How do philosophers respond to global skepticism?

Question

I saw a video of a philosopher (Robert Audi) who said that common sense is the best response we can give to global skepticism. I would agree, but it's not clear to me what the nature of common sense is. Is it a set of intuitive beliefs?

I used the adjective "global" because I'm interested in understanding how we form beliefs regarding the reliability of our faculties (memory, perception and reasoning) from which any belief arises.

I also read Audi's book on epistemology. He talks about prima facie justifications that, according to him, are enough to hold a confidence level regarding a certain proposition P. Are prima facie justifications the basis of common sense? In what way prima facie justifications differ from warrants in Reliabilism?

Overall, if any, what is a successful response to global skepticism?

Answer 1

The bottom line is that, like knowledge [commonly defined as "warranted or justified true belief"], to be "interesting" [sticking to your lecturer's postmodern argot], skepticism must also be justified, be warranted [using the non-postmodern argot]. That is, my claim to know, or doubt [be skeptical about] claim C is justified/warranted, by x,y,z...

Roughly following this model, I shall answer your query (pertaining the relationship between universal/absolute skepticism and "common sense") simply by citing a summary of Roderick Chisolm's essay Commonsensism:

‘Commonsensism’ refers to one of the principal approaches to traditional theory of knowledge where one asks oneself the following Socratic questions: (1) What can I know?; (2) How can I distinguish beliefs that are reasonable for me to have from beliefs that are not reasonable for me to have? and (3) What can I do to replace unreasonable beliefs by reasonable beliefs about the same subject-matter, and to replace beliefs that are less reasonable by beliefs that are more reasonable? The mark of commonsensism is essentially a faith in oneself – a conviction that a human being, by proceeding cautiously, is capable of knowing the world in which it finds itself.

Any inquiry must set out with some beliefs. If you had no beliefs at all, you could not even begin to inquire. Hence any set of beliefs is better than none. Moreover, the beliefs that we do find ourselves with at any given time have so far survived previous inquiry and experience. And it is psychologically impossible to reject everything that you believe. ‘Doubting’, Peirce says, ‘is not as easy as lying’. Inquiry, guided by common sense, leads us to a set of beliefs which indicates that common sense is on the whole a reliable guide to knowledge. And if inquiry were not thus guided by common sense, how would it be able to answer the three Socratic questions with which it begins? [https://www.rep.routledge.com/articles/thematic/commonsensism/v-1/sections/critical-commonsensism-a-systematic-treatment.]

Wishing to interrogate the issue further without venturing to far into realism's ontology/epistemology conundrum, you may also wish to peruse the writings of C.S. Pierce and his critical commonsenseism, to some extent exemplified by the dictum that "The test of doubt and belief is [the habit of] conduct," and observation that:

No sane man doubts that fire would burn his fingers; for if he did he would put his hand in the flame, in order to satisfy his doubt. There are some beliefs, almost all of which relate to the ordinary conduct of life, such as that ordinary fire burns the flesh, while pretty vague, are beyond the reach of any man’s doubt.

Here Pierce anticipates the later Wittgenstein's notion of "hinge propositions" in On Certainty [essentially meditations about knowledge and doubt]:

If you tried to doubt everything you would not get as far as to doubt anything. The game of doubting itself presupposes certainty. [OC, section 115]...the questions that we raise and our doubts depend on the fact that some propositions are exempt from doubt, are as it were hinges on which those turn. [OC, section 341.] That is to say, it belongs to the logic of our scientific investigations that certain things are in deed [italics Wittgenstein's, bold mine] not doubted. [OC, section 342.]

ADDENDUM: In response to comments, allow me to add the following: Among the rules of the epistemic language game (as opposed to, for instance, the religious language game) governing when it is meaningful to say that someone knows x, it is said that the person who claims to know x must be able justify, or offer reasons in support/favor of x. And, further, that these reasons must themselves be “more certain” than x. Same goes for skepticism. The same rules would require that in order to meaningfully use ‘to doubt,” one must have grounds for, be able to justify some particular doubt that x.

That this method potentially leads to an infinite regress (see Agrippan or Münchhausen trilemma) is no reason to abandon it tout court. It is simply our epistemological condition. (See Wittgenstein’s On Certainty where, as noted above, he defends his notion of indubitable Hinge Propositions. ) In the context of rule following, Wittgenstein says If I have exhausted the justifications, I have reached bedrock and my spade is turned. Then I am inclined to say: "This is simply what I do." Philosophical Investigations § 217. Which brings us back to Pierce's claim, mentioned above, that beliefs and doubts can at bottom be characterized as "habits of conduct."

Answer 2

I haven't read Audi, but I'll put this extended comment on 'common sense' out for consideration...

All of philosophy begins at prima facie experience. We have prima facie experiences we attribute to the external world, usually derived from our physical senses; we have prima facie experiences we attribute to an internal, subjective world, such as thoughts, emotions, and urges. It's these experiences that become the content and focus of any philosophical investigation. I'd even go so far as to suggest that the empiricist/rationalist divide is a long-running dispute about whether prima facie sensory experience should be collapsed into our subjective world, or whether our prima facie subjective experience should be collapsed into the external world, but that strays a bit off topic.

