The Brain:How do
we know that other
people have thoughts?
In this essay, I will explore the 'Other Minds Problem'(1). This is the phiosophical problem that asks how we can know that other people have conscious experiences, like pain, or emotions. In this essay, I will explore if it’s possible for us to know that other people have such conscious experiences at all.
Before we ask ourselves whether we can know that other people have conscious experiences at all, we have to back – track a little. We should first establish whether the outside world is knowable (directly or indirectly), and whether the outside world is of the form it appears to be. (2)
For the purposes of this essay, I will define:
A = We have knowledge of the Outside World (direct or indirect)
B = The Outside World exists as it appears
C = Other people have conscious experiences at all.
This will create four circumstances – A AND B, A AND NOT B, NOT A AND B, and NOT A AND NOT B – for us to test whether we can know C. For the purposes of this essay, we will assume that it is true that C, OR NOT C. In other words, people either have conscious experiences, or not.
A AND B
Should a scenario where A AND B were to arise, or we were to be reasonably sure that B is the case, we can instantly eliminate a range of alternative explanations to C. These include deities, deceptive demons, brains in vats, or other scenarios where other humans may not have conscious experiences because these assume the world doesn’t exist as it appears (i.e. NOT B). And, in such a circumstance, we would presumably come the closest to knowing C.
Instead of arguing C in the A AND B scenario, I’ll look at what the consequences would be, if you accepted NOT C in such a circumstance.
Certainly, not every behavior is predicated on a conscious experience. Sometimes people act out of instinct or habit. Or they act in a particular manner in spite of their conscious state in certain social circumstances; in spite of how they really feel(3). But to base a case of NOT C on this point would require two large generalizations. First, because some behaviors are acted out by people based on habit or instinct, all behaviors are. Secondly, because you do this some of the time, all people except for you do it all the time. Quite a leap.
To argue for C at this point would be to take an overly simplistic view of human nature. If you make a NOT C argument, you also have to explain what becomes some thoroughly bizarre phenomena.
For example, the hallmark of a good actor, pro wrestler, soccer player, or politician is that they can make you believe they are having a different conscious experience to the one they are really having. You could even define an actor as a person whose profession involves convincing others that they are having conscious experiences (and are in emotional states) other than the one they really are. If no-one else has ever had a conscious experience underneath the part they are portraying, by definition you are the only person in the history of the universe capable of acting! Quick, call the Academy, they owe you several years worth of overdue awards by default!
Another obvious problem a NOT C argument would have to overcome is the fact that the term “conscious experience” exists. If you were to accept that other people don’t have conscious experiences at all, then the term “conscious experience” would have been invented by someone, who never had a conscious experience, to describe something they didn’t have, prior to the birth of the first, and only, person in history to have had a conscious experience (i.e. you).
Oprah Winfrey, who has never had a conscious experience, would have become a billionaire by hosting a TV program, where people who don’t have conscious experiences, watch people who have never had conscious experiences, describe conscious experiences they’ve never had.
Advertising executives, who have never had a conscious experience, create advertising based on appeals to emotion in the hope that people who have never had an emotion – or any other conscious experience, will be moved by nonexistent emotions and conscious experiences to buy products with no non-emotional redeeming value.
Right now, you would therefore be reading an essay about conscious experiences by someone (i.e. me) who has never had a conscious experience. And before you were born, philosophers have been dealing with the “Other minds problem” where philosophers who have never had conscious experiences are trying to rationalize how other people who don’t have conscious experiences have conscious experiences.
Sure, a computer or robot could do the above, if they were pre-programmed to.(4) But if humans are like this, who programmed humans to act in a manner similar to a being that has conscious experiences, if not their own conscious experiences? Keep in mind the fact (in this circumstance) that B prevents us from invoking a ‘Not B’ argument.
Looking through the above examples, arguing NOT C seems almost contradictory, and even if this is not the case, an argument of Not (Not C) seems like a better explanation, and a lot less counter-intuitive, than Not C.
So, in standard form:
P1: IF (A AND B) THEN C OR (NOT C)
P2: NOT (NOT C) (Or ‘The best explanation is Not (Not C)’)
C.: IF (A AND B) THEN C (Or ‘IF (A AND B) THEN The best explanation is C’).
