Let me start by simplifying some stuff. An argument, in philosophy, is not the same thing as a quarrel. The objective of an argument is not to knock your opponent down or to impress your readers or listeners. The purpose of an argument is to furnish good reasons in support of your conclusion; reasons that all parties to the dispute can affirm, whether they like it or not. Also, an argument is not just a mere denial of what the other person says. Even if what your challenger says is false and you know it to be false, to resolve your dispute you have to present arguments. And you haven’t yet provided an argument against your disputant until you submit some reasons that show him or her to be mistaken.
The way a person state their claims either in writing or speech shows if they are critical thinkers or just emotional blubbers. When we think critically, we don’t perpetually question everything (at least not in the strict sense of that phrase). Rather, we are actively concerned with the reasons and explanation one can have for making a particular claim.
When someone, for example, claims that God exists, we can critically appraise this claim. We may ask, “What are some of the reasons that sustain a belief in God’s existence?” rather than simply accepting that claim since it would be arduous to figure out whether it’s true. Hence critical thinking demands that we apply sound reasoning and at the same time notice when others are not reasoning soundly.
But how do we know when we’re reasoning well?
Well, there is a field of study called “logic” committed to finding a pretty and meticulous answer to that question. Logic is the formalisation of arguments, which attempts to ascertain which arguments have a solid sort of form.
Ad hominem fallacy
Now let me give an instance of how the most regularly used logical fallacy (an error in reasoning) is committed. It is called an argumentum ad hominem. Pull any newspaper and go to any article, and I can guarantee you that as sure as the sun follows the day you will strike upon not less than two ad hominem. You are also likely to bump into other logical fallacies such as hasty generalization, appeal to authority, appeal to emotion, appeal to ignorance, the argument from personal incredulity etc.
Now, follow my three scenarios below.
A sceptic attacking John instead of his argument, and it goes like this,
1. John maintains that Jesus Christ was not just a true historical figure but also a Savior; he claims that the New Testament documents are the best-attested documents of antiquity and that they were composed within the first sixty years after the death of Christ. But John is neither a historian nor a Scripture scholar, so what business does he have? Talking as an expert on these matters is beyond my ken?
2. In a moment, John will offer arguments for why we should believe that Jesus Christ was not just a real historical figure but also a Savior. Keep in mind, John is an adult male person, of sane mind, who thinks that an invisible God listens to his prayers and lives in his heart. Can we trust what he has to say on anything of importance?
3. John wants us to believe that Jesus Christ was a real historical figure and a Savior. He states that I hardly understand the New Testament and the Christian religion. Yet when I challenged him a minute ago to name one of the four Gospels that portrays people resurrecting and appearing to people in Jerusalem, he looked clueless!
You will notice that in all three examples the arguer did not tackle John’s argument but instead charged after him as a person. In the first example, we are led to believe that John’s argument is unreliable because he is not a historian or a Scripture scholar. Now, there is nothing wrong with needing evidence or expertise before admitting something as true, but John’s opponent doesn’t do that; instead, he dismisses John based on his lack of formal training. But John’s lack of formal training has no bearing on whether his argument was sound. Possibly John is also short and has bad breath. None of that is evidence that his argument is unsound.
Poisoning the Well
Momentarily, take a look at the second example. Here we observe a variation of the ad hominem fallacy normally called “poisoning the well.” This fallacy is a preemptive assault on the character of a person before they have had the chance to make an argument. Over, this fallacy rests not in questioning the authenticity of John but in making him seem deluded and a jerk before he has an opportunity to make his argument.
The third example is also a sort of ad hominem argument, called tu quoque. The tu quoque fallacy consists of blaming your disputant of the same thing he has accused you of. “Well perhaps I am a thief, but so are you!” Well, possibly he is, but that fact in and of itself does not endeavour to address —much less refute—his argument.
If you find yourself on the receiving end of the ad hominem fallacy, I would recommend that you calmly point out to the one you’re dialoguing with that attacking you (your character, intelligence, etc.) has nothing to do with the argument beforehand. Finally, invite him or her to use his energy on that instead.
Richard Whately, one of the most prominent of the 19th-century researchers into informal logic, sagely said, “A very long discussion is one of the most effective veils of Fallacy; …a Fallacy, which when stated barely…would not deceive a child, may deceive half the world if diluted in a quarto volume.”