by Thomas Raleigh

Here are 2 very natural ideas about conscious experiences:
(1) They are in some deep, interesting sense private.
(2) Nevertheless, different subjects can have qualitatively similar experiences.
 
I think that these 2 ideas are in tension. If we take seriously the idea that it is metaphysically impossible for any other subject to experience my phenomenal experiences, then the notion of phenomenal similarity across different subjects will not be well defined. And the reason for this is that the very idea of a phenomenal or appearance property – how something looks, feels or appears – is an inherently relativistic notion. That is: how something looks/feels/appears is always relative to some kind of subjective viewpoint or sense modality.
 
What is the relevant sense of ‘private’? Roughly: it is metaphysically impossible for anyone else to ‘directly’ experience my token phenomenal states/property instances. (Slightly less roughly: it is impossible for the token phenomenal features which constitutively form my stream of consciousness, to likewise constitutively figure in anyone else’s stream of consciousness.)
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A traditional sort of scepticism raises the worry that we cannot ever know whether our respective private features are qualitatively the same – maybe your experience when looking at a ripe tomato is privately very different from mine; maybe your sensations when you bang your funny bone are quite different to how banging my funny bone feels to me; maybe, despite your fluent talk about experiences of various kinds, you actually have no inner conscious life whatsoever; and so on.
However, even allowing that this sort of sceptic may have a point, the following thought can seem very plausible: ok, perhaps I cannot be sure that your private stuff is the same as mine. But so long as it is in fact the same (and we both suppose or believe this to be so even if we may not be able to know it), then we can at least still successfully communicate and understand each other’s claims about our respective private stuff.

But notice that this line of thought relies on the second idea, above: that there can be facts, even if they may be unknowable, concerning inter-subjective phenomenal similarity. And this has been denied, at one time or other, by quite a few distinguished philosophers – including Frege, Schlick, Shoemaker and Stalnaker.
 
What is the problem then with the idea that 2 private phenomenal items, from 2 different subjects, could just naturally be similar – irrespective of what either subject can know or judge, or their dispositions to classify them and so on?

​Jennan Ismael makes a comparison with the notion of simultaneity in relativistic physics: there can be facts about temporal relations between 2 events within a spatial frame of reference. But when the 2 events are specified as belonging to different frames of reference, there is no fact as to one being earlier/later than the other. Likewise, given a model of experience which satisfies (MP), sameness or difference in the phenomenal appearance/feel of two private items/features may be well-defined relative to a particular subject’s private domain. But if the experiential elements in question belong to two different metaphysically private viewpoints, then any comparison of phenomenal appearance will not be well-defined. Just as there is no such thing as simultaneity simpliciter, but only relative to a specific frame of reference, there would be no such thing as phenomenal similarity simpliciter, but only within a specific private viewpoint.

One more comparison: John Divers has recently raised the following problem for Lewisian realism about possible worlds. If the truth of our modal claims is supposed to be explained by the existence of counterparts in distinct possible worlds, and those possible worlds are not spatio-temporally related to each other (i.e. spatio-temporal relations only obtain within individual possible worlds), then we face a problem with counter-factual claims like the following:
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 ‘Usain might have been taller than he actually is.’

For the truth of such a claim is supposed to require the existence of a counterpart of Usain in some other possible world who is ‘taller than’ the actual Usain. But Usain in the actual world and Usain’s counterpart in some other possible world do not stand in any spatial relation; a fortiori they do not stand in the ‘taller than’ relation. In the absence of any possibility of actual-Usain and counterpart-Usain having their heights defined relative to a common spatio-temporal framework, we cannot make sense of claims that their respective heights are ‘the same’. Not only is it impossible for actual-Usain and counterpart-Usain to inhabit each other’s spatio-temporal domains, it is also impossible for any other item to function as a benchmark or ruler by which to meaningfully compare their heights – as it is metaphysically impossible for any item to figure in more than one Lewisian possible world.
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Likewise, I am suggesting, assuming the metaphysical impossibility of my experiencing your private phenomenal items, or vice-versa, there is a lack of any common ‘appearance-space’ in which two items from distinct domains could have their subjective feels/appearances meaningfully compared as being phenomenally similar or different. Not only is it impossible for either of the two items in question to appear in the other’s private domain, it is also impossible for any other possible item/feature to serve as a phenomenal benchmark or standard in common to both private domains – as it is impossible for any item/feature to appear in more than one private phenomenal domain.

That is just the briefest sketch of the issue. But so what to do? I suggest that in order to hold onto the idea that we can have naturally similar phenomenal experiences, we should give up on the idea that they are metaphysically private – an idea that is in any case in tension with the physicalist idea that phenomenal experiences are ultimately just physical events/processes in the brain. There is nothing metaphysically private about the physical events and processes in a brain, which can be studied using 3rd-personal scientific methods just like other physical stuff. Indeed it seems plausible that it is precisely this supposedly special and unique conscious access we each have to our own sensations, mental imagery, innermost thoughts, etc. that provides one of the main motivations for dualism. As John Wisdom once remarked: “The peculiarity of the soul is not that it is visible to none but that it is visible to one”.

