The given statement of opinion, that appeared in newspaper call-in column portrays complete breakdown of logic. It is strewn with fallacious arguments, some of which cannot stand the test of deductive reasoning at all. To be able to identify such fallacies, it is imperative that we have a clear picture of what deductive reasoning entails as well as what fallacious arguments or statements really are (Vincent 2005).
Zearfsky and David (2002) say that deductive reasoning is the type of reasoning that subjects deductive arguments to an evaluation process in order to draw conclusions. Sets of hypotheses are evaluated to give rise to conclusions, the hypotheses themselves forming the premises for such conclusions. Below is an example of a conclusion made from deductive reasoning;
1. All animals are mortal.
2. A dog is an animal.
3. Therefore a dog is mortal.
The conclusion is that since a dog is a member of the set of things classified as animals and that all such things are mortal, a dog must be mortal.
Deductive reasoning can employ the law of syllogism (Zearfsky & David, 2002). This involves using two conditional statements from which a conclusion is drawn by combining the hypothesis of one of the questions with the conclusion of another. Below is an example of the application of syllogism in deductive reasoning. Consider the following statements;
1. If Martin is late for class, then he will be punished.
2. If Martin is punished, then he will miss the mathematics question.
3. If Martin is late for class, then he will miss the mathematics class.
The first statement forms the premise for the argument while the second forms the conclusion.
Deductive arguments are classified as either valid or sound.
Vincent (2005) says that an argument may be valid even if its premises are not true and its conclusion is wrong. All that matters is the relationship between the premises and the conclusion, that is, the conclusion must draw from the premises. Sound arguments are based on true premises. In sound arguments, both the premise and the conclusion must be true. It should be noted that the conclusion must be true if the premises are true in all deductive arguments.
A closer look at the article reveals statements based on invalid and unsound arguments. At the beginning of the excerpt the writer makes two unconditional statements in an attempt to employ syllogism in making his arguments; 1. That the homeless wear old worn out hippie gear, 2.that the people the witnessed identified as having killed the boy wore old worn out hippie gear and 3.That the boy was therefore killed by the homeless. While the argument advanced by the writer here is valid, it stands out as out rightly unsound because it is premised on a fallacy. It is not true that all homeless people wear such clothes. Neither is it a true fact that all who wear worn out hippie gear are homeless.
He later states that shelter should be provided for the homeless because they have nothing to loose by robbing, mugging etc. The statement is a farce as far as good arguments are concerned. This is because the conclusion does not draw from the premise. It can therefore be said to have the wrong conclusion. It should be noted that conclusions should always be made from the premises.
The writer also points out that ‘The witness saw people who were homeless…because the homeless all wear old worn out hippie gear’. This statement is fallacious because it deviates from the known fact that not all the homeless wear worn out clothes as suggested by the writer.
Furthermore, the writer states that the homeless lower property value and that they are jobless because they have chosen not to find work. These are fallacious assertions since it is known fact that the homeless are desperately in need of jobs and that they are not responsible for the low commodity prices.
In constructing arguments, due care should be taken to avoid such poor and fallacious reasoning as they tend to weaken arguments.
Vincent F. H., (2005). Thought 2 Talk: A Crash Course in Reflection and Expression, New York: Automatic Press / VIP
Zarefsky, David, (2002). Argumentation: The Study of Effective Reasoning Parts I and II, Oxford: OUP