In the argumentum ad hominem circumstantial, the appeal is to the special circumstances of the person with whom one is arguing. Instead of trying to prove the contention true or false on the evidence, its acceptance is urged because of the position and interests of those appealed to.
You can’t accept the legitimacy of lending for profit. You are a Christian, and Christ drove the money-lenders from the temple.
(This is not a general argument. It might not do much for a Hindu or a Jew, for example. The listener is invited to assent because of his Christian convictions.)
In a similar way people can be asked to accept a view because of their circumstances as members of the political party which supports it. In this version of the fallacy the error comes in by bringing the particular position of the audience into what is urged as a generally accepted truth. While such tactics might indeed convince that specific audience, they would not establish the Tightness or wrongness of what is urged, nor the truth or falsity of a statement.
No one in this university audience can be opposed to handing out state money to subsidize services, otherwise you would not be here, occupying a subsidized place.
(Actually, it is other state handouts which students oppose.)
A variant of the fallacy dismisses a person’s views as representing only their special circumstances. It assumes that an oil company executive can reflect only his corporation’s interest when he voices an opinion on the future of energy supplies. In the first place, the executive may well have independent views which differ from those of his company. In the second place, there is nothing to say that the corporation view is not the correct one, self-interested though it may be. The fallacy arises in this version by the wanton dismissal of possibly relevant material as much as by bringing in irrelevant matters such as the circumstances of the audience. Even if it can be shown why an opponent thinks as he does, it still does not show him to be wrong. (‘As an opera-lover, you will be the first to agree that we need more subsidy for the arts.’)
The appeal to special circumstances occurs in arguments addressed to specialist audiences. The American expression ‘building a constituency’ refers quite often to the process of adding together enough interest groups, all of which give support on account of their special circumstances. An adept, if unscrupulous, politician might build a power-base by directing argument not to the general good of society but to the special circumstances of public-sector employees, trade unions, welfare recipients, ethnic minorities and groups involved in sexual politics. The Tightness or wrongness of the programme need not come into it if enough special circumstances can be appealed to.
Both versions of the argumentum ad hominem circumstantial can be used to advantage. You should employ the first version with respect to circumstances which are broad enough to include fairly large audiences. (‘You, as members of the working class, will appreciate … ‘) Especially useful to you will be the nominal membership of the Christian Church. Many people like to think of themselves as Christians, although they do not like the obligations which serious Christianity would impose. Thus when you appeal to them that as Christians they can hardly oppose your views, they will be forced into a reluctant and resentful acquiescence you could never have gained otherwise.
The second version is spectacular in the rejection of expert evidence against you. An expert is someone in the field, and as such his views represent only his circumstances as one who is involved. Thus, when the town-planner refutes your claims on town-planning; when the oil company expert shows what nonsense you have uttered on energy; and when the businessman exposes your cockeyed views about business, you smile sweetly in each case and observe: ‘Well he would say that, wouldn’t he?’