Entry 4_Bùi Thị  Loan

ENTRY 4

Argument Structures and Fallacies

Item 1:

 Source :http://www.nizkor.org/features/fallacies/biased-sample.html

Large scale polls were taken in Florida, California, and Maine and it was found that an average of 55% of those polled spent at least fourteen days a year near the ocean. So, it can be safely concluded that 55% of all Americans spend at least fourteen days near the ocean each year.

Ø  Hasty  Generalization

Analysis :

Premise : an average of 55% of people live in in Florida, California, and Maine spent at least fourteen days a year near the ocean

Conclusion : 55% of all Americans spend at least fourteen days near the ocean each year

Argument error : it is not typical example, so it conducts a true conclusion.

Item 2:

 Source : http://www.nizkor.org/features/fallacies/ignoring-a-common-cause.html

One day Bill wakes up with a fever. A few hours later he finds red spots on his skin. he concludes that the fever must have caused the red spots. His friend insists that the spots and the fever are caused by some microbe. Bill laughs at this and insists that if he spends the day in a tub of cold water his spots will go away.

Ø  Ignoring a Common Cause

Analysis :

Premise 1 :Bill wakes up with a fever

Premise 2 : a few hours later he finds red spots on  his skin.

Conclusion : fever must have caused the red spots

Argument error : the  the causal conclusion is drawn without considering the possibility that a third factor might be the cause of both premise 1 and premise 2.

Item 3:

 Source : http://www.don-lindsay-archive.org/skeptic/arguments.html#jargon

President Dwight Eisenhower expressed astonishment and alarm on discovering that fully half of all Americans had below average intelligence. Similarly, some people get fearful when they learn that their doctor wasn't in the top half of his class. (But that's half of them.)

Ø  Innumeracy

Premise : President Dwight Eisenhower expressed astonishment that fully half of all Americans had below average intelligence.

Conclusion : some people get fearful when they learn that their doctor wasn't in the top half of his class

Argument error : the first evidence doesn’t connect with the conclusion.