Should we believe the universe exists?
TAM quoted Jerry Coyne as asking “what conceivable observation about the universe could convince you that God does not exist?” I responded by attempting to draw out the principles lying behind Coyne’s question. And I came up with the following:
(a) If there are no conceivable observations of the universe that could convince you that X doesn’t exist, then it is silly to believe that X does exist.
(b) If there are no conceivable observations of the universe that could convince you that p is false, then it is silly to believe that p is true.
I then provided three examples of things that people believe exist which they do not accept based on observations of the universe: (P1) other universes, (P2) abstract objects, (P3) a form of the good. But surely belief in these things is not “silly” and so we should reject (a) and (b).
Robert demurs. He likes (a) and (b). And he defended them by arguing of (P1), (P2) and (P3) that
“I could believe them AND conceive of observations in the universe that would convince me I was wrong. If there is nothing in the universe that could convince me I was wrong about P, then there really is something askew in my epistemology if I won’t recognize that and re-calibrate my beliefs about P.”
There are many issues here including the following: (i) how does one define an “observation” and (ii) what is meant by “convince” (e.g. rationally persuade)? But rather than further the discussion on (P1-P3) I want to keep the main thing the main thing and that is the status of (a) and (b).
With that in mind, let’s substitute “the universe” for X in (a):
(a) If there are no conceivable observations of the universe that could convince you that the universe doesn’t exist, then it is silly to believe that the universe does exist.
Next, let’s slot “the universe exists” into p in (b):
(b) If there are no conceivable observations of the universe that could convince you that “the universe exists” is false, then it is silly to believe that “the universe exists” is true.
If you accept (a) and (b) then you cannot rationally believe the universe exists because there are no conceivable observations that could show the universe doesn’t exist.
Now that really is silly.
[Footnote: just for fun this afternoon ask yourself what it would take to convince you that you don't exist. If you can't come with something then according to these principles it is silly to believe you do exist. Now that might sound idiotic, but there is a potential application. The next time a police officer pulls you over for speeding, tell him that according to (a) and (b) he shouldn't believe he exists. Then you play your trump card: "Now officer, if you can't believe you exist, how can you believe that you should give me a ticket for speeding?" Bingo!]
]
Tags: defeaters, epistemology, evidence, Jerry Coyne, justification, rationality
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David Parker says:
Saturday, July 16, 2011 at 5:07pm
The Aristotelian might answer Coyne’s question as follows: “if the universe could be observed containing an unexplained–or uncaused, or sufficient-reason-lacking, whichever you like–event, then that would convince me that God does not exist.”
My bigger problem with Coyne is that he is using a conceivability argument…but wait…aren’t we constantly told that this argument style is weak? Recall prior discussions on this blog about the ontological argument or more importantly actual infinities! And yet here we are entertaining a metaphysical thesis about the universe derived from our conceptions of things in the universe. Tsk tsk! Conceptual analysis is either off limits or it is not.
Beetle says:
Saturday, July 16, 2011 at 5:10pm
I have to start with my last comment when you recently discussed this: Do you agree with Coyne that his two questions are equivalent? If not, we must take a step back because transmogrifying his second question into your (a) and (b) forms has this prior dependency.
Robert says:
Saturday, July 16, 2011 at 5:49pm
Randal, you are so much fun! Let me think about this. If I have anything decent to say, I’ll post it here.
Robert says:
Monday, July 18, 2011 at 12:33am
Randal, I’m going to expand on my comments about infancy:
When I was an infant, I was unaware that the universe existed. At some point, I learned that it does.
How did that happen? Did I randomly pull this idea out an infinite-belief-space and just get lucky that everyone around me happens to share the same belief? No. There were experiences and – dare I say evidences that led me to such a crazy conclusion; they are shared by everyone I know.
When I look back on the entangled experiences that led Robert[infant] to grow up believing in the existence of the universe, I can start to construct a storyline where Robert[infant] would have learned otherwise. Granted, that story is going to be really freaking weird, but potential weirdness should not distract from my main point (which I’ll label P-AWESOME).
P-AWESOME: My mind tries to model reality, and as far as I can tell, it does this with the input of external influences. The state of my mind is based on waking up here, now, Earth, 20th and 21st centuries CE. I don’t know where else I could have been born, but that does not make my belief in the external world unconditional. My belief *was* and *is* conditional based on experiences I have had. Unconditional facts are not the same as unconditional beliefs.
