The following is an example of the said argument taken from the website, www.fallacyfiles.com:
[Joe McCarthy] announced that he had penetrated “Truman’s iron curtain of secrecy” and that he proposed forthwith to present 81 cases… Cases of exactly what? “I am only giving the Senate,” he said, “cases in which it is clear there is a definite Communist connection…persons whom I consider to be Communists in the State Department.” … Of Case 40, he said, “I do not have much information on this except the general statement of the agency…that there is nothing in the files to disprove his Communist connections.”
The fallacy exists in the assumption that the burden of the evidence is to prove that Truman’s communist connections are not true when it was never established to be true in the first place. This type of error of logic is committed when the lack of evidence is used to prove something and this is false because the lack of evidence is not evidence in itself. One’s ignorance or lack of knowledge cannot be used to prove or disprove something.
2. Begging the question
This fallacy, also known as “circular reasoning”, occurs when a premise is used as the conclusion or when a claim that is yet to be established or proven occurs as the conclusion. The fallacy is illustrated in following example taken from the book, The Abortion Controversy by Helen Alvare:
To cast abortion as a solely private moral question,…is to lose touch with common sense: How human beings treat one another is practically the definition of a public moral matter. Of course, there are many private aspects of human relations, but the question whether one human being should be allowed fatally to harm another is not one of them. Abortion is an inescapably public matter.
This writer sees more than one point of flawed reasoning in the given example. Firstly, there is the assumption that the idea of morality is dependent on whether the issue at hand should be considered a public or private matter. Second, there has been no attempt to expound what qualifies as “the private aspects of human relations” and it necessarily contradicts the given definition of a public moral matter which is “how human beings treat one another.” To say that something is practically the definition of something else does not prove that it is. Thirdly, the implication that equates abortion to allowing “humans to fatally harm another” is but another assumption and does not prove the conclusion, because that premise itself is in need of proof.
3. Common belief
This fallacy occurs when people hinge the truth of a claim or proposition on what is believed by many or popular belief. Popular belief is simply statistics. The prevalence of an opinion does not account for the truth of a claim.
For example just because many people believe there is a God or just because certain cultures believe that illnesses are caused by bad spirits does not make both claims true. The truth of a claim cannot be proven by sheer popularity.
This error in logic occurs when the characteristics of the parts are assumed to be true for the whole. Take for example the following statements from the website www.fallacyfiles.com:
1. The universe has existed for fifteen billion years.
The universe is made out of molecules.
Therefore, each of the molecules in the universe has existed for fifteen billion years.
While it may be true that certain characteristics can apply to both the parts and the whole, this is not an absolute truth. In the example given, although it is possible that age (i.e. fifteen billion years) may be a shared characteristic, it is not the case for the example given because although the universe has been in fact been in existence for fifteen billion years, not all of its molecules has been existing since then.
List of references:
Engel M. With Good Reason: An Introduction to Informal Fallacies (Fifth Edition). St. Martin’s, 1994
Krabbe, E. Appeal to Ignorance”, in Fallacies: Classical and Contemporary Reading. USA: Penn State Press, 1995
Rovere R. Introduction to Logic (Fourth Edition). USA: 1960.
Walton, D. The Essential Ingredients of the Fallacy of Begging the Question, Fallacies: Classical and Contemporary Readings. USA: Penn State Press, 1995.