Logic can be defined as the study of argumentation.

Logic can be defined as the study of argumentation. By argumentation, we mean the
presentation of evidence and premises in order to draw a conclusion. For example, "That
man just came into this room from outside the building. He is soaking wet. People only
get wet like that if they get caught in a rainshower. Therefore, it must be raining outside."
This simple conclusion is based upon evidence -- the man is wet -- and a premise -- one
would not normally be soaking wet unless one were caught in a rainshower. The evidence
comes from one's eyes, but the premise is more interesting. One can think of other ways
the man could have gotten wet. So is it safe to draw the conclusion? This is what logical
analysis studies.
Now I want you to try it. Run through the following premise spotting exercise. The first
thing you must do is to separate the evidence from the premise(s). Then figure out what
the conclusion is. Finally, you must ask yourself if the premises lead to the conclusion.
But before you pass judgment on the conclusion, make sure that you have all of the
premises. Many times, a premise will be hidden. Sometimes evidence is hidden.
For example, "There is going to be a war. Russia and France have both moved two tank
divisions each to the Polish border." The evidence is the movement of the tank divisions.
But what is the premise?
The answer is something like, "Every time Russia and France move troops to the border
of Poland, they try to invade it." Or it might be, "The only reason that any nation would
have for amassing troops on the border of Poland would be to invade it."
The first premise is based upon further evidence -- the history of Russia and France. The
second is an assumption about the purpose and use of tanks.
By determining what the premises are, you are able to question the validity of the
conclusion.
Now you try it in the journal. Each premise spotting exercise is worth three points.

1. “All segregation statutes are unjust because segregation
distorts the soul and damages the personality.” (source: Martin
Luther King Jr., “Letter from Birmingham Jail,” 1963)
2. “Genes and proteins are discovered, not invented.
Inventions are patentable, discoveries are not. Thus protein
patents are intrinsically flawed.” (source: Daniel Alroy,
“Invention vs. Discovery,” The New York Times, March 29,
2000)
3. “We must have filters on our library computers. Our public
library must not be used to channel porn. (Ann Arbor News,”
February 3, 2004)

4. “Democracy has at least one merit, namely, that a member
of Parliament cannot be stupider than his constituents, for the
more stupid he is, the more stupid they were to elect him.”
(source: Bertrand Russell, “Autobiography,” 1967)
5. “Twenty-eight children in the United States were killed by
falling television sets between 1990 and 1997. That is four
times as many people as were killed by great white shark
attacks in the twentieth century. Loosely speaking, this means
that watching ‘Jaws’ on TV is more dangerous than swimming
in the Pacific. (New York Times, 11/6/ 2001)
6. “It is a capital mistake to theorize before one has data.
Insensibly one begins to twist facts to suit theories, instead of
theories to suit facts.” (source: Sherlock Holmes in Arthur
Conan Doyle’s “A Scandal in Bohemia,” 1891)
7. "One of the fastest ways to put America back to work,
Republicans believe, is to limit the regulatory expenses that
small firms have to comply with, simply to satisfy federal
government regulations," said Sessions. "Regulatory burdens
are hindering job growth." In his memo, Cantor targets 10 new
or proposed regulations. Seven of them take aim at the
Environmental Protection Agency — everything from blocking
tougher ozone standards to delaying new anti-pollution
equipment requirements for power plants, boilers and cement
makers.
8. Kobe Bryant should’ve won the Most Valuable Player award
for 2005-06, because he scored more points than any other
player.
9. Mr. Smith’s fingerprints were found on the weapon that
killed Mr. Jones. Furthermore, no other fingerprints were found
on the weapon. Therefore, Mr. Smith killed Mr. Jones.
10. The exercise, training and development of our powers of
discriminating among works of art are plainly aesthetic
activities. Therefore, the aesthetic qualities of a picture plainly
include those that determine how it is to be looked at.