This goes back to Yudkowsky’s example on 2+2=3. I’m not sure you understand it.
randal says:
Tuesday, July 19, 2011 at 1:56pm
Robert, what relevance has your account have to an idealist like George Berkeley? He can explain to you that ll the *evidence* you think you have for an external world is no evidence at all. My rebuttal was intended to illustrate that Coyne’s principles are obviously false. I think I’ve done that. If you want to propose other principles I’d be interested in considering them.
Robert says:
Tuesday, July 19, 2011 at 4:04pm
And he would be wrong.
I will have to read up on Mr. Berkeley to confirm that, but if he believed experience of an external world is not really evidence of an external world, then he did not understand The Simple Truth.
The Simple Truth is a long story about why complete skepticism toward “truth” and “reality” is false. If someone wants to seriously deny the existence of an external world, Darwin will remove them from the gene pool. But the *truth* is that no one actually holds such skepticism (except when they want to conduct a thought experiment, engage an on-line debate, or write a philosophy paper).
P-AWESOME is not damaged by this false skepticism.
randal says:
Tuesday, July 19, 2011 at 4:07pm
“If someone wants to seriously deny the existence of an external world, Darwin will remove them from the gene pool.”
That’s not correct. Idealism in principle cannot be selected out by Darwinian processes because idealists believe all the same phenomenal experiences you and I do. They simply point out that those experiences don’t require an external world (true) and they believe there is in fact no external world (I believe falsely). But even if Darwinism was unfavorable to idealists, it wouldn’t mean idealism wasn’t true.
Robert says:
Tuesday, July 19, 2011 at 6:59pm
No. I think that’s false.
People have proposed ontologically basic mental things for a long time, but have they ever found evidence supporting this hypothesis? I see no evidence. On the other hand, there is plenty of evidence that experiences depend on a state of a brain. If your brain is changed to a very different state, you will have different thoughts, feelings, and desires. You will have different experiences.
So .. why should I believe in floating experiences that are disconnected from any external world? Why should I privilege a hypothesis that has no evidence and plenty of counter-evidence?
I currently think reductionism is true. What reasons do you have for thinking it is not?
randal says:
Wednesday, July 20, 2011 at 5:23am
“On the other hand, there is plenty of evidence that experiences depend on a state of a brain.”
But what is “your brain”? It’s merely more sense data or, as Berkeley would have said, “ideas”.
Berkeley didn’t believe the ideas were floating just anywhere. He believed they were the qualifications of minds in their various mental states. Robert, I’m tellin’ ya, you can’t win this one. There are idealists today who are tenured professors (Howard Robinson being a great example).
Robert says:
Wednesday, July 20, 2011 at 7:52am
Okay, I could now just say that tenured professors are sometimes wrong and keep saying I’m right without even knowing their arguments — but then I’d be like all the other Internet idiots who say such things.
I’m skeptical of idealism by how you have described it. In particular, I doubt any ‘hypothesis’ that has a mere possibility of truth in a thought experiment, but has no testable way of ever knowing if it actually is true. That’s what you are describing, am I right?
David P says:
Tuesday, July 19, 2011 at 4:15pm
Are you sure P-AWESOME avoids all skeptical concerns about the external world? Consider this argument:
1. All you know directly is how things seem to you. (How the external world affects your nervous system via the sensory organs).
2. If all you know directly are how things seem to you, then you can’t know how things really are outside of you.
Robert says:
Tuesday, July 19, 2011 at 6:35pm
Right. I don’t deny the Matrix as a *mere possibility*, but I also have no reason to privilege that hypothesis. If we go around rejecting things like P-AWESOME just on account of mere possibilities, Poor Mary would start to worry about being accused of random crimes – because it’s merely possible that she did it!
(Please excuse all the links to LessWrong, it’s just easier to link than restate those arguments I think are true.)
Beetle says:
Saturday, July 16, 2011 at 10:07pm
Coyne asks: If our universe simply reflected the action of pure naturalistic laws rather than the intentions of God, how would it differ from the universe we have today?
To which, Randal responds: If the universe that now exists were the result of natural laws then obviously it would not differ from the universe that exists since it would be that universe!
Coyne’s thought exercise seems very straightforward to me. Why do you only give it a strange response?
randal says:
Saturday, July 16, 2011 at 11:14pm
The question was poorly formed. Let’s call the actual universe U.
Scenario 1: God made U.
Scenario 2: God didn’t make U.
