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Writer's pictureNic N. Sharp

How to Dismiss a Sceptic: When is an Epistemic Challenge a Legitimate One?


Introduction:


Scepticism is really annoying. It casts doubt over everything, and takes nothing for granted. More academically put: despite the sceptic’s integral role in eliciting stronger justificatory grounds for our beliefs, their epistemic demands are insatiable. So, how do we essentially tell the sceptic to shut up in a philosophically sophisticated way? I think Vavova (2014, 2015, 2021) has shown us the way. She has articulated perfectly reasonable grounds to determine when, and why, an epistemic challenge is illegitimate and can be hand-waved, and when it is legitimate and is deserving of serious rational belief revision. The sceptic’s epistemic challenge falls within the former camp, and in this brief piece, I think it’s worth recounting.


Despite the fact that sincere scepticism is – thankfully – rare and much out of the philosophical vouge, it does present itself in more complex debates. For instance, the initial context in which Vavova produces this response is against moral scepticism, within the broader evolutionary debunking argument debate. [1] But I’ll put that dialectic aside – see footnote 1 if you are curious as to how that very briefly works – and take on what I consider to be wholesale scepticism. That is, a generic scepticism that can be applied to cast doubt over just about any domain of knowledge claims. In what follows, I cut straight to the chase with Vavova’s Optometrist vs The Sceptic example, delineate how it characterises the sceptics epistemic challenges, and in doing so, makes a case against said sceptical challenges, before going on to drawing out what I take to be the epistemic principle at play along with my own comments.



Section 1: Vavova’s Response & The Criteria of A Legitimate Epistemic Challenge


Vavova’s (2015: 2-4) Optometrist vs The Sceptic, as I’m calling it, goes as follows:


Suppose an optometrist conducts a test on your visual-system, with results that suggests with reasonably high probability that you are colour blind. That is, the optometrist has given you evidence of the (likely) probability that a set of your beliefs (regarding colour) are erroneous.


Now suppose a sceptic, who similarity wishes to convince that your colour beliefs erroneous. This sceptic – not being so committed to the Optometrists’ process of accruing of evidence, given the extent of their scepticism – asserts that you should be doubtful of your colour vision beliefs truth-status because it is a possibility that they are in error.


Consider the following differences, and it becomes all the more obvious where Vavova’s sceptic-refuting move takes off. In the latter scenario of the sceptic, your colour beliefs have been challenged but only on the basis of the mere possibility of error; it is possible that they are wrong, and therefore you ought not to trust your colour-beliefs. The former optometrist case however, has evidence which suggests that your visual system is in all likelihood, probably an erroneous one. Now the sceptic might not think evidence of any kind is really any good, but this really goes against their favour. Their expressed doubt is substantiated by nothing other than pure conjecture; whereas the optometrist has substantiation via evidence (assuming this evidence is highly replicable and reproducible, and thus can be attributed with the kind of reliability we expect of any kind of respectable form of evidence that might carry epistemic weight). [2]


It is for this difference, Vavova tells us, that we are under no obligation to take the sceptics doubts seriously. They do not pose what qualifies as a legitimate epistemic threat – that is, an epistemic challenge that we ought to take seriously enough to rise to giving a proper defence – wherein the challenge they posed is without substantiation. In fact, sceptical challenges are so illegitimate in that they are also wildly untargeted doubts, where as much could be said against any, or all, beliefs – that is, there is no belief for which this could not be said for, as the conceivable possibility of error may always linger. The difference can thus be stated: while the sceptic raises the possibility of error, their epistemic challenge goes unsubstantiated; and where the optometrist raises evidence that is indicative of the probability of error, their challenge is substantiated. And that is the difference that makes the optometrists’ epistemic challenge of your colour-beliefs legitimate, and the sceptics illegitimate. The criteria of a legitimate epistemic challenge can thus be accordingly termed: the criteria of a legitimate epistemic challenge, or the criteria of evidence of error.



Section 2: The Epistemic Principles of Vavova’s Criteria


Now let’s reflect on what this all really means for not only dealing with sceptics, but in applying this lesson to our epistemology more broadly. I believe the criterion I have drawn from Vavova is suggestive the following, highly plausible, epistemic principles:



A)   The Evidence of Error Legitimising Principle:

An epistemic challenge of a targeted (set of) belief(s) is legitimately vulnerable to sceptical doubts – and therefore ought to be taken seriously enough to warrant a response, otherwise submit to defeat – only if: that doubt is substantiated by (demonstrable, reliable, and probable) evidence of error. [3]

 

B)   The Rational Belief-Revision Principle:

If A) is the case, such that there is evidence of a targeted (set of) belief(s) error – i.e. likelihood of said belief(s) falsity, or non-truth convergence – then an agent cannot rationally maintain confidence in those beliefs.



With these principles drawn out, I’ll now expand and clarify the above principles with some further explanation. Principle A) draws the wind from the Sceptics sails before they can even set course. No evidence of error? Great! No challenge to engage with. This is essentially a good safeguard to stop things getting overwhelmingly demanding and stop us from wasting our time from a bad conversationalist. Principle B) tells us what we – hopefully – already know. To play on Hume’s adage: we proportion our beliefs to the available evidence of our errors.


Section 3: Lingering Thoughts & Closing Remarks


But now I want to linger a little longer on why we might we doubt the plausibility of Principle A)? I think we might if we get confused by the meaning and scope of an age-old move, that also goes by the phrasing of a placing the burden of proof? The burden-of-proof move places said burden for evidence on asserters of knowledge claims, such as, say, the claim that: There is a Tea cup and saucer currently passing our very orbit (to go by B. Russell’s classic example in demonstrating scepticism against theological claims posing as knowledge).