A AND NOT B
The next situation I want to test for is what would happen if we got to a point where A AND NOT B was accepted. In other words, where the outside world is known or knowable, but it is not how it appears.
In such a scenario, it would be more difficult to show C, but depending on the nature of what sort of world replaces B, C may well still be the best explanation.
Think about a scenario like The Matrix(5) – where real people interact in a virtual universe, or The Truman Show(6), where a person’s life is played out on a giant soundstage – the other people who a person in either environment interacts with do have conscious experiences. If you could somehow find out that you lived in such a NOT B circumstance, an argument for NOT C would yield similar results to the argument above, where B was assumed to be true.
With brains in vats, a deceptive demon, or deity universe, the question becomes does the mad scientist, robot, deceptive demon, or deity behind the people in the universe of the mind have conscious experiences? If that is the case, then the force behind the deceptions has conscious experiences, and therefore in interacting with other people you are interacting with a person that has a conscious experience behind it. Keep in mind, though, that may not necessarily be the case for such examples.
In this NOT B instance, we cannot be as certain of C as we could be if B were known. There are certainly a range of possibilities where NOT C is the case if NOT B, but this is far from necessarily true.
However, there’s a big problem with this scenario: how would you know A AND NOT B for certain? You may well have to find out by appearances; or sense data; that all appearances or sense data you have ever received is wrong. If someone came along and said that all your sense data was wrong and they had experienced the “fact” that the world really wasn’t as it appeared, you would probably find a better explanation for this person’s claims. Like they smoked something other than tobacco this morning(7). Or the cheese had slid off their cracker. And they would need a darn good case to show they had a better explanation.
So A AND NOT B seems implausible.
NOT A AND B, OR NOT A AND NOT B
Where it becomes a lot more difficult is when we get a scenario where NOT A (combined either with B or NOT B). In other words, where the outside world and its nature is unknowable. And that is because, without being able to know A, we are not able to know whether, in the world we live in, either B or NOT B is true. Or, more precisely, if NOT B is true, we don’t know the nature of the universe and whether we either are interacting indirectly with humans with conscious experiences, or people who have a conscious experience behind them, or whether other people exist at all. And in such a circumstance, C OR NOT C may well be un-knowable.
WHERE DOES THIS LEAVE US?
So, the critical point in this discussion is A. Knowing A is critical in deciding if we can or can’t know whether C, or NOT C. The nature of the world determines whether C or NOT C is true.
You will notice I have used a deductive argument to look at what happens at the four extremes of A and B, and if each of these extremes are possible. But the reason ‘other minds’ is being discussed, as an open epistemological question, is precisely because there is no necessary truth that has been uncovered that means that A AND B must be true. So what we are left with is an inductive argument to the best explanation(8) that come close to one of the 4 poles, yet never quite reach it.
And, as it stands, the best explanation is A AND B(9). Therefore, as demonstrated above, if A AND B THEN C, we can know C as much as we can know A AND B.
IN CONCLUSION (Standard Form):
P1: IF (A AND B) THEN C OR (NOT C)
P2: NOT (NOT C)
C1.: IF (A AND B) THEN C
P3: IF (NOT A AND B) OR (NOT A AND NOT B) THEN C OR NOT C
P4: IF B THEN C
P5: B OR NOT B Is Unknowable
C2.: C OR NOT C Is Unknowable
C1: IF (A AND B) THEN C
C2.: C OR NOT C Is Unknowable
P6: The Best Explanation is (A AND B)
C.: The Best Explanation is C
(1) Oakley, Tim, PHI21CAS Lecture, Tuesday, March 30th, 2004, Bundoora University
(2) Whiteley, C.H., “Epistemological Stratergies”, p. 25, Mind, 1969, p. 25.
(3) Lecture, Op. Cit., Monday, April 15th, 2004.
(4) Lecture, Op. Cit., Tuesday, March 30th, 2004.
(5) Wachowki, Andy, and Wachowski, Larry (directors), “The Matrix”, 1999, Warner Brothers.
(6) Weir, Peter (director), “The Truman Show”, 1998, Paramount.
(7) A plausible explanation if their “real world” involved Gremlins swimming in their sink.
(8) Lecture, Op. Cit., Monday, March 29th, 2004.