Logical Appeals in Persuasion

Review: Warrants

• They explain why the grounds prove the point and analyze and summarize the grounds.
• The warrant is the "because" statement.
• When it is evident that the evidence proves the point, it's called the implied warrant.
• Inductive reasoning - working from specific evidence to a general understanding.
• Deductive reasoning - working from a generalized body of evidence to reach a specific example or understanding.
• An error in reasoning is called a fallacy.

Reasoning and their Fallacies
Parallel Reasoning - More often called an analogy, it's used for comparison. Since similar circumstances may have similar outcomes, parallel reasoning leads one to assume or predict outcomes.

• This is used to compare and contrast as well, using what we know to help others understand what they don't
• Parallel reasoning uses literal analogies and figurative analogies.
• Syntax may include like, as, similar, resembles, compared to, by contrast...
• This becomes fallacious reasoning when the analogy is false (false analogy), the apples to oranges mistake.

Examples:

• Employees are like nails. Just as nails must be hit in the head in order to make them work, so must employees.
• Government is like business, so just as business must be sensitive primarily to the bottom line, so also must government. (But the objectives of government and business are completely different, so probably they will have to meet different criteria.)
• Construction workers use blueprints to guide them as they build. Doctors use X-rays and MRI images as diagnostic aids. Therefore, presenters should use PowerPoint slides as teleprompters during live-audience presentations. This argument, of course, is the fallacy of "False Analogy". Why? Blueprints and MRIs are created as visual aids for the construction worker and doctor. A presenter's visual aids are intended for the audience. The comparison, therefore, is invalid.
• Subsidized healthcare is socialism.
  

Generalization - Sometimes drawn from extended parallel reasoning, generalizations involve making predictions, classifications and descriptions. It's also called reasoning by example.

• Generalization is indiscriminitive, reasoning that what is true about one member of a group is true about the rest.
• Syntax includes we have concluded, it is generally so, usually so, normally so...
• This becomes a hasty generalization when there are too few cases counted toward the generalization, so one jumps to conclusions.

Examples:

• All Mormons are polygamists.
• All men are pigs.
• All democrats are tree-huggers.
  

Reasoning by Definition - Breaking down something by what it means, a deductive process.

• Syntax includes it follows that, its necessarily so, so by definition...
• This becomes a sweeping generalization when the definition is too rigid in include relevant exceptions.
• fallacious syntax includes always, never, in every case, certainly, necessarily, categorically...

So, if all men are pigs, and Chris is a man, therefore he must also be a pig.
By that definition that would make me a tree-hugging, post-polygamous swine.


Reasoning by Sign - what I call symptomatic reasoning. Recognizing how artifacts or actions are associate with related events. Summativity v. nonsummativity. Inductive reasoning, very close to causal reasoning.

• Sytnax includes language that deals with factors.
• This becomes a false sign when the link between the indications and the correlating events fails. Supersititions are typical false signs.

Causal or Cause to Effect Reasoning - leads to . Much can go wrong with this type of reasoning.

• A causal link has to be proved with a specific agent of cause.
• Syntax includes causes, leads to, produces, activates, provokes, geneerates, brings about, results in...
• There could be mulitple causation, where the arguer has to sort and prioritize most influential causes.
• However, there can also be unrelated events that contribute to the issue.

There are a number of fallacies related to causal resoning:

• This becomes oversimplification where one ignores other causes, eliminating others to promote their own agenda of cause.
• Correlation v. Causation - connecting two events due to proximity.
• Post hoc ergo propter hoc reasoning, meaning before , therefore because of , just because somehting happened before something else does not mean it is the casue of the outcome.

Example: "I can't help but think that you are the cause of this problem; we never had any problem with the furnace until you moved into the apartment." The manager of the apartment house, on no stated grounds other than the temporal priority of the new tenant's occupancy, has assumed that the tenant's presence has some causal relationship to the furnace's becoming faulty.

• Slippery Slope propses a series of events was caused by one event (the Butterfly effect) without ever showing how it's linked. I had two debaters that no matter what the resolution linked their warrant to total mutual nuclear destruction.

Reasoning from a Dillema - It's the either/or position of reasoning. If you're not for us, you're against us.

• Syntax includes either, or, must choose betwee, pros/cons, costs/gains...
• The fallacy is in forcing the dichotomy, not everything is for or against the proposition. When you make it seem there are only two choices when in fact there are more to consider, you are guilty of forcing the dichotomy.
• The complex question is an example of this when there is a major hidden presumption - Have you stopped beating your wife?

Arguing from Authority - takes an authority's opinion, states their qulifications and then states what the authority said.
Syntax includes in the words of, as was established by, according to, research shows, studies show...
Not all sources are valid authorities.
There's always room to question even the brightrest in the field - QUESTION AUTHORITY
Blind obedience to authority is not cirtical thinking - don't get me started on this.
The fallacy is the appeal to authority, using celebrity to persuade is an example of this - take John Voight for example.