Avoiding Fallacious Reasoning: Lesson 3

Quick Review

Enter in the correct fallacy

?Drawing a conclusion about a whole group, or class, of things based on an inadequate sample of the group|Hasty generalization

?Assigning two different meanings to the same word in an argument|equivocation

?The misrepresentation of a person’s views so he or she can be more easily attacked or dismissed|Straw man

?Rejecting a statement on the grounds that it comes from a particular person, not because the statement, or claim, itself is false or dubious|ad hominem

?Arguing that merely because a claim is sanctioned by tradition, it must be true|appeal to tradition

?Arguing erroneously that a particular action should not be taken because it will lead inevitably to other actions resulting in some dire outcome|slippery slope

?Arguing erroneously that what can be said of the whole can be said of the parts|Division

?Arguing that a statement can be judged true or false based on its source|genetic

?Arguing erroneously that what can be said of the parts can be said of the whole|Composition

?Arguing that a claim must be true not because it is backed by good reasons but simply because many people believe it|ad populum

Chapter 2: How to Read an Argument

Chapter 2 deals primarily with inductive and deductive arguments. I’ll use Kreef’s text on Socratic Logic to introduce how inductive and deductive arguments tie in with each other.

Example using the Socratic method from Kreeft:

“1.We wonder whether we are going to die

2. We look around for evidence and we observe in experience that each individual human being that we know of who has lived in the past has died. We know a few of thee deaths from direct experience, and we know most of them through authorities like obituary columns and history books. We also know that each individual living in the present believes himself to be mortal.

3.From this data base, we arrive by induction at the principle that “all men are mortal.” So far this is only probable, it’s probability increasing as the data base increases.

4.Then we come to understand that mortality is a property, and not just an accident(an attribute which may or may not belong to a subject), of man; that man is mortal by nature, since man by his nature has an animal body, which is organic, interdependent system of material organs all of which are needed in order for it to live, and any one of which can be destroyed simply by separating some of its material parts from other by a rock or a knife or a fire.

5.Having understood that “all men are mortal” by necessity, our deduction that “all men are mortal, and I am a man, therefore I am mortal,” can give us a conclusion we can be certain is true, for it not only validly follows from its true premises but validly follows from its certainly true premises” (213 Socratic Logic).

In these 5 steps, step 3 is inductive reasoning and step 5 is deductive reasoning.

Now let’s take a look at the cabin boy case. It’s assumed that everyone knows about the Regina v Dudley and Stephens, but here it is in short: in a case of survival cannibalism, three older crewmembers killed the weaker cabin boy in order to live by eating him. Let’s apply these 5 steps to practice combining inductive and deductive reasoning.

1.Is it just to kill one to save many even if it means killing an innocent cabin boy?

2. Now on to the sense observations. What are examples of justice? Providing aid to impoverished people in Haiti; a community working together to stop crime; a 5 year old with cancer receiving free health care; a university helping students gain and understand knowledge; a hospital curing the sick; the poor and unemployed finding work.

3. “We then make an inductive generalization on the basis of these examples (and this is inductive reasoning): it seems that justice is in the interest of the weaker rather than the stronger” (Socratic Logic 212).

4.”The fourth step is understanding the necessity of this universal which we have arrived at, by understanding the reason for it: justice is always in the interest of the weaker because of what justice essentially is, by its own nature. In step 3 we know the fact; in step 4 we understand the reason for it” (Socratic Logic 212).

5.We can then proceed to the application of the universal to the particular by deduction. Deductive reasoning: Justice is in the interest of the weak over the strong. The cabin boy is the weakest of the group. Therefore, it would be unjust to kill the cabin boy.

Right, in the next lesson the 3 types of induction will be covered: enumerative induction, analogical induction, and inference to the best explanation.

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