Tag Archives: logical fallacies

The poor advocate fallacy

The other day while I was on the train home, I was pondering a few logical fallacies, as one tends to do from time to time. They are fascinating things and serve as useful tool to sharpen up one’s thinking. I know that I have, from time to time, been guilty of committing some of them, though I doubt I am alone in that. In this pondering, I found myself thinking of the following situation:

  1. Person A is an advocate of proposition X. Person B is an opponent of proposition X. Or rather, they may be an advocate of proposition Y which is incompatible with proposition X.
  2. Let us suppose that one of these propositions is true. By their mutual incompatibility, the other is false. For the sake of argument, we may assume that proposition X is true and that Y is false.
  3. However, person A’s reasoning for believing proposition X is faulty. Precisely what the flaw is need not concern us. There may be a long chain of reasoning in which just one or two steps are in error. The chain of reasoning used by person A we will call P. So what we are saying is that P does not imply X. However, there may be another chain of reasoning which is correct, lets us call it Q, which does imply X.
  4. What happens then is that person B notices the error in P and highlights it. However, they then assert that because P does not imply X and that person A has used reasoning P (without knowledge or understanding of Q) that X is false.

This is what I would call the poor advocate fallacy. A has not advocated a false proposition, but the fact that they used poor reasoning to get there has, in the mind of B, undermined their argument. Thus B is guilty of trying to take a shortcut and instead of using a valid line of reasoning to assert the truth of Y (and thereby de facto falsifying X), they use the falsity of the reasoning P to incorrectly conclude the falsity of the proposition X.

In thinking this through, I tried to look it up but could not find the fallacy named as such. So this is an open question to you – is this fallacy known by another name?

Or, and I cannot discount this possibility, is my reasoning faulty? If so, though, does that have any bearing on the whether or not my assertion that there is such a thing as the poor advocate fallacy? Because if there is such a thing and my reasoning is faulty, might a detractor to this idea be guilty of the fallacy themselves?


Such are the musings that occupy my mind from time to time. The fact that this got published is partly due to inspiration from Revd Claire and her take on some much tougher philosophy than the simple logic I propose above.

“Many Scholars” and the argument from authority

Having reflected on some of the methodology that Marcus Borg outlines at the start of his book, ‘Jesus: Uncovering the life, teachings and relevance of a revolutionary’ I wanted to use another aspect of the book to explore something I’ve been meaning to write about for some time: the argument from authority.

I’m guessing most of you are familiar with the basic outline of the argument from authority, but if not you can read a good primer here. There is another manifestation of it which Rational Wiki omits, but which I see from time to time. It is the appeal to “many scholars” or “most scholars” when you wish to convince your readers that you are not a crackpot and have the support of the majority of well-educated men & women.

In reading through Borg’s book, he employs it multiple times when he wishes to push forward an unorthodox idea. An example of this would be his advocacy of the Q hypothesis in the authorship of the synoptic gospels. One of the most insidious things about this argument is that the terms ‘many’ and ‘most’ are used interchangeably. At times, Borg does acknowledge the existence of an alternative point of view, but not always. I wouldn’t mind so much if he actually gave some references, but in citing these many scholars, he fails to name any. Given the nature of the views he espouses, I would suspect that he has in mind his fellow members of the now-defunct Jesus Seminar (pun intented) but one can’t be certain, given the lack of citation.

It brings to mind the motto of the Royal Institution, “Nullus in verba” roughly meaning “nothing on the word of another” or “take nobody’s word for it.” If we were to apply the same of critical thinking that Borg endorses us to, then we must be sceptical about his claim to have the support of many other experts in the field. If they are so numerous, why not name them? In some places in the book, he does provide references, making the inconsistency all the more suspicious. 

Further thoughts

All this does bring to mind some other thoughts I had a while back concerning the argument from authority, its limitations and misuses. In its purest form, it is a logical fallacy, though I would encourage you to look out for times when it may be misapplied.

Whenever I watch the news, I usually notice how ‘expert opinions’ are valued. If there’s a story about the economy, why not have someone who’s job title is “chief economist” take part in an interview? If there’s been a dramatic incident, who better to talk to than an eyewitness? There is good sense in opting for the best informed view, as one might reasonably expect their view to be more reliable than those of the average man or woman plucked off the street. Here, the argument from authority can get a bit blurry. Are we meant to take their word as authoritative or merely informative?

At the same time, applying nullus in verba in all walks of life is not a practical option. It’s an argument I sometimes have with those who take a Dawkinsian view of faith and claim that they don’t use it, though it’s an argument I have grown weary of having over and over again. Let me give an example to illustrate.

One of the first things I do in the mornings is check to see if my train is on time. If I read that there are cancellations or delays I act on trust that the information is more or less correct. I may skip breakfast or otherwise not take as much time as I normally do in getting out of the front door. What I don’t have is the luxury of doing is conductive any great enquiry as to whether the trains are delayed or by how much. I just act on the best information I have. That’s what it means to act on faith. You don’t necessarily settle for not knowing, but you do act on what evidence you do have, even if it’s not complete or conclusive.