@currybutterchicken The CEO argues that because their current production methods pollute significantly less than the old methods, and that there are currently no methods that don't produce any pollution, this equates to doing all they can to pollute less and so as a result they must be an environmentally responsible corporation.

If you took this argument at face value (i.e., if this was a necessary assumption question), you would need to make the assumption that the new methods are doing all they can to pollute less. But precisely because we can't make assumptions, we shouldn't blindly believe that. All we know is that the current production methods pollute significantly less, but there's a possibility there are methods out there that produce even less pollution than that. Which is the flaw that needs to be addressed before the conclusion can be accepted.

@SammyF You're misunderstanding the stimulus. The passage argues that the probability of maintaining good health is increased by avoiding dairy foods. That doesn't mean that you're increasing avoidance, but rather that the percentage of good health is increased through the avoidance of dairy foods. AKA eliminating it.

@DylanDiSalvio Actually, B would still be wrong. If the stimulus had said, "Their falls had always been the result of vicious disregard for the people's needs", we know merely that when a regime is overthrown, it is because they failed to care about people's welfare. But nowhere is it stated that every regime with a vicious disregard for the people's needs is overthrown.

B states that the author infers the necessity of a certain condition for success from the fact that its absence has always led to failure. We know that failure (the fall of the regime) always stems from the absence of a certain condition (welfare). But we don't know if the opposite is true. The absence of welfare doesn't necessarily always lead to the fall of the regime. It's merely sufficient to do so.

Now, if the stimulus said, "The result of vicious disregard for the people's needs always led to the Arcadian government falling", B's logic would be valid. But then the flaw would be gone, since the flaw in the original depends on the absence of something being sufficient to lead to a negative consequence = the presence of that thing is necessary for the positive consequence.

@JohnnyQ Yeah, it's extremely subtle. I always have my guard up when I encounter words like "always", "only" and "never", because they usually signal the difference between a valid answer and an answer choice that's way too strong.

@ClaudiaMurvartian-Rhim I think it might be easier to start identifying the flaws present in a flawed reasoning stimulus, rather than focusing on if/when conditional logic is present. For example, this is a fairly cookie cutter flaw of confusing a part of the whole with the whole itself. The moment I read this question, I instantly knew the flaw from the logic in the last question: the author assumes that just because one thing is true for one portion of the whole (the written portion being not difficult), it must be true for the entire whole (the entire test being difficult).

When I encounter conditional logic in an answer, I usually already have identified the flaw (the more you encounter, the more pattern recognition kicks in) and I simply go from there. These flaws almost always translate to casual speech for me; for example I might say, the flaw is that it assumes that just because something doesn't always lead to another consequence it will never lead to another consequence. If I break it down, this can translate to an answer that states: the flaw is that it assumes that something that is not sufficient for something to occur never leads in part to the latter happening. But if I were hunting down for conditional logic in the stimulus in the first place I would have had a much more difficult time finding the right answer.

@CarolineKaplan From reading the stimulus, you might be able to figure out that the flaw is that just because something doesn't always cause an issue, it doesn't mean that it can't cause the issue. It's a little similar to the logic in the cookie cutter flaw where just because there's no evidence something is true doesn't mean that it must be false.

We can get this from the information that people with bulging or slipped disks don't always feel pain. But that doesn't necessarily mean that bulging or slipped disks can't cause pain in people. A similar analogy could be, just because some people who shower with contacts on don't get eye infections, it doesn't necessarily mean that showering with contacts on never causes eye infections.

So from scanning the answer choices, we can quickly find B. Just because a slipped disk isn't sufficient to cause back pain, it may partly nonetheless be responsible for back pain in some instances.

(For people who have trouble with conditionals, like me: An important thing to do for the LSAT in general is to study in depth the concepts of sufficient and necessary. When something is sufficient for something to happen, it means that if it is true, the truth is enough for something else to be true. For example, being in Texas is sufficient to being in America. It would be wrong to say that being in Texas is not sufficient to be in America.

Conversely, having a bulging or slipped disk isn't enough to say that you have back pain. So having that disk is not sufficient for back pain. But it may nonetheless be responsible.)

@sam.dane Sure, but think of it in the context of the letter writer. They're arguing that that the fact that 20,000 people signed petitions opposing the approach means that they agree the proposal would damage commercial fishing operations. That's not necessarily true — it could easily be for another reason. There's nothing that suggests that these 20,000 people specifically know anything about the extent of damage related to commercial fishing operations.

Now reverse this. If the letter to the editor says, the approach you propose wouldn't damage commercial fishing operations, and this is supported by 20,000 people signing a petition, you could simultaneously argue that this isn't necessarily true either. Like you said, we don't know the reason why they're signing the petition, and if they have expertise or not, because nothing has been stated. And so this is the weak point to the letter that needs to be addressed before we accept the argument. The reasoning flaw doesn't necessarily mean that something isn't true, just that the assumptions made need to be addressed.

@asadhaq The average income the government statistics report is the average income that families make. They refer to the same number. If the Anderson family's income is average for families, it falls roughly around the average income reported by the government.

Think of it like the average male height the government statistics reported in 2025 was 5'9.5. So if your height was the average for males, what height would you be?

@Jordanabel Only when and only if are logically identical. Both are used for necessary assumptions.

AKA, you are in Texas only when/only if you are in the US.

Or here, Roberta is irritable only when/only if she is tired.

A sufficient assumption doesn't include only. Think of it more like a can/might be.

You are in the US, so you can/might be in Texas.

Roberta is tired, so she can/might be irritable.

@Whelp We know that influence is necessary for great art, and that all great art involves original ideas. So if there is great art, it must be both influential and original. So it follows that some original art is great art, since great art can be considered a subset of original art. And since all great art is influential, some original art must be influential.

@Yosan Making an "effort to acquire" suggests that something is trying to be achieved, namely the goal of having expensive new tastes. So this would be a problem where you should equate the two through context/assumption.