Appealing to authority and Ad Hominems

Appeal to Authority

Sometimes we need to make decisions on what is the correct view to hold, even if we cannot know it through a sound argument. Imagine seeing an extremely difficult mathematical problem, one that only professional mathematicians have the ability to solve. We cannot use our reasoning skills to know the answer if we are not a professional mathematician. If we really want to know the answer, we could apply at university to become a mathematician, and a few years later come to know the answer, or we could ask a mathematician to tell us the answer. When we ask the mathematician to tell us the answer, what we are doing is appealing to an authority.

In principle, it is generally better to try to come to answers to things without appealing to authority, but due to the time and resources it would take to do so, this is extremely untenable. To avoid appealing to any authorities in our daily lives, we would have to have the same level of knowledge as a doctor, mechanic, plumber, builder, and so on. We simply do not have the time to be all of those things. So, we will need to appeal to an authority (some may call this an appeal to an expert). This is one way we could appeal to an authority in an argument:

  • 1. My doctor says I need surgery
  • 2. My doctor is right about this
  • Therefore,
  • 3. I need surgery

The argument is valid, and it could be sound, but it begs the question. It begs the question because I cannot accept the premise that my doctor is right about this without already accepting the conclusion.

This is how we could make the argument sound without begging the question:

  • 1. My doctor says I need surgery
  • 2. My doctor is an expert in these matters
  • 3. Experts are usually correct in their area of speciality
  • Therefore,
  • 3. I probably need surgery

As mentioned in the previous tutorial, weakening the conclusion can make the argument sound. However, appealing to authority will always require a weakened conclusion, because even experts are fallible, it will always be possible that the expert is incorrect. That said, the probability of an expert’s opinion being correct on the subject will always be greater than the opinion of the layperson. It is possible that the layperson can be right and the expert be wrong, but it is not probable.

This of course raises the question of who counts and who does not count as an authority? Walter Sinnott-Armstrong and Robert Fogelin (2010, p 363-4) have offered a useful set of criteria to answer this question:

  1. “Is the cited authority in fact an authority in the appropriate area?
  2. Is this the kind of question that can now be settled by expert consensus?
  3. Has the authority been cited correctly?
  4. Can the cited authority be trusted to tell the truth?
  5. Why is an appeal to authority being made at all?”

Let’s try to apply this to our doctor example. Number (1), if the doctor was just a general practitioner (GP), it would be wise to get an opinion from a specialist, since even though they are both experts, the specialist would be an authority in the appropriate area. Number (2), if time is not of the essence, getting a second opinion from another specialist would strengthen the probablity that you do need surgery. (3), If the doctor/specialist has explicity said that you need the surgery, they have been cited correctly. (4) There seems to be no reason to believe they would lie about something like this. (5) If I am not a specialist, I do not have the means to know whether I need surgery without getting this advice.

The more criteria 1-5 can be satisfied, the more probable it is that the advice is correct. It will always be possible that it is incorrect, but it is far more probable that the advice is correct.

Ad Hominems

Appealing to an authority is when we appeal to a person making a claim, and that based on who that person is we treat what they are saying as probably right. However, there are times when we will appeal to a person making a claim, and based on who that person is we treat what they are saying as probably wrong. This kind of argument is called Ad Hominem, which is latin for ‘to the man’. Here is an example of an Ad Hominem:

  • 1. My doctor says I need surgery
  • 2. My doctor is very rude
  • Therefore,
  • 3. I do not need surgery

This argument is clearly invalid, the premise that the doctor is rude has nothing to do with them being right or wrong about needing surgery. This kind of Ad Hominem is when we are appealing to the person’s character. And this is always invalid. Even if we weaken the conclusion to “I do not need to listen to them about this” is invalid, because it does nothing to strengthen or weaken the probability of what they are saying is true or false. Here’s a more common form of Ad Hominem:

  • 1. My doctor says smoking is bad for your health
  • 2. My doctor smokes
  • Therefore,
  • 3. Smoking is not bad for your health

In this case, this is appealing the person being hypocritical. Sometimes appealing to hypocracy is legitimate regarding telling someone to behave like they ought to behave, but similar to appealing to a person’s character, it does nothing to strengthen or weaken the probability of what they are saying.

Let’s take a look at one more kind of Ad Hominem:

  • 1. My doctor says I should use the vitamins
  • 2. My doctor is a shareholder of that vitamin company
  • Therefore,
  • 3. I should not use these vitamins

This is invalid, however, this one can have its place when and only when it is being used whilst testing an authority. Going back to number (4) “can the authority be trusted to tell the truth”. If this criteron cannot be satisfied, and in the case of being a shareholder of that vitamin company, it cannot due to a conflict of interest, then he should not be the authority being used. It would be better to get another opinion from another expert that does not have that conflict of interest. So, the conclusion here should be: I cannot use my doctor as an authority. This is because we’re still not entitled to say that I should not use those vitamins. However, this only applies to appeals to authority, if someone gives an argument that you have the ability to analyse, then appealing to conflict of interest is irrelevant.

Test questions

Try to see whether these arguments are appeals to authority or Ad Hominems, and try to see if they are sound:

  1. My friend says that most vegetables are more healthy than most meats, so we should eat more vegetables than meat, but I saw him eating KFC the other day. So, I shouldn’t listen to what he says.
  2. 97% of climate scientists say that climate change is man made. Climate scientists are experts on these matters. So, Climate change is most probably man made.

If you wish to ask any questions, seek clarification, raise some objections, or check how you went on the test questions, please write them in the comments section and I will try respond as soon as I can.

I highly recommend purchasing the book ‘Understanding arguments’ by Walter Sinnott-Armstrong and Robert Fogelin, which is available for purchase in the link below. If you do purchase the book via this link, you are helping support this webpage. Thank you.

Published by

Andrew Tulloch

I have a Bachelor of Arts majoring in Philosophy and Sociology, with a Political Science minor. I also have an honours degree in Philosophy. I am currently studying for my PhD in Philosophy.

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