Taking seriously the idea that phenomenal similarity is always relative to a subjective viewpoint or appearance space – just as simultaneity and shape are relative to an observer’s frame of reference – thus gives us a reason to reject the perennially attractive idea that our conscious experiences are metaphysically private. But of course, others might want to jump the other way and hold onto phenomenal privacy at the expense of inter-subjective phenomenal similarity. The worry then is that this would make our privately defined phenomenal concepts incommunicable – but that will have to be a topic for another occasion.

If you are interested in the issues raised in this post, look out for Thomas' forthcoming article 'Phenomenal Privacy, Similarity and Communicability', which will be published soon in Ergo. ​

By Victoria Lavorerio

This summer term, Martin Kusch, philosophy professor and principal investigator of the “Emergence of Relativism” research project, held a Master-level research seminar (or "Forschungsseminar") in the University of Vienna devoted to epistemic relativism. The course explored recent proposals and criticisms of epistemic relativism, and it culminated on Monday, 27th of June in an all-day workshop in which the students presented their tentative results. The students’ presentations covered a range of issues and positions studied throughout the course, as well as some independent explorations of recent and not so recent relativistic proposals.

The day started off with presentations dedicated to Sankey’s reconstruction and critique of epistemic relativism. Olga Ring took issue with Sankey’s strategy to refute epistemic relativism; not only is his naturalistic stance (construed as an epistemic norm) also vulnerable to the problem of the criterion, but it is in tension with his brand of particularism. Relatedly, Richard Bärnthaler argued against Sankey’s claim that naturalism, but not relativism, can provide justification in an objective sense. Drawing from Galison’s work, he considered objectivity as a (historically-relative) epistemic norm, and argued that the empirical investigation behind the naturalistic approach uses the very epistemic norm it is supposed to evaluate. In his presentation, Jesse de Pagter turned to Evans-Pritchard’s study of the Azande to discuss the validity of the Equal Validity claim, which Boghossian and Sankey advance as an important feature of epistemic relativism.
 
Soheil Human’s talk was inter-disciplinary in nature, as he discussed how the predictive processing theory in neuroscience can contribute to MacFarlane’s criticism of Boghossian’s dismissal of “absolute relativism”. Also contra Boghossian, Tom Fery argued that there are ways to motivate relativism via the encounter of a different epistemic system, such as rejecting the claim that such system has to be impressive, or actual, or (which he deems more promising) by exploring the possibility that the two epistemic systems are on a par. Anne-Kathrin Koch’s talk asked the metaphilosophical question of what the disagreement between relativists (represented by Bloor) and absolutists (exemplified by Boghossian) is really about. After exploring the many facets of the contention, she advanced the hypothesis that what really is at stake is two different pictures of what epistemology is and should do.

The following panel explored the relations between relativism and disagreement. Lucas Smalldon discussed the famous disagreement between Bellarmine and Galileo, arguing that one shouldn’t ask who is more justified, but rather who is more rational. By using an error-correcting orientation, he argued that Galileo’s explanation fared better, and thus judging it to be a faultless disagreement is mistaken. In his presentation, Clemens Loidl presented Hazlett’s relativized entitlement to trust a source as a device to deliver mutually recognized reasonable disagreement; he then explored its potential to respond to Boghossian’s critique of faultless disagreement. I, Victoria Lavorerio, argued against Hales’s claim that relativism is a promising resolution strategy in cases of irresolvable disagreements, by analyzing the demands such strategy makes on the disputants, and why they cannot be met. Closing the panel, Christoph Lernpaß focused on the evolutionary debunking argument from disagreement and its connection to moral relativism. He argued that Mogensen’s distinction between “arbitrarily absent” and “merely possible” does not pick up only the epistemically relevant disagreements.

Opening the final panel of the day, Henriikka Hannula aimed to expand Sharon Street’s relativism about normative reasons to include the agent’s cultural and social context, as well as her practical reasons, which underpin normative reasons and are not necessarily about getting true beliefs. In his contribution, Jakob Schott compared Rorty’s and Boghossian’s interpretations of Kuhn, while claiming that the latter was the least comprehensive and charitable. Taking Hartsock’s Marxist standpoint theory as an example of feminist epistemology, Karoline Paier asked which kind of relativism would help the feminist’s advantage thesis the most. After reviewing some possibilities, she concludes that Stanley’s interest-relativism looks the most promising. Finally, Daniel Eduardo Marante Mendoza took Bloor's relativism of content and meaning and placed it against Boghossian’s taxonomy and subsequent critique of different kinds of relativism to see whether (and) they applied to Bloor’s theory.

I hope I have done justice to the enjoyable and busy day we had, exploring and discussing both classical and unexpected issues related to epistemic relativism.