Tag Archives: logic

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.

What kind of evidence would you like?

There were two instances recently where the idea of evidence and epistemology came to the fore. I just wanted to explore my own thoughts on the matter and to find out what you think. The first came in an internet discussion which was raking over old ground of christianity v atheism. Someone had made the statement that extraordinary claims require extraordinary evidence and I couldn’t resist the bait to jump in and correct their use of this logical fallacy.

The second was when I was at the Job Centre Plus and I was asked to provide “proof” of my savings. Those that know me will be aware that I am quite pedantic, especially when it comes to the semantic difference between proof and evidence. What they were really after was strong evidence since proof is so much more an exacting standard that is almost impossible to achieve outside of the platonic world of mathematics.

Without going into too much detail of each specific case, this got me thinking about what kind of evidence one accepts and how we compare that to what is available. In the case of christianity, the extraordinary claim at the heart of my belief is the resurrection of Jesus. Yet I am constantly told that this requires extraordinary evidence.  So, I ask, what kind of evidence would you accept? The event was a one-off and so the scientific paradigm (as much as I am in favour of it) doesn’t apply since you cannot repeat any experimentation under controlled conditions. Instead, we have to adopt the mindset of the historian, where we have to deal with the evidence as it stands. We cannot create evidence; all we can do is uncover that which already exists.

In the case of the jobseekers’ allowance (JSA), most of my savings are held in e-savings accounts. The reasons for this are compound, but one of these is that they use less paper since I don’t get statements through the post. I just log on to my online bank to see what the balances are. I offered to log on and demonstrate to the staff at the job centre how much I had in each account (I’m still not certain about the precise reason, but I won’t get JSA if they don’t know how much I have in my accounts) but they wouldn’t accept the evidence that existed and which I was willing to show them.

The interesting thing is that evidence only ever points to truths which already exist. The evidence only affects (or effects, even) our knowledge of those truths, it doesn’t create truth out of the void. In other words, the ontology is independent of the epistemology. While we would all surely love to have all the evidence we want to support or falsify our views in the exact format we would like, the universe isn’t really that simple.

There are instances where evidence is destroyed or lost which may lead us to areas of great uncertainty but which do not impinge on the truth (or otherwise) of whatever matter we are investigating. For example, we know very little about the contents of the ancient library of Alexandria, or the precise location of where Julius Caesar crossed the Rubicon. Sometimes all the evidence we have is that of the eyewitnesses to an event.

It is often easier to dismiss an idea on the basis of it lacking the kind of evidence you would prefer than it is to undertake a serious examination of the evidence that exists. There is much said and written about the historicity of the christian claims, though of those I have read lately, the best are those by Tom Wright: Surprised by Hope (shorter and written at a very accessible level) and The Resurrection of the Son of God (longer and more detailed). To give a snippet, he states in the former “I do not claim…that I have ‘proved’ the resurrection I terms of some neutral standpoint. I am offering, rather a historical challenge to other explanations, and to the worldviews within which they gain their meaning….No other explanations have been offered, in two thousand years of sneering scepticism against the Christian witness, that can satisfactorily account for how the tomb came to be empty, how the disciples came to see Jesus, and how their lives and worldviews were transformed.”

When we lack definitive proof, as we do in 99% of all things, all we have to rely on is incomplete evidence. It is up to us individually to decide how we treat that evidence and what conclusions we may draw from it. My opinion is that we should maintain a healthy scepticism (here, my idea of scepticism differs a little from Wright) and that we should always consider the possibility that we might be wrong, no matter how much we might want something to be true (or untrue). This scepticism leads to an inevitable doubt about that which we hold dear to our hearts. But so long as that doubt leads to investigation and hopefully to increased knowledge, doubt is not a bad thing. If it leads to disbelief where we preclude possibilities then we are wilfully choosing to neglect our intellects; this, I do not agree with.

So those are my thoughts. What are yours?