The direct way of reasoning with all...
All S are P
a is S
So a is P
All S are P + a is S = a is P
This argument is valid because it exactly the same as the argument:
All dogs bark.
Marley is a dog.
So Ralph barks.
We all know that all dogs bark and Marley is a dog, then that means that Marley barks.
and for arguing backwards with all...
All S are P
a is P
So a is S
All S are P + a is P = a is S.
This argument would be weak because this argument is like this argument:
All dogs bark.
Marley barks.
So Marley is a dog.
This argument is overlooking possibilities. We do all know that dogs bark, but we can't jump into the conclusion of Marley is a dog even if Marley barks because Marley could be a person trying to play a title of a dog barking or something else.
Saturday, March 26, 2011
Friday, March 25, 2011
Usefulness
To me, the second group assignment was more useful than the first assignment because I got to learn more about the organization, PETA (People for the Ethical Treatment of Animals), that I didn't know that much about it before. PETA creates awareness for animal rights and welfare and rejects any and all forms of animal abuse and cruelty. I enjoyed doing this assignment more because I learned more about how and when to accept and rejecting claims or suspend judgment. You can agree and accept PETA's claims because their claims are based on fact and research and I believe that they have or are the authority when it comes to animal rights and welfare. Yes, I believe that animals shouldn't be hurt and should not suffer but I would also consider it if it involved the welfare of human beings. I also believe that humans need their nutrition from meat and that humans are genetically built to eat meat. In this case, I could suspend judgment since I am a living contradiction of what PETA preaches.
Thursday, March 24, 2011
AllSome
Some people use the word "all" and "some" in their argument sometimes. But not all makes their argument good because they use them wrong.
For example:
All birds fly.
Penguin is one type of bird..
Penguin flies.
This seems valid, but it's not. We all know that penguins don't fly and neither do ostriches which contradics the phrase "all birds fly". So this argument is bad and invalid.
Accorind to Epstein, "All means "Every single one, no exceptions." Sometimes all is meant as "Every single one, and there is at least one." Which reading is best may depend on the argument. And some means "At least one." Sometimes some is as "At least one, but not all." Which reading is best may depend on the argument(Epstein, p.160).
Another example:
Professor Tran requires all his students to use #2 pencil for their exams and students can't take the exam without it.
Becky took Professor Tran's class exam.
Becky used a #2 pencil for the exam.
This argument is valid and good because the word "all" is used properly. We all know that Becky should have not been able to take the exam if she didn't have a #2 pencil to write with on the exam.
For example:
All birds fly.
Penguin is one type of bird..
Penguin flies.
This seems valid, but it's not. We all know that penguins don't fly and neither do ostriches which contradics the phrase "all birds fly". So this argument is bad and invalid.
Accorind to Epstein, "All means "Every single one, no exceptions." Sometimes all is meant as "Every single one, and there is at least one." Which reading is best may depend on the argument. And some means "At least one." Sometimes some is as "At least one, but not all." Which reading is best may depend on the argument(Epstein, p.160).
Another example:
Professor Tran requires all his students to use #2 pencil for their exams and students can't take the exam without it.
Becky took Professor Tran's class exam.
Becky used a #2 pencil for the exam.
This argument is valid and good because the word "all" is used properly. We all know that Becky should have not been able to take the exam if she didn't have a #2 pencil to write with on the exam.
Friday, March 11, 2011
O_O
Using "or" for reasoning with claims can often determine that an argument is valid or weak by looking at the role a compound claim plays in it(Epstein, p. 116).
For example:
Either mom brought the pizza home or dad.
Mom didn't bring the pizza home because she was home all day.
So it must be dad who brought the pizza home.
This argument is valid because there's no possible way for the premises to be true and the conclusion false at the same time.
Another example::
Jade owns a pet. Her pet is either a dog or cat. Her pet is a German Sheperd. So her pet must be a dog.
This argument is valid again because the premises are true and conclusion cant be false at the same time. This is also a strong argument because we all know that her premises are facts and a German Sheperd is a breed of a dog.
For example:
Either mom brought the pizza home or dad.