If one thinks this is essentially what this principle boils down to, I want to take some time to make the case for its difference. Principle A) is different, and importantly, does not leave us with any funny sounding implications! How so? Principle A) does, in a sense, place a burden of proof, but on a wholly different audience. As stated, the traditional usage of the burden-of-proof move places the request for evidence when a knowledge claim is being asserted. What Principle A) does however, is that it places a burden for evidence on defeaters of knowledge claims (i.e. those who seek to undermine the grounds, or claim itself, to some kind of knowledge). Now there is a moment here in which funny implications might follow that sound implausible. It does seem silly, you might think as I briefly did, that one can go ahead and make absurd assertations that are irrefutable until defeated by evidence of error. No! That’s not what is going on here. If it were, then the sceptic’s epistemic challenges would be legitimate until defeated. But the absurd asserter of such claims is doing just that: making knowledge claims!


Principle A) does not imply, or reduce to, any funny business via the burden-of-proof because it only contends with identifying legitimising grounds for epistemic challenges, proposed by defeaters of knowledge claims. It has nothing to say of asserters of absurd knowledge claims. Which is why it is wholly distinct from, and compatible with, the burden-of-proof move in its own right. Which we may formulate as follows:


C)   The Burden-of-Proof Principle:

A knowledge-claim is epistemically sound (and therefore legitimate as in worth taking seriously) only if: it is substantiated by (demonstrable, reliable and highly likely) evidence of certainty.


So now what? I have merely clarified that: sceptical defeaters need evidence to legitimately defeat, and asserters need evidence to legitimately assert. Sounds good. The best bits in the end are really just that Vavova’s criteria lends to principle A), importantly requires B), and is distinct from and compatible with C). These all appeal to our most plausible epistemic sensibilities, and give us a good, sophisticated sounding voice to tell a sceptic to piss off. Happy days.


But wait… Isn’t the sceptic going to doubt evidence produced by asserts of defeating evidence of error (i.e. A) and asserters of knowledge-claims? Sure, they will expectantly do so! But, as Principle A) holds, their doubt only poses a legitimate epistemic threat where they have evidence of that evidence-of-error’s erroneousness. And that forces them into Principle A) itself, rendering them no longer sceptics but philosophico-scientific agents. The Optometrist ticks all the boxes: they A) produce evidence of error to defeat knowledge-claims; which presupposes that they have C) evidence of certainty in their knowledge-claims of having obtained evidence-of-error – what we might call higher-order evidence, which is just what it is to justify one’s evidence as evidence-of-error. Now of course question remain regarding of chains of justification here; what after all, justifies that higher-order evidence? And there is also the related question of what qualifies evidence as sufficiently justificatory; and what a criterion of its qualification – under terms such as ‘reliable’, ‘demonstrable’, and ‘likely enough’ – really means at another level of analysis. These are the annoyingly important questions of epistemology, which most ironically arise thanks to the credit of a sceptic and a compulsive urge to shew them off.

 

 

Footnotes:


[1] This can be roughly be summarised as an argument that draws out the implications of evolutionary theory in accounting for the vast majority (in practice), if not all (in principle), moral psychological practices and dispositions, to then go on to conclude that any kind of objective (i.e. attitude independent) moral knowledge is wholly improbably, if not impossible. Hence, objective moral knowledge – supposing, rather generously, that there was such a thing on behalf of the arguments target audience – is rendered astronomically unlikely given evolution’s non-truth tracking selective constraints in forming our moral judgements and attitudes. If you are interested in following this dialectic, I recommend beginning with Shafer-Landau R. (2012); or Wielenberg E.J. (2016) for an equally eloquent introductory overview. For the more philosophically technical and patient readers, the central text by which many are targeting their responses to is Street's (2006) initial debunking argument formulation – which is a very rewarding read! And lastly, to hear it from the horses mouth, I'd equally recommend jumping straight into Vavova's, most accessibly written, 2015 paper – in which respect the Philosophy Compass journal is always the most reader-friendly for the less exposed to academic philosophy.

[2] Naturally, we'll consider evidence to be both what is empirically and logically demonstrable, as evidence is typically presented in tandem with what is logical and empirical, and rarely one or the other. A mathematician, or seasoned Analytician might offer something purely logical; meanwhile a scientist, like the optometrist of the above example, will rely on both.


[3] Demonstrable covers evidence that might consist of rational-logical or mathematical proof,  as well as less abstract notions of evidence as material (objects, imaging, recordings, etc), whilst securing that both are reliable such that they are replicable and reproducible.




References:


Shafer-Landau, R. (2012). Evolutionary debunking, moral realism, and moral knowledge. Journal of Ethics and Social Philosophy, 7, 1–37. https://doi.org/10.26556/jesp.v7i1.68


Street, S. (2006). A Darwinian dilemma for realist theories of value. Philosophical Studies, 127, 109–166. https://doi.org/10.1007/s11098-005-1726-6


Vavova (2014). Debunking Evolutionary Debunking. Oxford Studies in Metaethics, R. Shafer-Landau (Ed.) 9, 76-101. https://doi.org/10.1093/acprof:oso/9780198709299.003.0004

 

Vavova, K. (2015). Evolutionary Debunking of Moral Realism. Philosophy Compass, 10(2), 104–116. https://doi.org/10.1111/phc3.12194

 

Vavova, K. (2021). The Limits of Rational Belief Revision: A Dilemma for the Darwinian Debunker. Noûs 55 (3):717-734.  https://doi.org/10.1111/nous.12327


Wielenberg E.J. (2016). ‘Ethics and Evolutionary Theory.’ Analysis 76(4), 502–15.

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