PT50, S2, Q10 - Recently, the city council passed

[dj_grey]

I did this problem the first time and selected as my answer E.

Came back to this problem a 2nd time (after some time) and again i selected E.

I know the answer is B but i just dont see the logic. Can somone help?

I mean i see why B could be the answer..........i just dont see why E cant.

[bradleygirard]

Perhaps I am totally wrong on this one, but here goes anyway. Answer E says that the argument treats a necessary condition for achieving the goals as a sufficient condition. Lets see if we can diagram that.
If the necessary condition for achieving the goal (lets call it RL for reduced loitering) is an Ordinance (O), then the diagram would be thus.
RL-->O "If we are going to reduce loitering then we must have an ordinance."

Now if the argument switched those two as it says in E, it would read;
O-->RL "If we are going to have an ordinance then it must be the goal to reduce loitering."

This is actually the opposite of what E does. E doesnt posit the goal as a necessary condition, but rather attacks the goal as not being as such, because it wont work.
An argument that would actually fit E would be one such as, "recently the city council passed the ordinance with the goal of banning loitering. This was wrong because now we cannot pass any ordinance that doesnt ban loitering" or something ridiculous to that effect.
hope it helps.

[bbirdwell]

Hey guys,

Bradley, great effort in trying to make a necessary/sufficient example out of this. It's hard to do because there isn't any necessary/sufficient logic in the original argument!

The argument simply says:
The goal of the ordinance was to eliminate overcrowding and alleviate pedestrian congestion.

The author concludes:
This is not the goal of the ordinance! Why? Because the ordinance is ineffective at doing that!

So what's the flaw in the logic? Nothing fancy. Just because a certain idea is ineffective at achieving a result, does this mean that achieving the result is not a goal of the idea??

This is what (B) says.

This is an example of an argument that simply doesn't lend itself to conditional diagramming, and thus necessary/sufficient should not even be on your radar. You don't have to dig into the details of (E) because it doesn't even apply on the surface...

Here's another way of thinking about the argument:
Bob says he's drinking green tea in an attempt to gain weight. This can't be his real goal, though, because drinking green tea will never lead to gaining weight.

Sure, Bob might be wrong about green tea, but that doesn't mean he's lying about his goal.

[bradleygirard]

I guess I just cant get away from conditional reasoning, no matter how hard I try.

[bbirdwell]

That's a good instinct! You should continue to do that!

In a sense, one could make the conclusion conditional:

~effective --> ~goal
goal --> effective

But it doesn't rest on any conditional premises, so this isn't of much use.

Keep it up! Most of the time, attempting to symbolize arguments in this way is the only correct approach.