To develop a logical argument, one must draw reasonable conclusions from evidence and recognize fallacies in thinking. Fallacies are faulty or illogical arguments that can undermine writing if not avoided. Some common fallacies include appealing to ignorance by arguing a claim is true because it hasn't been proven false, appealing to pity to gain sympathy rather than support an argument with evidence, and oversimplifying complex issues by reducing them to single causes. Careful reasoning and avoiding fallacious thinking are important for developing convincing arguments.

1. To develop an effective, convincing argument, you must think and write logically. You
must draw reasonable and sensible conclusions from solid evidence. Furthermore, you
must be able to recognize and avoid fallacies of thinking, or false arguments, in your
work. By fallacies, we mean the baits of fuzzy or illogical thinking that may crop up in
your writing if you are not careful. (They also crop up in advertisements, political
appeals, and such.)
Fallacies of Thinking
Appeal to Ignorance The fallacy that a proposition is true simply on the basis that it
has not been proved false or that it is false simply because it has
not been proved true. This error in reasoning is often expressed
with influential rhetoric.
Show me one study that proves cigarettes lead to heart disease.
Appeal to Pity A fallacy in which someone tries to win support for an
argument or idea by exploiting her or his opponent's feelings of
pity or guilt.
Student: “May I have an extension on this paper? I worked on it
all weekend, but it’s still not done.
Bandwagon A fallacy in which a threat of rejection by one's peers (or peer
pressure) is substituted for evidence in an "argument."
Everyone walked out of the meeting. It was the smartest thing
to do.
Broad Generalization Takes in everything and everyone at once, allowing no
exceptions. Example: College students can’t manage money.
College students can’t manage money.
Either-Or Thinking Consists of reducing a solution to two possible extremes:
“America: Love It or Leave It.” “Put up or shut up.” Eliminates
the middle thinking ground.
Either this community provides light-rail transportation, or it
will be impossible to expand in the future.
Half Truths Contains part of the truth but not the whole truth. They are
especially misleading because they leave out “the rest of the
story.” True and dishonest at the same time.
The new welfare bill is good because it will get people off the
public dole. (Maybe so, but it may also cause undue suffering
to some truly needy individuals.)
Oversimplifications “It all boils down to..” or “It’s a simple question of..” are
examples of phrases used in oversimplifications. Nothing
comes down to just one thing.

2. Capital punishment is a simple question of protecting society.
Slanted Language Choosing words that carry strong positive or negative feelings, a
person can distract the audience, leading them away from the
valid argument being made.
I am firm. You are obstinate. He is pigheaded.
Testimonial If the testimonial of statement comes from a recognized
authority in the field, great. If it comes from a famous person in
another field, beware.
Sports hero: “I’ve tried every cold medicine on the market, and
–believe me—nothing worlds like Temptrol.”