Tackle the ball, not the player
These reactions, if true, seem like strong criticisms but they are actually all examples of the same fallacy. Ad hominem arguments attempt to refute a claim by criticising the person who makes it rather than addressing the claim itself. In other words, these examples all tackle the player rather than the ball.
Imagine we discover that Einstein’s work was motivated by a desire for everlasting fame rather than a love of knowledge. What would follow about the truth of his theory of relativity? Absolutely nothing. Surely we wouldn’t think that this discovery gave us reason to reject the theory of relativity.
Imagine we discovered something similar about Nelson Mandela’s struggle against apartheid. This would in no way affect the truth of his belief that the apartheid regime was an evil one that he was justified to resist.
We might revise our assessments of Einstein and Mandela as virtuous men, but these discoveries would not affect the truth of what they said.
Exactly the same point can be made against all ad hominem arguments. The question of whether taxes should be cut is independent of the motivation of whoever proposes such cuts. What the US’s motivations were has no bearing on the truth or otherwise of its claim that the war against Iraq was justified. Perhaps scientists are merely trying to get research money, but it could still be the case that their research could have therapeutic benefits.
If ad hominem arguments are mistaken, why are they so common? The answer, I suggest, is that they are so easy. Take the tax cuts issue. Whether taxes should be cut is a complex question that requires weighing up many factors. These include not only questions of fact but also what principles to apply to these facts. The factual questions include: How would tax cuts affect government spending? Would cuts be made in health and education or only to ridiculous tertiary courses? The questions of principles include: Do income earners have a right to what they earn? Would tax cuts benefit the worst off in society or mainly the better off? Instead of cutting taxes, could there be a better use for the money? Since it is such a burden to have to consider all these questions before coming to a view on tax cuts, it is tempting to avoid them by focusing instead on the motives of the National party.
Why bother trying to assess the justifications for war against Iraq, its benefits and costs, when we could just say ‘but the US is only after oil’?
And what about cloning? Many people recoil at the thought of having to assess that complicated issue. Far quicker to wait for scientists to propose it and then vilify their motivations.
But assessing social and political issues is not that easy. To decide whether taxes should be cut, whether war is justified, and whether cloning should be allowed, we have to assess the merits of the issues themselves rather than the motives of their proponents.
There is one worry remaining. I’ve suggested that ad hominems, though fallacies, are common because those who make them are lazy. This of course sounds like an ad hominem.