Self-study
Columnist: Although much has been learned, Support we are still largely ignorant of the intricate interrelationships among species of living organisms. ██ ███████ ██████████ ███ ██ ████████ ███ ███████ ██████ ██ ███████ ██ ██ ████ ██ ████████ ██ ██████████ ████ █████ ████████ ███████ ██████ █████ ██ ███ ███████████ ██ ██████ █████ █████████ ███ █████████ ██ █████ ████████
Objective: Build the Premise -> Conclusion Bridge
The columnist concludes that if there are any species that we want to preserve, then we should try to preserve as many species as possible. This is because we don't know much about the relationships between species. That lack of knowledge means we don't know if losing a species, even if it’s one we don’t care about, could possibly put other ones at risk.
Because this is a PSA question, we're looking for a premise-to-conclusion bridge, which we can find by identifying the gap in the argument. Since we're dealing with a conditional conclusion (if we have an interest, then we should preserve), we can make this gap clearer by kicking up the sufficient condition into the premises.
Reformulating this way would leave us with the non-conditional conclusion that we should try to preserve as many species as possible. We still have the premises that we lack knowledge about interrelationships between species, and that letting some species go extinct could put other species at risk—but now we have another premise as well, that we kicked up: that we have an interest in preserving at least some species.
From here, we can identify the gap in the argument. The premises establish that the loss of a species might jeopardize other species, some of which we care about, but that doesn’t tell us why this possibility requires us to try and prevent the loss of as many species as possible. Our bridge could look something like this: if we're interested in protecting any species and there’s a risk that allowing some species to perish could endanger a species we care about, then we should preserve as many species as possible.
23.
Which one of the following ███████████ ██ ██████ ████ █████ ██ ███████ ███ ███████████ █████████
a
It is strongly ██ ███ ████████ ██ ████████ ███████ █████ ███ ██████ ████████
The conclusion is this entire conditional: if it’s in our interest to preserve any species, we should maximize species preservation. How does (A) interact with this conditional conclusion? Well, if we presume the conclusion to be true, then (A) triggers the sufficient condition, allowing us to infer that we should maximize species preservation. But we can't presume the conclusion to be true. This is a PSA question. Our job is to prove that the conclusion is true in the first place and (A) doesn't do that.
Another way to see the error in (A) is to realize that the author doesn't actually care about whether we have an interest in preserving any species. What the author cares about is that if we were in a world where we cared about preserving any species, then in that hypothetical world, we should try to maximize species preservation.
b
We should not ████ ███ ██████ █████ ███ ████████ ██████████ █████ ████ ████ ███████████ ███ █████ ████ ████████
This leads to the wrong conclusion: we know that we don't have all the relevant facts, so this would suggest taking no action at all. But we want to bridge to the conclusion that action should be taken to preserve species, which is not justified by this principle.
c
We should not █████ ███ ██████ ██ ███████ ██ ████████ ███ ███████ ████ ██ █████████ ███ ███ ███████████ ██ ███████ ███ ██████ █████ ████████████
Like (A), this basically affirms the sufficient condition of the columnist's conditional conclusion: it tells us that we have an interest in preserving some species. Also like (A), what (C) doesn't do is explain why that means we should preserve as many species as possible, meaning it still doesn't bridge the gap.
d
We should not █████ █ ██████ ██ █████ ██████ ██ ███ ███████ ████ ████ ██████ ████ ███ ██████████ ████████ ████ ██ █████████ ██ ███
In other words, if a change (i.e. the loss of any species) could jeopardize something important to us (i.e. a species in which we have an interest), then we should try to prevent the change (i.e. preserve as many species as possible). Because we know that any species loss could harm other species, this principle triggers, and bridges the gap to justify the columnist's conclusion.
e
We should always █████████ ███ ██████ ██ ██████ ████ ██ ██████ ██ ████ ███ ████ ████████████ ██ ███ █████████ ███████
The columnist does not establish that preserving the maximum number of species yields the best consequences in the near future, so this principle doesn't trigger to begin with. The argument doesn't present any prediction of which actions will have the best immediate consequences, so this just isn't relevant.