Flow charts for analyzing Empirical Premises

Longview Community College, Lee's Summit, Missouri

Critical Thinking
Across the
Curriculum Project

Flow Charts for Evaluating Arguments: Part III

Contributed by Michael Connelly, Longview Community College.

Except for those premises which describe a particular state of affairs, Empirical Premises are usually the conclusion of an Inductive argument. The exact nature of these arguments will determine how we go about assessing the truth value of the premise in question. One of the first steps in analyzing an Empirical Premise is to determine what sort of statement it is:

Flow Chart for Verifying Claims about Particular Instances:

Claims which involve descriptions of Particular Instances can be verified by the use of Direct Observation - we look to see if the instance actually occured. In some cases, however, we are unable to directly observe the instance ourselves, and will have to rely on the Testimony of others. Often this testimony is combined with Photographs or Videotape to attempt to bolster the testimonial evidence. With the advance of digital photography and special effects, these sources carry much less weight than they used to. For example, Photographs can no longer be used as evidence in many court cases because of the ease with which they can be doctored (like the photo of Bill Clinton with the space alien). Likewise, video footage can also be doctored or even staged to 'witness' to an event which actually did not happen (for example, NBC's rigging of a Chevy pickup to explode on impact). In order to determine the truth of a premise which refers to a particular instance, the following questions must be asked:

You are lucky! Be wary of the illusions and tricks described above.

If there are a significant number of people who report the particular instance being claimed, then it is more likely that the event actually occured (barring some mass hallucination or conspiracy) But, if only one or two witness it, then other factors must be considered.

Parents use this step all of the time - if the stories do not match up, then one of the reporters is probably not telling the truth. On the other hand, if all of the reports of the particular instance are in close agreement, then it is more likely that the event happened as the reporters described it.

Who do you believe, the Washington Post or the National Enquirer? A trusted friend or a total stranger who is trying to sell you something? If the person giving the report has something to gain by your believing it, then it is wise to be suspicious of the report.

If the statement describing a particular instance or event has been reported by a number of reliable people (those with nothing to gain by lying) whose reports pretty much agree, then it is likely that the statement describing the event or instance is true. Remember, though, that even with these assurances it is still possible for the statement to be false - masses of trustworthy people have been wrong before! Premises which do not describe a particular instance will require a bit more in the way of analysis.

In the scientific realm, a particular instance can be verified by repetition. This is the reason researchers are supposed to keep good lab records. If an experiment yields a particular result, that result should be able to be reproduced in another experiment by following the exact sequence of events recorded in the Lab notes. (If there is something missing, then we have a problem - the experiment is not reproducible.) If the result cannot be duplicated in another experiment, then that result is cast into doubt. A disturbing trend in research recently has been the reluctance of the Principal Investigator to request a re-do on an experiment. Even those experiments which seem to have 'significant' results for a particular field are not duplicated to check the results - in fact, some researchers consider it an insult to be asked to repeat research. This is detrimental to science - any experiment with results important enough to be labled 'significant' by a research lab ought to be repeated to insure credibility - remember, the more instances of the occurance, the more credible the claims associated with it.

Inductive arguments: Which type is it?

When trying to assess the truth value of premises which are the result of an inductive argument, we first have to determine which type of argument is being appealed to in establishing the probable truth of the premise. The first type is an argument by analogy, the second is a generalization which moves from a set of particular instances to a General statement (moving from the particular to the general), and the third is a generalization which begins with a general statement and applies it to a particular instance. Here are some examples:

Argument by Analogy: When asked by the press why he would not criticize the president, the leader of a political party replied; "You don't tackle the quarterback of your own team, do you?".
Particular to General: Every time I have set off a spark near a pool of gasoline, the gas has ignited. Thus, gasoline must be flammable.
General to Particular: The average life span of dogs of this breed is 17 years, thus, my dog muffy (who is of this breed) will live for 17 years.

Arguments of the second type and third type often involve Causal arguments or Statistical arguments, each of which will have to be analyzed by different methods. Arguments of the first type involve Arguments by Analogy, which will require their own methods of analysis. Hence, we will need at least three different flow charts. These will be divided by the types of arguments involved.

Copyright © 1996
Critical Thinking Across the Curriculum Project
Longview Community College , Lee's Summit, Missouri - U.S.A.
One of the Metropolitan Community Colleges
An Equal Opportunity/Affirmative Action Employer

Permission to reproduce these resource pages is granted for
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Inquiries to: michael.connelly@kcmetro.edu
Last modified: 03/02/04