1. On Arguments from Testimony
ECA 2017, Fribourg
MARTIN HINTON
UNIVERSITY OF ŁÓDŹ

2. The Issue
"No weakness of human nature is more universal and conspicuous than what we commonly call CREDULITY, or a too easy faith in the testimony of others“ David Hume (1740: I,III,IX) How can we tell a too easy faith apart from the trust necessary to live with and learn from one another?

3. Plan of the Talk There are three main themes to this paper:
Why discussion of arguments from testimony has come to be dominated by appeals to ‘Expert Opinion’.
Why this concentration and the neglect of other forms of testimony is a bad idea.
What would be a better idea – one generalised argumentation scheme covering all forms of argument from testimony, avoiding the problems concerned with the notion of ‘Expertise’, and placing the disputants themselves at the heart of the matter.

4. Why discussion of arguments from testimony has come to be dominated by appeals to ‘Expert Opinion’

5. From Dignity to Domains
John Locke’s famous Ad Verecundiam argument has been transformed from an always fallacious appeal to the dignity of certain personages to a defeasible presumptive argument, where the assertions of an ‘authority’ usually an ‘expert’ or ‘epistemic authority’ are appealed to in order to decide the truth of the matter.

6. A Comparison of Schemes
Locke’s Ad Verecundiam schematised
Walton’s Appeal to Expert Opinion
Source E is a respected authority. E asserts that proposition A is true (false). It is improper to dispute the claims of respected authorities. What it is improper to dispute should be accepted. Conclusion: It is improper to dispute A and it should be accepted as true (false).
Source E is an expert in subject domain S containing proposition A. E asserts that proposition A (in domain S) is true (false). If source E is an expert in subject domain S containing proposition A, and E asserts that proposition A (in domain S) is true (false), then A may plausibly be taken to be true (false). Conclusion: A may plausibly be taken to be true (false).

7. So what?
As Jean Goodwin, among others, has pointed out there’s more than one type of ‘authority: “the authority of command, the authority of expertise and the authority of dignity – the real ad verecundiam” (1998: 278). However, the appeal to expert opinion is more closely related to other appeals to testimony than to appeals to command or dignity. Often referred to as ‘epistemic authorities’, experts have taken over the field.

8. Why this concentration and the neglect of other forms of testimony is a bad idea.

9. The problem with experts
Walton’s argumentation scheme for Appeal to Expert Opinion contains just three premises but, in the expanded version, as many as twenty-one critical questions. Such as: “Can it be shown that the opinion given is one that is scientifically verifiable?” and “Is E honest?” (Walton, Reed & Macagno, 2008: 93). The scheme effectively says: what experts sincerely say to be true can be taken to be true. Leaving the all important question: who or what is an expert? And the critical questions make it clear that a layman has no way of knowing, and another ‘expert’ can only guess.

10. Further problems
Studies in Expertise and Experience, an academic field in itself, simply has no accepted definition of what an expert is. There is also the problem of relativity: an expert in one company or age may not be considered on in another. Should every appeal to ‘epistemic authority’ – even relatively simple questions - require the same standards? Walton, like others, also refers to ‘domains’ and ‘fields’. This troubles me, since it suggests that once a person is established as an expert in a particular domain, that person can be trusted to give good opinions on every aspect of that domain – perhaps even aspects which exceed the expertise of everyone in that field: such as predicting future developments. Conclusion: fulfilling the criteria of being an ‘expert’ is neither a necessary nor a sufficient condition for being a credible authority.

11. What would be a better idea

12. A unified argumentation scheme
Instead of Walton et al.’s (2008) three schemes – argument from position to know, argument from expert opinion and argument from witness testimony, I propose one:
Argument from Testimony
Witness W testifies that proposition P is true.
It is reasonable to believe that W is in a position to make valid claims about P (because of circumstance C).
Therefore: it is reasonable to believe that P is true (given C)

13. Support and CQs
I believe this move can be made since all three forms of argument rely on the same power of reasoning: that is, that, for whatever reason, there is a person more highly placed than any of the current disputants in what I shall call the Epistemic Hierarchy, concerning this particular question and that all parties therefore agree to accept that person’s testimony ahead of their own opinion.
The important Critical Questions would be:
Does C actually pertain?
Does C actually put W in a position to make such claims?

14. Why is it better?
There are both theoretical and practical reasons for favouring this approach.
By the principle of economy, it is better to have one scheme than three, if possible.
By the principle of clarity, it is better to avoid words, such as ‘expert’ and ‘domain’, which may themselves be the subject of further disagreements.
By separating circumstances in themselves from their relevance to the question at hand, we side-step the issue of ‘fields’ and have a mechanism to deal with easy or impossible questions.
By accepting that circumstance C could be any kind of knowledge or competence, we no longer need to agree on a definition of ‘expert’ which could be applied to witnesses.

15. In conclusion
Argumentation theory has gained nothing by separating arguments from testimony into three categories. Focus on appeals to experts has led down the blind alley of trying to define what an expert actually is. My unified scheme is economical, clear and better able to cope with the reality of decision making (and disagreement) on the basis of testimony. However, in fairness to Walton, much depends on what we see as the purpose of the argumentation scheme. If schemes are intended to describe types of arguments actually made, then clearly, appeals to experts are such a type. I believe that it is situation and circumstance alone that differentiate the types of testimony: for Walton, that may be enough.

16. References
Goodwin, J. (1998). Forms of authority and the real ad verecundiam. Argumentation 12: Hume, D. (1740)[1978]. A treatise on human nature. Oxford: OUP. Locke, J. (1690)[1975]. An essay concerning human understanding. Oxford: OUP Walton, D., Reed, C & Macagno, F. (2008). Argumentation schemes. Cambridge: CUP

17. Workshop on Informal Logic and Linguistics
An Invitation…
WILL Two
Workshop on Informal Logic and Linguistics
May 11th 2018
University of Łódź
Poland