Definition: using a reformulation of an opinion as justification for that opinion.
Example: A good person is someone who does good things. If I do good things, then I am a good person.

Definition: Latin for "It doesn't follow" - draw conclusions that are not correct because the conclusion does not follow or is illogical.
Example: We make good decisions because we have been right in the past. "The boys in my class are better at science than most of the girls I teach. I wonder which boy is going to win the science fair this year."

Definition:After the fact, therefore because of the fact - observing that because one event follows another we commit the error of supposing that one event is the cause of the other event.
Example:The last time I went to the dentist he found a cavity. The previous time I went to the dentist I also had to have a filling for a cavity. I am not going back to that dentist because I know he will find another cavity.

Definition:Circumstantial evidence assumes evidence to be causally related. Attempts to prove a position are made by means of inference.
Example: From the evidence that a person was seen running away from the scene of a crime, a judge or jury may infer that the person committed the crime.

Definition: The unnecessary limiting of choices. Presenting only two possible alternatives when others may be justified.
Example:Either Creationism is true or Darwin's Theory of Evolution must be true. Therefore, if it is shown that Darwin's theory is false, then Creationism must be true.

Definition: The intentional falsification of the truth. Lying that occurs as an argument's premise is known as "questionable premise".
Example: "The official language of the United States was, is, and always will be English".

Definition:Drawing parallels while ignoring pertinent differences in order to make an argument.
Example: When Americans act together, we are as powerful as the ocean's tides.

Definition: Quoting someone, but selecting only a portion of the quote, which is available, and therefore the person's arguments are distorted when taken "out of context".
Example: (1) Charles Darwin. The first portion has been frequently printed without using the full quote to question the validity of the theory of evolution.

"To suppose that the eye with all its inimitable contrivances for adjusting the focus to different distances, for admitting different amounts of light, and for the correction of spherical and chromatic aberration, could have been formed by natural selection seems, I freely confess, absurd in the highest degree."

Here is the rest of the quote that has been omitted.

"Yet reason tells me, that if numerous gradations from a perfect and complex eye to one very imperfect and simple, each grade being useful to its possessor, can be shown to exist; if further, the eye does vary ever so slightly, and the variations be inherited, which is certainly the case; and if any variation or modification in the organ be ever useful to an animal under changing conditions of life, then the difficulty of believing that a perfect and complex eye could be formed by natural selection, though insuperable by our imagination, can hardly be considered real. How a nerve comes to be sensitive to light, hardly concerns us more than how life itself first originated; but I may remark that several facts make me suspect that any sensitive nerve may be rendered sensitive to light, and likewise to those coarser vibrations of the air which is sound."

Definition: Relying on authority to the exclusion of logic and facts.
Example: I started on the "North Beach Diet" this past weekend. I read in the newspaper that I can loose 5 pounds a week.

Definition: Making an assumption beyond what the facts permit.
Example: Mr. Lewis, the sixth grade teacher, makes the whole class stay 20 minutes after school if they do not get quiet before the bell rings. His students are the best behaved students in the school. I am going to do the same thing starting on Monday.

Definition: Any fallacy based on the misuse of statistics that makes the argument appear to be legitimate because it is supported by the weight of science.
Example: The past five years have been exciting for our city. We have experience a 25% growth in the population. During this period we built 5 new schools. We have also worked hard to improve student's performance in basic subjects such as reading and math. We have determined that there was a 10% increase in the number of students who scored in the 80 percentile after we implemented our new reading program.
The problem with this line of reasoning is that there were more students in the district because of a 25% growth in the population of the city during the period reviewed. Under this scenario it is possible that the average student performance went down as a result of the reading program.

Definition: The technique where the best theory, despite flaws, needs to be accepted because no current alternatives appear viable.
Example: String theory still has holes but it is the only theory that enables us to offer a unified theory of the universe.

Definition: When making an unusual claim, the burden is on the person making the claim. Shifting the burden of proof occurs when the responsibility to prove a claim is shifted to the opponent to disprove it.
Example: "Saddam Hussein had weapons of mass destruction. All of our prewar intelligence led us to the conclusion that he had the weapons. Where is your proof that he didn't hide them and they are still in Iraq or Syria?"

Definition: Disqualifying an argument by its own premise.
Example: The market works best when left to itself; in this way we get the best results. Socialized medicine of Canada cannot produce a medical system as effective as we have in America because the free market isn't allowed to function in Canadian medicine.

Definition: Attacking the opponent instead of his argument with the intent of creating unfavorable opinion of the person. Ad Hominem are intended to discredit the person and not the argument.
Example: Jack is untrustworthy when he argues that we need the death penalty because he is a convicted felon.

Definition: Avoiding the issue or question; changing the subject;
Example: Question: Will the Oakland A's be in first place if they win tomorrow's game?

Answer: What makes you think they'll win tomorrow's game?

Definition: Leading the argument off in a wrong direction and avoiding a relevant discussion of the issues.
Example: If we accept Personal Savings Accounts it will be the ruin of Social Security. The little guy always gets it in the end. The President of the company is making millions while the hourly worker is making pennies.

The issue of wages is a red herring to the argument of what's best for Social Security

Definition: Confusing the argument by switching or shifting the definitions of terms.
Example: Those protestors are up in arms about racism because they believe that discrimination is wrong. The fact is they discriminate all the time. They discriminate when they choose shows they like on TV. We all discriminate everyday.

The word "discrimination" changes its meaning during the argument.

Definition: Selecting an easy position to attack even if the opponent does not subscribe to that position.
Example: Opponent: There is no doubt that our schools are failing. My opponent, the senator, voted against the education bill last year that would have given each student in our schools text books and qualified teachers.

The opponent has twisted what the senator did thus creating a straw man. The senator actually voted down the bill because it was above the established spending limits and provided raises for teacher salaries.

Definition: Listing all the points in your favor while ignoring everything else
Example: The transportation manager made a recommendation for using a specific trucking company based on the company's reliability, cost, and references from four other companies.

Unfortunately, the manager did not choose to tell his boss that his brother runs the trucking company, thus creating a conflict of interest.

Definition: The person is made to look guilty because of the people or group he/she associates with
Example: Jimmy and Ben are best friends. Ben got caught cheating on his final. It is obvious that Jimmy also cheated because he got an A on the final.

Definition: Decisions taken speedily before all of evidence has been presented.
Example: He didn't return my phone call. What did I do?

Definition: Diverting attention from an issue with a quick joke.
Example: William Jennings Bryan at the Scopes Trial responded to Clarence Darrow's question "Do you know how old this rock is?" with, "I'm more interested in the Rock of Ages than the age of rocks!"

Definition: Appealing to someone based on how something has been done in the past, implying that if it was a good idea then it must be a good idea now.
Example: Our legislatures should retain the right to filibuster. We have always done it that way and to change now would begin the disintegration of our form of government.

The advisability of retaining the use of the filibuster may or may not be a good practice for our legislature, but the real issue is what is working and what isn't regarding this system.