<P> Circumstantial ad hominem points out that someone is in circumstances such that they are disposed to take a particular position . It constitutes an attack on the bias of a source . This is fallacious because a disposition to make a certain argument does not make the argument false; this overlaps with the genetic fallacy (an argument that a claim is incorrect due to its source). </P> <P> The circumstantial fallacy does not apply where the source is taking a position by using a logical argument based solely on premises that are generally accepted . Where the source seeks to convince an audience of the truth of a premise by a claim of authority or by personal observation, observation of their circumstances may reduce the evidentiary weight of the claims, sometimes to zero . </P> <Ol> <Li> Mandy Rice - Davies's famous testimony during the Profumo Affair, "He would (say that), wouldn't he?", is an example of a valid circumstantial argument . Her point was that a man in a prominent position, accused of an affair with a callgirl, would deny the claim whether it was true or false . His denial, in itself, provides little evidence against the claim of an affair . <Dl> <Dd> However, this argument is valid only insofar as it devalues the denial; it does not strengthen the original claim . To construe invalid evidence of the denial as valid evidence of the original claim is fallacious (on several different bases, including that of argumentum ad hominem and appeal to emotions); however likely the man in question would be to deny an affair that did in fact happen, he is even more likely to deny an affair that never happened . (For example, inferring guilt from a denial--or, less starkly, excessive devaluation of a denial--is a very common feature in conspiracy theories, witch - hunts, show trials, struggle sessions, and other coercive circumstances in which the person targeted is presumed guilty .) </Dd> </Dl> </Li> <Li> Glassner suggests that Bennett is somehow unqualified to criticize rap music because of positions Bennett has taken on other issues . However wrong Bennett may have been on other issues, such as the funding of public television or illegitimacy, that does not mean that his criticisms of rap were mistaken . </Li> </Ol> <Li> Mandy Rice - Davies's famous testimony during the Profumo Affair, "He would (say that), wouldn't he?", is an example of a valid circumstantial argument . Her point was that a man in a prominent position, accused of an affair with a callgirl, would deny the claim whether it was true or false . His denial, in itself, provides little evidence against the claim of an affair . <Dl> <Dd> However, this argument is valid only insofar as it devalues the denial; it does not strengthen the original claim . To construe invalid evidence of the denial as valid evidence of the original claim is fallacious (on several different bases, including that of argumentum ad hominem and appeal to emotions); however likely the man in question would be to deny an affair that did in fact happen, he is even more likely to deny an affair that never happened . (For example, inferring guilt from a denial--or, less starkly, excessive devaluation of a denial--is a very common feature in conspiracy theories, witch - hunts, show trials, struggle sessions, and other coercive circumstances in which the person targeted is presumed guilty .) </Dd> </Dl> </Li>

The person or circumstance in opposition to the main character is the