a problem that arises from this theory: this initial condition seems incompatible with "inflation" theory. C and A's theory suggests that the big bangs (inflation) of single universes can indeed occur without a "small, hot, and dense" spot.

The tricky part is the wording of the question, "cold, empty space" never appeared in the third paragraph. Also, the fifth paragraph is so tempting because it does a good job at explaining why cold, empty space is possible (but it doesn't compare likelihood).

I hope my answer could help!

[LylaB685]

Hi there,

I'm late to the party, but I've been thinking about this for a good 20 minutes, and I think the "correct" answer is just wrong. (For context, I do have some background in chemistry and physics - which actually screws me over from time to time because counting on what seems like common knowledge to me is not the way to get a correct answer on the LSAT - as well as classical rhetoric).

I chose answer D, paragraph 5, because paragraph 5 is the only paragraph that provides any explanation of how (or even states that) a high-entropy state could function as an initial point for the creation of a new Big Bang and therefore universe within the multiverse. All paragraph 3 says is that high-entropy states are more likely to exist and that there is a tendency toward higher entropy over time, so the likeliness of these states existing increases over time. I contest that this squarely shows that these high-entropy states are the most likely to function as initial points for a Big Bang. It is not until paragraph 5 is read that you can connect the fact that higher-frequency high-entropy states are indeed possible initial points for a Big Bang at all, which then justifies the statement made in paragraph 4.

To create a parallel argument: A majority of the earth's surface is covered with water, and more of it will be covered in water in the near future because of climate change and rising sea levels. Despite this, it does not automatically follow that the most likely place on the earth's surface to find an ant colony is underwater. That only possibly follows if we establish that ant colonies can exist underwater.

It all seems like a massive assumption to me until you read paragraph 5, and, if paragraph 5 provides the clincher, it is the paragraph providing the most support in my mind - but I see this is where my argument is weakest.

If anyone disagrees, please explain your reasoning.

Good luck studying!
Lyla

[DabinL142]

I thought about this question for a while and read all of the explanations above and it certainly helped a lot. I also picked answer D but now I understand why the correct answer is B.

In paragraph 3, the author states by giving an example that random choice leads to less orderly situation than before. That is why in paragraph 4, the author states that "such a low entropy state(small, dense, hot) is an unlikely configuration". Although, cold and empty space seems counter-intuitive for an on-start of inflation, because the Big Bang process follows the second law of thermodynamics, its initial condition couldn't have been such a low entropy state to start with.

[IrisH894]

Hi, I feel like I have to join the discussion because I'm extremely confused by the explanations above. Patrick is essentially saying that cold and empty space is a high entropy state and it makes sense this way because high entropy states are much more common. I'm not a physics major, but from what I remember from high school physics class, cold & empty=low entropy. I think entropy rises when the temperature gets higher, and cold and empty is a classic system of low entropy.
Even if you only look at the article and cast away all outside knowledge, this conclusion still makes sense. First, entropy measures the level of chaos, and a system that's super cold and has nothing within it is intuitively a very orderly system, as opposed to a hot dense ball or a massive explosion. Second, the second law of thermodynamics is a physics law, just like three laws of Newton, which means that it's never ever violated. So entropy always increases with time and never decreases. To argue that the universe started from a state of high entropy (cold and empty) and then became a low entropy system (hot and dense) is going against this rule.
So, given that cold and empty means low entropy, why is answer choice C correct here? I think it's because paragraph 3 explains why the initial condition is likely to resemble cold and empty space, while paragraph 5 explains how that's possible. In other words, cold and empty is the result of logical deduction if you start from a hot and dense ball and push backwards in time using the law of entropy. The only state that can be lower in entropy than a hot and dense universe is a cold and empty universe. And on the basis of this, paragraph 5 explains how the Big Bang can occur in such an initial condition. In other words, paragraph 3 rationalizes the conclusion in paragraph 4 while paragraph 5 demonstrates that this conclusion is consistent with the occurance of an inflation.
This is the best explanation I can think of. I chose D when I did this PT and stuck with it in blind review. I'm not completely convinced either and I hope I'm not wrong about cold and empty being a low entropy state. Feel free to correct me.