communicationstudies

• Insufficient or inadequate information poses the greatest threat to the integrity of an argument, but even with adequate material to support it an argument can fail because of structural weaknesses and counterfeit strategies
• Suppressed, ignored, or unconsidered evidence can invalidate conclusions
• Try to identify the assumptions on which your argument rests, and consider whether your evidence adequately supports your conclusions
• Anticipate possible counter-arguments or objections to your methods
• Treat your own argument as you would an opponent's, checking for every possible weakness, every advantageous point of attack
• Look for failures in logic; challenge your own assumptions
• Be aware of the common fallacies in reasoning
• Non sequitur


  An illogical statement, one that seems to draw a conclusion not supported by the premises
• Non sequitur


  • Education is the only way to combat unemployment
  • My essay will get a good grade because I put a lot of effort into it
• Often a statement appears to be a non sequitur because the writer has failed to include the assumptions that establish connections between ideas
• Ad hominem


  An argument that evades the task of addressing the question and instead appeals to the feelings of the audience
• Ad hominem

  • Clinton's infidelity to his wife invalidates his Mideast peace policy
• Appeal to Authority (argumentum ad verecundiam)

  Inappropriate appeals to authority that depend upon the substitution of a famous name for a serious argument
• Appeal to Authority


  • Drink Vichy water; Paris Hilton does
• False Analogy


  An assertion that because a similarity exists in one aspect, it must also exist in other aspects
• False Analogy


  • Defending his rationale for pursuing the Vietnam War, president Lyndon Johnson said, "We learned from Hitler at Munich that success only feeds the appetite of aggression."
• Bandwagon Argument (argumentum ad populum)


  An argument that appeals to the beliefs or prejudices of the crowd
• Bandwagon Argument


  • Jim MacPherson should be treasurer; as everyone knows, the Scots are naturally thrifty
  • Everyone believes Martin's ideas are stupid; Martin must be wrong
  • Drink this soda pop; it is the choice of a new generation
• Begging the Question (petitio principii) / Circular Reasoning


  Treating matters under debate as already established
• Begging the Question


  • The reason radiography was not discovered sooner was that men whose business it was to discover new clinical methods were coarsening and stupefying themselves with the sensual villainies of vivisection
  • We must carefully identify these promoters of hatred so that they can be removed from positions in the public services
• Circular Reasoning


  • Clearly, Mary is failing the class because she cannot manage to achieve at the level required to pass
  • Sky-diving is dangerous because it is characterized by extreme risks
  • Marxist materialism provides the only sound critique of society because, without the perspective of the economic determination of all social actions and institutions, no valid commentary is possible
• False Dichotomy ("either...or" fallacy)


  The fallacious presentation of two possibilities as the only possibilities
• False Dichotomy


  • Either the government will silence dissenting voices or it will face anarchy
  • I must pass Calculus, or my life will be ruined
  • Citizens must choose between supporting gun control and supporting murder
• Hasty Generalization


  Making poor arguments by relying upon a non-exhaustive body of evidence
• In most situations, it will be difficult to limit the possibilities to a manageable half-dozen, let alone two
• Hasty generalization


  Generalizations that make poor arguments because they rely upon a non-exhaustive body of evidence
• Generalizations may well be right most of the time, but they are also wrong some of the time</b>
• Generalizations are usually not supported by specific information but by an appeal to common sense or common experience
• Generalizations present as general and absolute something that is limited and contingent
• Arguments are often based on anecdotal evidence on specific, undocumented case histories
• Exploration of areas where better evidence is not available is exciting, but it is sometimes mistaken for coherent argument
• Post hoc, ergo propter hoc


  Assuming that sequence indicates causation, when many things happen in succession without any direct connection
• Cum hoc, ergo propter hoc

  Assuming that accompaniment indicates causation, when correlations are not proofs but rather indications of areas ripe with research possibilities
• Reductio ad absurdum


  A legitimate tool that works by discovering a contradiction in a proposition opposite to one under discussion, thus proving the original proposition must be true
• Reductio ad absurdum can also be used more loosely to pursue a proposition to a point at which it is contradicted either internally or empirically
• Red herring


  A statement introducing an unrelated point instead of addressing the question under debate
• Argument from ignorance


  Assuming that because something has not been proven false, it is therefore true, or that because something has not been proven true, it must therefore be false
• Emotionalism


  Using feelings or ungrounded opinions to corrupt logic, rather than making a logical argument
• The legal value of emotion is increasingly important, as a victim's perceptions or feelings may be good and sufficient evidence of someone else's misconduct
• In the perfect laboratory of formal, written argument, logic is always in demand, even for those who plan to conduct their arguments principally on emotional grounds