I got 100% on the logic test. I'm a little proud of myself.
15 is definitely tricky, I basically decided that to go along the lines that just because we have observed it as it is in the past, we can't necessarily predict what will be observed in the future.
Also its -13℃ in Rochester right now. Wind chill has it feeling like -23℃. I'm happy I don't have to go outside today.
53%. I figured that "valid" meant "correct". But I got both the murder question (too much playing Phoenix Wright) and the last philosophical question (I figured you couldn't take any sample of water and expect finding just hydrogen and oxygen in there) right.
In this example, you can just ignore 1) and 2). All they are asking for is the validity or invalidity of the conclusion statement. The numbered items are simply assumed truths in the same universe as the conclusion. They do not necessarily have anything to do with the conclusion.
Sorry Scott, but you are full of it. At least one of the premises has to to have something to do with the conclusion, or it wouldn't be a test of deductive logic. Even in your own example you have to use 3). By your above logic question 9:
a) Blue and yellow make green. b) Blue and red make brown.
Conclusion Therefore blue and white make sky blue.
would be valid. This is not so. Furthermore, since you claim to only have gotten question 15 wrong, you clearly understand this. I accuse you thus of talking out of your ass and flawed reasoning.
Even if they had written, as you suggest:
Therefore it would be logical to conclude that every future examination of water will reveal the same chemical composition.
This would still be invalid as the "examination" in the conclusion may be something other than the "examination by microscope" mentioned in the premise. Indeed, I can think of several ways to examine water that yield no information about it's chemical composition.
I just took a Logic course last semester and question 15 is one of the first things we learned.
If something cannot be proven false, it is a valid argument. 1+1=2 is valid. "The sun will rise tomorrow, because it has everyday before it" is invalid.
I got Q15 wrong because I define water as 2 hydrogen atoms and 1 oxygen atom. So, obviously every examination of water (H2O) would show 2 hydrogen atoms and 1 oxygen atom. If it doesn't, you aren't examining water.
Just a note when Rym and Scott were talking about using acid to dispose of a body. The enamel on human teeth cannot be destroyed by acid. However, an alternative is to pull the teeth out of the skull, crush them up and mix them with some bird seed. Then go to the park and feed the pigeons with it.
Just a note when Rym and Scott were talking about using acid to dispose of a body. The enamel on human teeth cannot be destroyed by acid. However, an alternative is to pull the teeth out of the skull, crush them up and mix them with some bird seed. Then go to the park and feed the pigeons with it.
The thing is you aren't trying to dispose of a body. You are pretending to die in a way in which a dead certificate will be issued without anyone finding a body.
If people believe that you fell into a vat of acid, and nobody finds your body, you will be presumed dead. Someone would have to know that your teeth would be in there, and they would have to look for them. Even if they looked for them, there is a chance they just assume they can't find them, or that maybe the acid was strong enough to get them.
If you're actually trying to dispose of a body, because you are a murderer, pigs are the way to go.
Speaking of arguing the case for the last question in the logic quiz (which I discovered some days before this episode, amusingly enough) I actually wrote to the author about my interpretation of the last question. He was kind enough to reply.
The answer given on the web site is, as you say, incorrect and needs adjusting, but then it would not be controversial and I would probably not get any feedback.
I like that way of looking at it.
The syllogism itself is invalid and can only be considered as a strong inductive argument and not deductive. It is the 'we can predict' part of the conclusion which comes from nowhere, so the argument is not strictly formal. Not everyone agrees with this so I will leave you to draw your own conclusions. I discuss these points in my book if I may put in a plug!
So there we go. Scott and I are right, the question's at fault.
I got 80% and feel slightly dopey about it. Got questions 3, 14 & 15 wrong, I understand where I went wrong through in each one, so hopefully it'll help improve my logic for the future.
Comments
15 is definitely tricky, I basically decided that to go along the lines that just because we have observed it as it is in the past, we can't necessarily predict what will be observed in the future.
Also its -13℃ in Rochester right now. Wind chill has it feeling like -23℃. I'm happy I don't have to go outside today.
I should be wearing shorts right now.
Question 15 is still bullshit.
Even if they had written, as you suggest: This would still be invalid as the "examination" in the conclusion may be something other than the "examination by microscope" mentioned in the premise. Indeed, I can think of several ways to examine water that yield no information about it's chemical composition.
I just took a Logic course last semester and question 15 is one of the first things we learned.
If something cannot be proven false, it is a valid argument. 1+1=2 is valid. "The sun will rise tomorrow, because it has everyday before it" is invalid.
If people believe that you fell into a vat of acid, and nobody finds your body, you will be presumed dead. Someone would have to know that your teeth would be in there, and they would have to look for them. Even if they looked for them, there is a chance they just assume they can't find them, or that maybe the acid was strong enough to get them.
If you're actually trying to dispose of a body, because you are a murderer, pigs are the way to go.
There are some words that you have managed to sneak into my vocabulary. "Fuck" (for this specific sense) is now one of them.
And yes, at 3:43 (tee hee, 7^3) am, it is fuck outside.
EDIT: Woops. I got distracted by the internet for 20 minutes before pushing the "post" button.