There are effectively three approaches in philosophy to dealing with prima facie experience:

1. To assert that our prima facie experiences have a direct connection to ontological features of an objectively 'real' world. For instance, if we see the sun rise in the East, we might conceive that as the sun literally rising, or as the Earth rotating, but the Sun, the Earth, and their relative motions are concrete phenomena existing independent of any experiencer. Most of what we typically call 'empiricism' falls within this approach.
2. To assert that our prima facie experiences are corrupted, partial, or mediated representations of phenomena that lie outside the capacity of the human mind or sensory apparatus to process. This lies behind most forms of idealism: e.g., we can invoke a concept of an idealized human form, or of an infinitely long number line; these help us establish certain useful principles even though we can't perceive the thing itself.
3. To assert that our prima facie experiences are merely reflections of the mind's tendency to structure incoming perceptual noise into objects, structures, and events that are arbitrary aside from their functional utility. A lot of language theory falls into this approach when it suggests that (say) the concept 'table' is socially/linguistically constructed: 'table' is defined circularly as any object that fulfills the functions and qualities we expect of a table, and that if we had no concept of 'table', tables would not exist.

Just as there are three basic approaches to dealing with prima facie experience, there are three basic attitudes one can adopt towards these approaches:

• Credulity: accepting prima facie experience as is, without reflection
• Scientific skepticism: accepting prima facie experience as is, while questioning the underlying phenomena that produce those experiences
• Cynicism: questioning prima facie experience directly, rejecting the idea that it necessarily or meaningfully reflects any underlying causation.

People tend to mix and match these attitudes by context; they are less stable than the earlier-mentioned approaches. For example, it's easy to find (say) empiricists who accept some physical principles entirely at face value, view others with a scientifically critical regard, and dismiss any experience they consider subjective as a meaningless artifact of some hitherto unknown physical property. But regardless, we have to take one or the other of these attitudes whenever we are confronted with prima facie experience.

This is where the idea of 'common sense' comes into play. When we have an experience, we cannot say "I did not have that experience." Instead, we are called on to find a suitable explanation for that prima facie experience. If someone sees a ghost, or a UFO, or whatever bugbear you like, they are not in a position to deny the experience. They can take it at face value, question it to find a more 'rational' explanation, or decide they were having a dream or hallucination, but they cannot reject the experience itself. Common sense, then, is that act of fitting that experience into a consistent, coherent, and comprehensible worldview. It has less to do with how we think about the experience itself than with how we manage and integrate that experience within our worldview.

Skepticism in the 'global' sense is a useful and interesting thought experiment, but it intrinsically lacks common sense because it explicitly destroys the possibility of any consistent, coherent, and comprehensible worldview. The only reason to engage in global skepticism — be it Cartesian decomposition or linguistic deconstruction — is to expose the inner workings of a worldview so that it can be put back together in some form that better satisfies common sense. Without that subsequent reconstructive step, 'global' skepticism leaves us hanging in the void, which is not (generally speaking) where we want to be.

Unfortunately, 'global' skepticism of this sort is also a strong defensive position for anyone who feels under attack: a stubborn "I may be wrong but you're not right" posture that can be difficult to overcome. It is a disengagement from reason and common sense, and unless those capacities are re-engaged no movement can be expected.

Answer 3

GE Moore, Moorean facts. “Here is one hand”. https://en.m.wikipedia.org/wiki/Here_is_one_hand. There is a paper there in “External Links” you may want to read by Thomas Kelly.

Answer 4

I saw a video of a philosopher (Robert Audi) who said that common sense is the best response we can give to global skepticism. I would agree, but it's not clear to me what the nature of common sense is. Is it a set of intuitive beliefs?

No, it is very rational. But in order to see it, we need to take a step back out of the epistemological haze; and maybe even to step back further out of philosophy... as it exists now, anyway.

We need to take a look at the big picture and ask ourselves, "What is the point?.." Why do we need philosophy in the first place? To know the nature of truth? -- but why? Why do we need to know it? Or the nature of reality?

More than two millennia ago Socrates, apparently, found himself in similar circumstances when he felt the needed to remind his interlocutor:
  "Do not take what I say as if I were merely playing, for you see the subject of our discussion -- and on what subject should even a man of slight intelligence be more serious? -- namely, what kind of life should one live?.." -- Plato, "Gorgias"

In other words, the ultimate question, therefore, is never about some abstract knowledge, like the nature of truth. Rather, it is about its practical implications -- the latter being more important than the former. It means that, sometimes, the most rigorous model and, technically, the most accurate answer will be rejected simply because its inferior practical implications.

The above concept is also known as the Streetlight Effect, so named after a parable of an emphatically rational drunkard, who, after losing his keys the park, was found searching for them under street lights.

Here is a video of a crow, apparently relying on the "streetlight effect" to start solving the puzzle before he knew the full solution.

Back to global skepticism

I'll focus the Cartesian model, specifically, because it is the most rigorous theory of truth, reality, and knowledge. According to it, we cannot know anything beyond the only knowledge absolutely must have -- that of our own existence. And, strictly speaking, this is it.

Unfortunately, we cannot accept it, even tho it is perfectly accurate, because of its practical implications. Having no knowledge of the outside world leaves us with no freedom to do anything. There would nothing to do until we die from thirst or sooner.

That leaves us with Søren Kierkegaard's leap of faith as the only way out. We have to come up with assumption(s) that would let us develop a more useful theory of truth.

As it turns out, one assumption is all it takes: we assume the existence of one and only reality, explainable through lógos, or logic and reason, which we all share and are a part of (a.k.a. the one and only God of pre-civilization, fully rational humanity).

The above makes for the first premise, which a fully rational system of beliefs can be inferred from trough logic and reason.