Mom didn't bring the pizza home because she was home all day.
So it must be dad who brought the pizza home.
This argument is valid because there's no possible way for the premises to be true and the conclusion false at the same time.
Another example::
Jade owns a pet. Her pet is either a dog or cat. Her pet is a German Sheperd. So her pet must be a dog.
This argument is valid again because the premises are true and conclusion cant be false at the same time. This is also a strong argument because we all know that her premises are facts and a German Sheperd is a breed of a dog.
Chapter 7
Refuting an argument is showing that an argument is bad. There are 3 direct ways of refuting an argument: (Epstein, p. 149)
1. Show that at least one of the premises is dubious.
2. Show that the argument isn't valid or strong.
3. Show that the conclusion is false.
And when refuting an argument indirectly, it is sometimes hard to point out a premise that is false or dubious, but you know there's something wrong with the premises. You might get the conclusion that's argued for, but you get a lot more, too-which leads premises to an absurdity(Epstein, p. 149-150).
Reducing to the absurd is to reduce to the absurd is to show that at least one of several claims is false or dubious, or collectively they are unacceptable, by drawing a false or unwanted conclusion from them(Epstein, p. 150). If a valid or strong argument has a false conclusion, one of the premises is false. And if the conclusion is absurd, the premises aren't what you want.
1. Show that at least one of the premises is dubious.
2. Show that the argument isn't valid or strong.
3. Show that the conclusion is false.
And when refuting an argument indirectly, it is sometimes hard to point out a premise that is false or dubious, but you know there's something wrong with the premises. You might get the conclusion that's argued for, but you get a lot more, too-which leads premises to an absurdity(Epstein, p. 149-150).
Reducing to the absurd is to reduce to the absurd is to show that at least one of several claims is false or dubious, or collectively they are unacceptable, by drawing a false or unwanted conclusion from them(Epstein, p. 150). If a valid or strong argument has a false conclusion, one of the premises is false. And if the conclusion is absurd, the premises aren't what you want.
Thursday, March 10, 2011
Chapter 6
Chapter 6 in the Epstein text, I learned about compound claims and "or" claims. A compound claim is a one composed of other claims, but which hasto be viewed as just one claim(Epstein, p.113).
For example: "I'll take you out to eat at Red Robin or I'll take you out to the movies."
I didn't promise to take you out to eat at Red Robin nor take you out to the movies. I promised to do one or the other. This is considered as one claim, not two. If I used the word "and" instead of "or", then we would have two claims - "I'll take you out to eat at Red Robin" and I'll take you out to the movies".
Another lesson I learned from chapter 6 is the contradictory of a claim. The contracditory of a claim is one htath as the opposite truth-value in all possible circumtances. Sometimes a contradictory is called the negation of a claim(Epstein, p. 114).
Example:
Claim: I am allergic to alcohol.
Contradictory: I am not allergic to alcohol.
For example: "I'll take you out to eat at Red Robin or I'll take you out to the movies."
I didn't promise to take you out to eat at Red Robin nor take you out to the movies. I promised to do one or the other. This is considered as one claim, not two. If I used the word "and" instead of "or", then we would have two claims - "I'll take you out to eat at Red Robin" and I'll take you out to the movies".
Another lesson I learned from chapter 6 is the contradictory of a claim. The contracditory of a claim is one htath as the opposite truth-value in all possible circumtances. Sometimes a contradictory is called the negation of a claim(Epstein, p. 114).
Example:
Claim: I am allergic to alcohol.
Contradictory: I am not allergic to alcohol.
Friday, March 4, 2011
Inferring and Implying
"Inferring is when you decide that an unstated claim is the conclusion. And implying is when someone leaves a conclusion unsaid." (Epstein, p.74)
For example: Suppose a teacher says in math class, "All of my best students go to workshops for extra credit." The teacher hasn't actually said you should in extra work. But you infer that she has implied "If you want to do well in this class, you'd better go to workshops for extra credit."
