They are different because A says the argument “presumes” something. B says the argument “ignores” something. If the argument had presumed that smaller fish are more susceptible than larger fish, we should be able to locate where in the argument that is addressed, but we can’t. Thus, A isn’t accurately describing anything going on in the argument. However, B does accurately describe that the argument ignored effects on smaller fish in larger bodies of water with more diverse ecosystems. Hope that helps!

I got this one wrong because I read the stimulus as setting up two contrasting types of entities: those posited on the most explanatorily powerful theory v. those posited solely on theoretical grounds. It never even occurred to me to read “most explanatorily powerful theory” as being included in “most scientific theories”. Cool beans.

The only way I can figure out to make D correct using the rules for “and” conditions we’ve learned is to assume that, because it doesn’t address the “benefits the recipient” half of the sufficient, we’re supposed to just assume that part of it is met and for some reason this mom didn’t intend the computer to benefit her daughter, which seems absolutely wild to me. Anyone have any insight on this?

#help

In this video, J.Y. starts and operates with the contrapositive of the conditional rule for arriving at “not generous”. Put into Lawgic straight from the wording with the “unless” indicator, it should read like this:

BR and WMEoCS→G

Contrapositive (which J.Y. is using):

G→ BR or WMEoCS

I LOL’d at J.Y.’s explanation of B and had to rewind in order to listen to it again. His humor is one of the many reasons why I love this curriculum.

I chose C and obviously was unfortunately wrong. Part of my reasoning (in addition to the fact that it doesn’t add anything to the conclusion) for why C is wrong is because of the fact the stimulus states that “Physicists claim”. To claim something doesn’t make it actually true, and thus C doesn’t really add anything when it says that “No system of careful peer review is completely effective in preventing scientific fraud.” C is just being repetitive.

I ended up picking B in BR because I figured maybe the question was aiming in the direction that J.Y. explained. But I’m still not clear on why addressing motivation is not a good method of addressing an argument. This is my thought process: if someone is attempting to sell a product and making claims about it, it usually helps to know whether there is a significant financial incentive driving the sale of said product. The larger the financial incentive, the more tempting it would be to stretch or even falsify the truth regarding the product itself. What am I getting wrong here?

For those still struggling with the conditional diagramming of the second statement as I was:

“If the soil’s nutrients are completely depleted, additional crops cannot be grown unless fertilizer is applied to the soil.”

“If” is a group 1 indicator, “cannot” is a group 4, and “unless” is a group 3. Thus, the Lawgic should read:

CDep→(FA→ACG)

Use what you’ve learned about embedded conditionals and turn it into this:

CDep & FA→ACG

Next, contrapose with Demorgan’s Law:

ACG→FA or CDep

Now the question clears things up so we can look for the right answer; we are told that “some vegetables were grown” (ACG) and that “fertilizer had never been applied” (FA). Since we know now that FA is not possible, we know that a correct answer could be something to do with CDep, which is exactly what C says. Hope this helps someone!

Also, I feel this video needs a second look; the above Lawgic makes much more sense within the bounds of the rules we’ve been taught about conditionals than the one in the video does. I’m interested in understanding how the Lawgic in the video came about at least.

#feedback

Hey Kevin, thanks so much for responding! I think I’m beginning to understand… so would a simpler way to put it be to say that Henry just doesn’t give us more information about what valid explanations he actually accepts, and this is the reason why he doesn’t have an opinion on B?

I’ve really pored over this question and I got it right. My reasoning for choosing C and ruling out B was that, although H sounds like he agrees with B to me (H: “There must therefore be some other explanation for the honeybees’ dance.” sounds like it stands in alignment with B: “There is more than one valid explanation for the dance of honeybees.”), W does not seem to even address the “more than one valid explanation” idea. She is merely addressing the idea of how honeybees communicate food sources.

However, I’m still stuck on why, in the explanation, we’re told that H has no opinion. It seems to me that he does have an opinion; it seems that, per his stated conclusion, he is in agreement that “there is more than one valid explanation for the dance of honeybees”. I’m aware that answer choice B is not addressing how honeybees communicate food sources as well; merely that there could be more than one explanation for the dance. Can anyone help me understand what I’m missing?

I see what you’re saying; don’t bring outside opinions into the test. Thanks!

I’m having a bit of trouble parsing through the last set of conditional statements. I’m attempting to rephrase them into statements with indicators and they get a little fuzzy in terms of which is the sufficient and which is the necessary. For instance:

1. If you are a student who mastered logic, you saw improvements in your PrepTest scores.

Makes sense, but what reasoning prevents one from confusing necessity for sufficiency and saying: “If you saw improvements in your PrepTest scores, you are a student who mastered logic.”? To me this statement seems equally reasonable and makes sense, and yet it confuses necessity and sufficiency. I’m aware that my reasoning is wrong, yet I’m not really sure why. Can anyone help me clarify this?