To ask how U would differ in these two scenarios makes no sense since U is the object in both.
Beetle says:
Sunday, July 17, 2011 at 1:32pm
The question is well formed, but thank you for illustrating the problem you think it has. Agreed, asking how U differs in the two scenarios makes no sense since U is the object in both. Of course, that is not the question Coyne asks!
Coyne asks, What aspects of U don’t reflect purely the action of naturalistic laws?
The thought exercise is about imagining U without God. Presumably, from a theist perspective, something would be different! Coyne asks how would U minus God differ from U? To the skeptic, it does seems that the equation is: U-God = U.
Presumably, you would argue that U-God = U’
Please describe how U’ might differ from U.
For example, DavidMStarling apparently thinks U’ would not have material anomalies which YEC could latch onto as evidence against mainstream science. I doubt that you find that particular line of argument persuasive, but I am quite interested in your response to Coyne. Maybe you think abiogenesis depends upon divine intervention?
David Parker says:
Sunday, July 17, 2011 at 1:48pm
“Presumably, you would argue that U-God = U’”
Wouldn’t most theists would say that U-God=Null, since they believe God created and sustains U?
If God exists, he is a necessary being. That means he exists in all possible worlds. So the theists should not be able to imagine any possible world where God does not exist.
Hence, we cannot imagine U-God. Coyne needs to hit the books. See Feser’s response here and here.
Beetle says:
Monday, July 18, 2011 at 11:50am
> Wouldn’t most theists would say that U-God=Null, since they believe God created and sustains U?
I would guess as much, so it seems like there should be some compelling God-specific examples between Null and U. That theists would like to give God credit for the big bang is obvious. But what since then? What about the sustains part? Is not the theist obligated to provide something? Is God require to ignite fusion? Does God’s will set the last decimal for the cosmological constant? Did God sleep for thirteen billion years until he deigned to give man a soul?
I don’t see how it follows that if God is a necessary being then we should not be able to imagine any possible world where God does not exist? You put the sentences next to each other, but you made no link between them. Your Feser URLs are interesting, but they are about the cosmological argument, and how Coyne doesn’t get it. Does Feser ever address these two questions of Coyne’s directly?
David P says:
Monday, July 18, 2011 at 4:38pm
I would guess as much, so it seems like there should be some compelling God-specific examples between Null and U. That theists would like to give God credit for the big bang is obvious. But what since then? What about the sustains part? Is not the theist obligated to provide something? Is God require to ignite fusion? Does God’s will set the last decimal for the cosmological constant? Did God sleep for thirteen billion years until he deigned to give man a soul?
There is a really compelling example…namely the fact of U. If U-God=null, and yet we find that there is a U…must I fill in the blank for you?
Try Googling for “divine concurrence” if you are interested in reading more.
Also, you should probably know that traditional theists believe that God is eternal and thus wouldn’t “sleep for thirteen billion years.”
Theists have provided plenty of responses. Check out your local library. You are too easily impressed by this Coyne garbage. Rise above it. Go read some Thomas Aquinas, for instance.
I don’t see how it follows that if God is a necessary being then we should not be able to imagine any possible world where God does not exist? You put the sentences next to each other, but you made no link between them. Your Feser URLs are interesting, but they are about the cosmological argument, and how Coyne doesn’t get it. Does Feser ever address these two questions of Coyne’s directly?
I’m sorry you don’t see this, but it simply follows from the definition of “necessary being” and “possible world” that we cannot conceive of a possible world where God non-exists, if God is a necessary being. Just because you can imagine something doesn’t mean you’ve imagined a coherent possible world. A possible world is a complete set of affairs…so we might imagine something that appears coherent but when combined with other facts that are true in that possible world…it ends up not so. So you are kind of right…you can probably imagine a “world” where God doesn’t exist…it just isn’t a “possible world”…because it is incoherent…at least as far as the theist is concerned who believes God is a necessary being.
Coyne’s inability to grasp the cosmological argument (and classical theism in general) is precisely what is at stake here. Feser doesn’t need to address Coyne’s problems directly. Coyne hasn’t raised a real objection. He’s simply showed us he doesn’t understand theism at the most basic levels.
Beetle says:
Tuesday, July 19, 2011 at 8:47am
> There is a really compelling example…namely the fact of U. If U-God=null, and yet we find that there is a U…must I fill in the blank for you?
Yes please. I am especially interested in your assertion regarding “sustains”.