Implying and inferring could be risky because of you complain to the department head that your teacher is demanding more than she asked on the syllabus, your teacher could reply that you just inferred incorrectly. The teacher might say, "I've observed that my best students do extra-credit work - that's all I was saying. I had no intention of making an argument." You, however, could say that in the context in which she made the remark it was fairly obvious she was implying that if you wanted her to believe you are a good student, you should go to workshops.
This example is really the same as the example from the book. (Epstein, p.74)
For example: Suppose a teacher says in math class, "All of my best students go to workshops for extra credit." The teacher hasn't actually said you should in extra work. But you infer that she has implied "If you want to do well in this class, you'd better go to workshops for extra credit."
Implying and inferring could be risky because of you complain to the department head that your teacher is demanding more than she asked on the syllabus, your teacher could reply that you just inferred incorrectly. The teacher might say, "I've observed that my best students do extra-credit work - that's all I was saying. I had no intention of making an argument." You, however, could say that in the context in which she made the remark it was fairly obvious she was implying that if you wanted her to believe you are a good student, you should go to workshops.
This example is really the same as the example from the book. (Epstein, p.74)
Advertising
http://www.karmaloop.com/index-new.aspx
Receiving emails from the store people buy things from about deals excite people because this give them the chance to save money due to getting good deals. Free shipping is one of the best deals we could get when we shop online. I just visited www.karmaloop.com, the online store I always buy my clothes from and found that they are giving a free shipping on orders over $50 by using the code 50SHIP. Either you buy new arrival items or sale items, you will get the free shipping as long as your order costs over $50.
Karmaloop also gives exclusive deals to people who sign up to represent karmaloop, like myself, by sending them emails. For example, I got an email about a deal that gives me 20% off on MENS REGULAR priced items only.
Receiving emails from the store people buy things from about deals excite people because this give them the chance to save money due to getting good deals. Free shipping is one of the best deals we could get when we shop online. I just visited www.karmaloop.com, the online store I always buy my clothes from and found that they are giving a free shipping on orders over $50 by using the code 50SHIP. Either you buy new arrival items or sale items, you will get the free shipping as long as your order costs over $50.
Karmaloop also gives exclusive deals to people who sign up to represent karmaloop, like myself, by sending them emails. For example, I got an email about a deal that gives me 20% off on MENS REGULAR priced items only.
Based on my personal experience, this source is reliable because all the given statements are facts. I get almost all of my clothes from this site and I have never had a problem with them. If you happen to have a problem with sizes or anything, you can contact them and tell them what the problem is and they will help you out. Also, “the claim is in a media source that’s usually reliable and has no obvious motive to mislead, and the original source is named” (Epstein, p.90).
Thursday, March 3, 2011
FIX IT!
Argument: All fishes swim. Therefore, Nemo swims.
This argument would be valid or strong argument if it will be repaired. Even if all fishes swims and concluding that Nemo swims without stating that Nemo is a fish, that argument wouldn't make any sense because Nemo could be anything. So, this argument needs to repaired in order for it to be a valid or strong argument.
To fix this, "Nemo is a fish" should be added because it is the only premise that will make this a valid or strong argument. Adding this true premise will make the argument good.
Repaired statement would be:
All fishes swim. Nemo is a fish. Therefore, Nemo swims.
Stating Nemo is a fish would give "Nemo swims" more sense. It makes the argument a valid and strong argument. Without the premise "Nemo is a fish", the argument would not make sense at all and ends up as a invalid argument.
This argument would be valid or strong argument if it will be repaired. Even if all fishes swims and concluding that Nemo swims without stating that Nemo is a fish, that argument wouldn't make any sense because Nemo could be anything. So, this argument needs to repaired in order for it to be a valid or strong argument.
To fix this, "Nemo is a fish" should be added because it is the only premise that will make this a valid or strong argument. Adding this true premise will make the argument good.
Repaired statement would be:
All fishes swim. Nemo is a fish. Therefore, Nemo swims.
Stating Nemo is a fish would give "Nemo swims" more sense. It makes the argument a valid and strong argument. Without the premise "Nemo is a fish", the argument would not make sense at all and ends up as a invalid argument.
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