My friend Ed Gibney has written on each and every one of the thought experiments in Julian Baggini’s, The Pig That Wants to Be Eaten: 100 Experiments for the Armchair Philosopher. Gibney has also summarized his own 100 blog posts on Baggini’s 100 thought experiments in “What I learned from 100 Philosophy Thought Experiments.”
(Here is his summary of, and commentary on, Baggini’s thought experiments dealing with metaphysics. It follows from a previous post on worldviews. I have added my own brief reflections at the bottom of the page.)
From Ed Gibney’s blog, reprinted with permission.
What do I know? From #1 The Evil Demon, we cannot be absolutely certain of anything. #62 I Think, Therefore? shows that not even cogito ergo sum is a bedrock. Everything is uncertain and all knowledge is probabilistic. In #41 Getting the Blues, we saw that knowledge comes only via sensory experiences. We haven’t found any exceptions to this. This is reinforced in #13 Black, White, and Red All Over, where the physical nature of the universe creates an epistemic barrier to our knowledge. As a consequence of all this, #63: No Know shows that since we can never be certain that any TRUTH will remain unchanged in a changing universe, our cosmological revolutions need to sink into our epistemological understanding. Knowledge can only ever be: justified, beliefs, that are surviving. For such an evolutionary epistemology, all theories are “true” only provisionally, regardless of the degree of empirical testing they have survived. #73 Being a Bat showed that this evolutionary perspective provides a clear and interlocking set of beliefs that consistently come together to help solve the most fundamental questions of philosophy.
What about the knowledge of others? What do they know? And what can we ever really say to one another? #47 Rabbit! showed that we cannot know for certain that we are talking about the exact same thing whenever we talk to someone, in this language or another. Through #74 Water, Water, Everywhere, we see that the meaning of our words evolves as more information comes in. This is why the many and varied efforts of philosophers of language to find logically perfect and universal definitions of meanings are doomed to failure. There is hope, however. #23 The Beetle In The Box shows that we cannot know what is inside other minds, but our shared evolutionary history makes it highly probable that there is much in common. For example, in #59 The Eyes Have It, vision has shared the same chemical basis across the entire animal kingdom for over a billion years. We can’t Know with a capital K what others see, but it is extremely likely to be the same as what we ourselves perceive. In #19 Bursting the Soap Bubble, our shared evolutionary history shows that we all see the world similarly, but we must still be open to hearing others’ views and change our minds when it is justified. In fact, according to #3 The Indian and the Ice, we absolutely must change our minds, although only when it’s appropriate.
How do we know when it’s appropriate to change our beliefs? In #40 The Rocking-Horse Winner, we see that knowledge cannot be generalized from prior perceptions, nor predicted using the assumption that the universe is uniform. The best we can do is prove through falsification via the scientific method what does not work. In the face of this, #28 The Nightmare Scenario shows that there is a big difference between productive speculation, which is the hallmark of good science, and pernicious speculation that specifically eliminates the possibility of testable hypotheses. As shown by #51 Living in a Vat, there are infinite unfalsifiable notions about reality so none of them are more probable than any other. Therefore, none of them ought to have any bearing on our behavior. In fact, as shown by #81 Sense and Sensibility, if a belief is completely unscientific because it is unfalsifiable, then the burden of proof for such strange ideas must fall on the person advocating the notion, since such things cannot be disproven, and there are infinite such nonsenses (like Bertrand Russell’s teapot orbiting the sun, the flying spaghetti monster, or all historical notions of God).
To reiterate, according to #93 Zombies, we cannot use our general epistemological uncertainty to arrive at any epistemologically certain statements, such as “physicalism is true” or “physicalism is false.” Philosophers seem to enjoy speculating about the unknown and fighting about what may or may not be there while the evidence is gathered by scientists, but none of these merely potential occurrences have any weight whatsoever to actually affect our current knowledge. They are observations with an n of zero.
So now that we have some knowledge—justified, beliefs, that are surviving—what can we do with this?
My brief reflections – I agree with Gibney’s epistemological fallibilism/skepticism modified by the view of the provisional nature of all truth. I would only emphasize that this does not imply relativism, as the provisional truths of science are often supported by mountains of empirical evidence. The best a rational person can do, as Locke and Hume taught us, is proportion their assent to the evidence.
(Next up – the thought experiments dealing with logic.)