> Also, you should probably know that traditional theists believe that God is eternal and thus wouldn’t “sleep for thirteen billion years.”
Okay, please provide examples of what God did between the big bang and mankind becoming conscious.
> So you are kind of right…you can probably imagine a “world” where God doesn’t exist…it just isn’t a “possible world””…because it is incoherent
Please explain or provide some examples.
> Coyne’s inability to grasp the cosmological argument (and classical theism in general) is precisely what is at stake here.
So you say, but you have not made the case.
> Feser doesn’t need to address Coyne’s problems directly.
He does if he wants to be credible. Besides, in the article you link to, Feser admits that not all good philosophers find the cosmological argument compelling.
> Coyne hasn’t raised a real objection. He’s simply showed us he doesn’t understand theism at the most basic levels.
If it is not a real objection, then why not engage in Coyne’s thought experiment? Can you at least articulate why Coyne thinks his two (very differnt) questions are a paraphrase of each other?
David Parker says:
Tuesday, July 19, 2011 at 11:44am
“Yes please. I am especially interested in your assertion regarding “sustains”.”
You can Google “divine concurrence” if you want to learn about it. Here are three basic positions:
1. God must make a causal contribution to every creaturely act, in order for him to perfectly know the future (Aquinas).
2. Divine concurrence is necessary, otherwise his (free) creatures could thwart his plans or goals.
3. Causation involves new things or properties coming into existence, so God must be the ultimate source of all new being.
“Okay, please provide examples of what God did between the big bang and mankind becoming conscious.”
Look into the distinction between eternal (timeless) and everlasting (for all times). It doesn’t make any sense to ask what an eternal being did between x and y. And your question is foolhearted anyways.
“Please explain or provide some examples.”
http://spot.colorado.edu/~heathwoo/phil3600/vaninwagen.pdf
Imagining a world is just putting images in your head alongside other propositions. You might imagine a vast, starry space and think “God doesn’t exist” at the same time. That isn’t a possible world.
“So you say, but you have not made the case.”
It doesn’t sound like you’d know the difference, Beetle.
Coyne admits he hasn’t read up on it…so that’s not even in question. And I’ve given examples of why his thought experiment is worthless for the theist. I’m not going to spend hours explaining this to you when you have the resources to look into it. Especially when you make an arse of yourself by asking for examples of what God did between the big bang…Maybe he worked on his tennis game?
Don’t be a troll. Arrogance and foolishness won’t reap any benefits. Better to simply admit you don’t understand what some theists think of God and his relationship to time…and then try to understand it.
“He does if he wants to be credible. Besides, in the article you link to, Feser admits that not all good philosophers find the cosmological argument compelling.”
Well of course they don’t, or else all good philosophers would be theists. I hope you don’t think that “admission” is at all striking.
Beetle says:
Wednesday, July 20, 2011 at 8:00am
You will understand if I find divine concurrence as unpersuasive as the cosmological arguments.
You have provided no tangible examples of how God sustains the universe, just your wishful thinking.
Fester admits that not all good theistic philosophers find the cosmological argument persuasive.
I ask again: Can you at least articulate why Coyne thinks his two (very differnt) questions are a paraphrase of each other?
David Parker says:
Saturday, July 16, 2011 at 11:00pm
Since God could easily create the exact same universe that purely naturalistic laws would produce…this is the dumbest thing I’ve ever heard.
You’d have to argue that God would do things differently…you know…miracles and such…but then you’re arguing that there are no miracles. So the argument achieves nothing…it just gets you back into a debate on miracles.
randal says:
Saturday, July 16, 2011 at 11:10pm
“God could easily create the exact same universe that purely naturalistic laws would produce…”
For sure. As I argue in Faith Lacking Understanding God could have providentially created a world with the initial conditions that would lead through natural laws to the resurrection of Jesus. The point, in that context, is that the concept of “miracle” has nothing essentially to do with the violation of a natural law or even special divine action.
davidstarlingm says:
Sunday, July 17, 2011 at 4:13pm
Forgive me for not understanding, but how exactly could natural laws lead to the resurrection of a dead person?
David Parker says:
Sunday, July 17, 2011 at 4:14pm
Particles could appropriately regroup with the same properties (what we might call “a living organism”) they had before.
David P says:
Wednesday, July 20, 2011 at 2:45pm
Silly Beetle. The point is that you don’t understand what divine concurrence is (but at least you will go far enough to ask someone on a blog to explain it to you). It is hardly surprising that you aren’t persuaded by something you haven’t taken the time to understand.
