@CeliaRattner Yes I think so! Although it may not eliminate the alternate case completely, it definitely way reduces the likelihood of other claims that could weaken our argument (ex. a claim that says Han purple was produced far away from any white glass produced so it couldn't have been discovered during glass production)

@JeremyK So I'm not sure if this helps, but for questions with a complicated stim I find it helpful to just mentally box up any info that feels too complicated / doesn't seem to be needed right away. For this question, the part about "burn steadily at a rate that produces more light than 90 billion suns" is right in the middle and just seemed complicated. But since the very next sentence says, "nothing that burns at a rate that produces that much light could exist for more than 100 million years", you can just box up the 90 billion suns part and label it as variable A. (I highlighted it to make it clear that I had boxed up that part mentally.)

So now the connection between the first part of the stim and the last part of the stim becomes much clearer. I'm able to see that 1) it takes 500 mil years for a quasar's light to reach Earth, and 2) a quasar can only exist for about 100 mil years. Since if it takes quasars light 500 mil years to appear to Earth, then that quasar that we're just now seeing is long gone --> E).

I'll go back to the boxed up info if I need it after looking at the ACs, but for this question, it wasn't necessary.

@Stas1973 Thank you for this explanation!

@SavanaTipton I like to think of this as an 'umbrella' question and thought this could possibly help you. The ethicist gives us a general principle that if one ought to do something, then one can do it, but says that's not always true and then gives an example of an exception - if someone promises to meet a friend but can't do it (it's impossible to do so because of a traffic jam).

But hold on. We've been given an example of a promise but how is that related to the general principle? The only way for this example to actually be an exception to the principle would be if the promise is under the 'ought to' umbrella. If it's outside of the 'ought to' umbrella, then this example isn't relevant at all to the principle. This is essentially what D) says. If negated, it would mean that the obligation created by a promise is relieved by the fact that it can't be kept, which is the same thing as saying that promise wouldn't be under the obligation/ought to umbrella anymore. This destroys the argument because it makes the example irrelevant to the general principle.

A) is wrong because it says that promises are the only thing under the ought umbrella, but obviously we don't need that as a necessary assumption.

Hope this helps a little!

I don't see an explanation video for this question.. is this a technical issue?