Fianna13 wrote:Shinners, can you explain #17 on section 3 on PT 53? I still couldn't figure out why A is right and C is wrong.
Ah, circumstantial evidence. I love the stuff. If only I could finish my Cracked article on why it's so awesome...(this might be the motivation I need).
So this is clearly a flaw question. If I can use a common method of reasoning to describe this argument (in other words, if it was a Describe question), I would call this an argument by analogy. When I have an argument by analogy, and I'm in a flaw question, it's a good bet that my fallacy is a bad comparison/analogy.
So let's look at the analogy here: A body of circumstantial evidence is like a rope. They both have different strands (of evidence, of rope), and you can take some away without affecting the overall strength, according to the lawyer. But is that true of both? For a rope, I know that the strands are fairly equal, but is the same true of evidence?
I would say no. If I have a ton of circumstantial evidence on a defendant, including a piece of circumstantial evidence suggesting he was at the crime scene, then I have a case. But if I take away the circumstantial evidence that he was there (say, I have a video of him somewhere else at the time of the crime), then the whole body of evidence falls apart, no matter how strong the other circumstantial evidence is (unless this is an episode of Monk, in which case the guy probably used some crazy means to kill the person while he was somewhere else; real life doesn't work like that).
So I do, in fact, have a bad analogy here.
A and C are the two answers to be torn between. Let's look at them, and their differences, to see which is correct.
A is exactly what I said before - my body of evidence might be strong, but there might be a critical piece of circumstantial evidence upon which it all rests. Unlike a rope, taking that one strand out might unravel the whole thing.
Now, let's look at C. It says that the argument ignores the possibility that discrediting some items of circumstantial evidence might discredit the entire body of evidence. But does the argument ignore that possibility? No - it takes it into consideration, but decides that it's not the case. It does this by using an analogy. The whole argument seems to be answering the question of whether discrediting a few pieces of evidence destroys the entire body of evidence, and it comes to the conclusion that it doesn't. So it doesn't ignore this possibility; instead, it disagrees with it.