“You have provided no tangible examples of how God sustains the universe, just your wishful thinking.”
That is inaccurate. Let’s review: Theists who believe in concurrence would think that U-God is null. So this thought experiment is quite easy for them to render a verdict on, since without God there would be no U.
Now look at how you responded: “I would guess as much, so it seems like there should be some compelling God-specific examples between Null and U.”
Seriously? And then you kept harping on, asking about “sustains.” So I gave you a few summary points on it. And now you’ve come back with the charge that I’ve failed to do something I didn’t attempt to do. And on top of that you apparently think that something I’ve said is just my “wishful thinking.” And of course you are quick to remind me that you’re not persuaded by it (umm…duh you’re not a theist).
“I ask again: Can you at least articulate why Coyne thinks his two (very differnt) questions are a paraphrase of each other?”
Why should I chew your food for you? If you think the questions are distinct, show that they are…why would this be difficult for you to do? I was not actively reading the other thread, so I’m not sure why you’re so interested in whether these two questions mean the same thing. I certainly have little interest in proving to you that two questions mean the same thing. Maybe they do…so what?
Beetle says:
Thursday, July 21, 2011 at 8:47am
> It is hardly surprising that you aren’t persuaded by something you haven’t taken the time to understand.
You are so arrogant! Divine concurrence is not complicated, but it is unsubstantial. At least the cosmological argument has some logic to it. Divine concurrence is but a notion. Clever, and reassuring, but without rigor. Has your boy Feser taken it on?
> Why should I chew your food for you?
I think you (and Randal) have skipped over the most interesting part of the Coyne quote (emphasis added):
It is quite obvious to me why Coyne asserts that these two very different questions are paraphrases. Your previous comments demonstrate the point Coyne is making. Can you articulate why I think that is the case?
David Parker says:
Thursday, July 21, 2011 at 11:39am
If you’ll recall my three points, they didn’t reference divine concurrence simply as a concept, but used it in an argumentative context. And if you are confident that you now understand the concept (just note that I lack such confidence in you based on your behavior in this thread), why shouldn’t I play the Beetle game and ask you for explanation or examples? I’ll just be as ridiculous as you have been here, and say that your previous comments demonstrate my point. Can you articulate why I think that is the case? Hahaha. If you think my previous comments demonstrate Coyne’s point…you are definitely in another ballpark. No clue what you’re talking about.
Coyne looks to be saying the same thing to me. Nothing we’ve discussed in the thread here rests upon the distinction/ identity between the two sentences.
Here is a website I found recently with tons of introductory texts on the philosophy of religion. Given your interest in the subject, why not get better acquainted with it?
http://esotericonline.net/docs/library/Philosophy/
Beetle says:
Thursday, July 21, 2011 at 10:17pm
I hear you saying that Feser is silent on Divine Consensus.
I will crib from the punch line of a cartoon DavidStarling linked to recently.
If Divine Consensus has to do with reality, it is in the domain of science. (And you would be able to say something substantive about it.) If not, they why do we care?
> If you think my previous comments demonstrate Coyne’s point…you are definitely in another ballpark. No clue what you’re talking about.
We agree that you have no idea what I am talking about!
David P says:
Thursday, July 21, 2011 at 10:40pm
“Divine Consensus”? You know how to search Feser’s blog.
When I said “No clue what you’re talking about,” you were the referent.
Can science study the number 4? How about the pain I felt yesterday when I stubbed my toe on the fridge. Can science study what it felt like to me at that moment?
Can science study why properly formed arguments always produce true conclusions when the premises are true?
No.
Beetle says:
Friday, July 22, 2011 at 11:40am
I hear you refusing to admit that Feser is silent on Divine Consensus. Why is that so hard for you?
Feel free to demonstrate that you understand Coyne’s point, and why a skeptic might argue that your response illustrates his point. I don’t expect you to agree, but understanding an oppositional view has its own value.
Yes, science and mathematics can address the three scenarios you offer.
Here’s the cartoon DavidStarling and I both liked: http://www.calamitiesofnature.com/archive/?c=547
David P says:
Friday, July 22, 2011 at 1:48pm
The term is “divine concurrence.” Remember, you can always Google if you want to find what Feser has blogged on the subject. Some other terms that might pop up similar results: determinism, free will, divine causation.
For an Aristotelian-Thomist like Ed Feser, the view is that God is the “unmoved mover” that ultimately initiated and that continues to sustain every event. You can check out his book, The Last Superstition, where he covers this in detail.
Coyne says:
“what conceivable observation about the universe could convince you that God does not exist?”
What he is hinting at is the idea of falsifiability. If a theory is unfalsifiable, then there is no evidence whatsoever that could prove it wrong. It is compatible with any set of evidence.
Consider the man who believes that everyone on the subway is secretly plotting to kill him. No matter how many times we try to explain to him that these are just normal subway riders with no interest in him at all…he will say, “ahh but that is exactly what we would expect if they were plotting to kill me!”
So the man’s thesis about the subway riders is unfalsifiable. Even if a subway rider said, “dude, I’m not trying to kill you, I promise,” he would still respond the same way.
Coyne argues that theism is like the man on the subway. There is no empirical data that could prove God does not exist. So supposedly it follows from this that belief in God is silly.
Another way to look at his argument is by way of predictive power. A scientific theory is good if it makes solid predictions about reality that can be checked. So if a theory doesn’t make any predictions that distinguish it from other theories…then how can it be verified?
So he is arguing that theism cannot be verified in the same way that good scientific theories can, and thus it is silly to believe.
“Yes, science and mathematics can address the three scenarios you offer.”
I would like to hear your explanation of how science and mathematics three three of those.
Robert says:
Friday, July 22, 2011 at 6:28pm
Yea, as a matter of probability theory, the man can’t have it both ways.
If he claims that the appearance of “normal subway riders” is evidence for a murder plot, he must conversely think that the appearance of “hostile (or non-normal) subway riders” argues against a murder plot.
If the Salem witch hunters said “a good and proper life” was evidence that a woman is a witch, then then they should have also said that an “evil and improper life” is evidence she is not a witch!
If Randal argues that God’s hiddenness, to test our faith, is actually evidence of God’s existence, then Randal should also say that the miracles described in the Bible argue against God’s existence. (I’m not implying that Randal argues that premise, but others certainly do.)
If evidence E is counted to support hypothesis P(H), the lack of that evidence ~E must be counted against hypothesis P(H). Otherwise, the math just doesn’t work.
David P says:
Friday, July 22, 2011 at 7:19pm
Robert,
If x is evidence for y, it does *not* follow that not-x is evidence against y.
The subway riders are evidence for “normal subway riders” and also “patient, murder plotting subway riders.”
And it is ridiculous that you are trying to make out “patient, murder plotting subway riders” into the “non-normal” category to make your (bad) math work.
Consider this:
Smoke is evidence for fire.
Embers flying through the air is evidence for fire.
Would you accept my argument that since embers flying through the air is “non-smoke” that we must therefore accept that they are evidence against there being a fire?
That’s absurd.
Robert says:
Friday, July 22, 2011 at 7:52pm
I think the math is just fine. I’m taking this from people much better at probability theory than I am:
P(H) = P(H)
P(H) = P(H,E) + P(H,~E)
P(H) = P(H|E)*P(E) + P(H|~E)*P(~E)
That’s true, but I am talking about expectations and probabilities. When calculating the probability of P(H), E and ~E have to balance out. Otherwise, your expectations will on average turn out to be wrong.
Maybe they are, but the two degrees of evidence are 50-50, 30-70, 10-90, whatever. They have to balance out. If “normal subway riders” is extremely strong evidence of P(H), then finding the opposite would not also be extremely strong evidence of P(H). Otherwise there would be no sense at all for treating either case as evidence.
If finding E and finding ~E give us the same confidence in P(H), then we should not waste our time testing; we should certainly not look at a test result and say “Look she REALLY IS a witch!” if we were going to have that conclusion no matter what.
David P says:
Friday, July 22, 2011 at 8:32pm
My major required some heavy duty probability classes. Check it out:
His theory is correct:
P(H) = P(H,E) + P(H,~E)
His theory is not correct:
P(~H) = P(~H,E) + P(~H,~E)
It is important to note that E is “people on the subway”…it is *NOT* “normal people on the subway.” If it were, then the man would have a circular theory…since obviously “normal people on the subway” entails (makes 100% certain) that the man is incorrect. E is simply the observed people on the subway.
P(H) = P(H|E)*P(E) + P(H|~
E)*P(~E)
The whole point of the crazy guy subway thing is that P(H/E)=P(~H/E).
In other words, the evidence doesn’t contribute any probabilistic weight towards his theory or its negation.
Nice try though.