It isn’t easy to determine what claims should be believed and what claims shouldn’t be. There is no easy answer to the question “when should we believe”. However, this is a very important discussion to have. It may not always be obvious whether we should believe something or not, but it is possible to determine whether or not a belief is rational.
But, before I discuss how we can determine whether a belief is rational, I should discuss when it is necessary to determine if a claim should be believed. This is a difficult concept for a lot of people. Many people want to be overly skeptical, and others aren’t skeptical enough. So when should we determine if our beliefs are rational? When our beliefs have a significant impact on us or on those around us. But what does that mean? It means that everyday claims don’t tend to count. If I were to say “I want cereal for breakfast,” Withteeth does not have to be skeptical of that claim. He doesn’t have to demand that I prove that I want cereal. If I were to say that I have class at 4:30, Withteeth still does not have to be skeptical. However, if I were a drug addict who had a habit of using the “I have class” excuse to sneak out and get high, then he has reason to be skeptical. He can demand that I show him my class schedule, and he can even follow me to class, watch me enter the classroom, and ensure that I don’t leave the entire time. In short, he can know for sure that I went to class, and he can base his belief on that knowledge. But he shouldn’t believe that I have class at 4:30 without at least looking at my schedule if I am known to be untrustworthy. But, while this example has a significant impact on our lives, it doesn’t effect anyone else. There are other things that have a lot more impact and, as such, require a lot more evidence. Belief in God is one example of such a claim. If God exists, then his existence, assuming the Bible is an accurate representation of God’s personality, has a significant impact on the world as a whole. As such, existence of God requires more evidence than whether or not I am skipping class. Showing that God exists is a start. This can be done in a number of ways. The easiest would be to point to God and say “there he is” and for God to then do something that proves he is God. Without that, though, you can also prove God exists by showing that something could not exist without God. This is the route that a lot of theologians take. The problem is that it is difficult to prove that something could not exist without God. But, even if God were proven, that is just a start. You would still have to prove that this God, again assuming the Bible is accurate, is the God of the Bible and not some other God. As you can see, this is a tall order.
So how do we know that our beliefs are rational? By determining whether they are probable. Absolute knowledge isn’t necessary to say that a belief is justified (it isn’t even necessary to say that you know something). But there is a degree to which you can say that a belief is rational. Evidence is how we determine the probability of a belief being true. Going back to the skipping class example, how would Withteeth know that it is rational to doubt my claim that I have class at 4:30? If he has caught me skipping class a number of times before, then it is likely that I would do again. If it is the middle of the semester and I have never gone to a 4:30 class before, then it is likely that I am lying. If he has heard from a number of other people that I constantly skip that class, then he has reason to believe that I am lying. He is not rational in believing that I will skip my class, or that I don’t have class, if I have only skipped one class that he knows of. He is not rational in believing that I don’t have a class if I am always at school from 9am to 6pm and he doesn’t know when each class is. And he is not rational in believing that I’m lying if one person told him that I skip the class a lot. He doesn’t have enough evidence to make that claim. So how would he determine the probability that I will skip class? He would need to do some research. He could go to my professors and ask them, but they may or may not know. He’d also have to go to my classmates. Assuming that a number of them know who I am and remember my relative class attendance, he could create an average of how often I probably attend class. From there he can create a probability of my likelihood of my skipping class. Though his evidence would be much stronger if he had a more concrete evidence. For example, if I had a camera watching me while I sat in class during every class I attended, then he could say for a fact how many classes I skipped. Then his probability would be more accurate.
But how high does the probability have to be for the belief to be justified? That depends on the claim. If the probability is 51%, that should be enough for the claim “I have class at 4:30.” But a claim like “God exists” requires a higher probability.
So when is it rational to believe a claim? That depends on the claim. It is always rational to believe the claim “I want cereal for breakfast,” but, depending on certain characteristics related to the person making the claim, it might be irrational to believe the claim “I have class at 4:30.” However, in most cases. It is perfectly rational to believe that claim as well. But it is less rational to believe the claim “God exists” because of the lack of evidence and the low probability. I’ll link to a few sites that may help with further understanding of this concept.
http://plato.stanford.edu/entries/epistemology-bayesian/
Click to access Reasons-for-belief.pdf
http://www.quora.com/Is-belief-a-rational-default-position-for-any-claim
hessianwithteeth 
January 21st, 2015 at 3:37 pm
Meyer Pincus reply to Hessian withteeth
“FACTS” | “TRUTH” — What are they?
A preponderance of visable material evidence, compiled at any time, to; with use of logical deduction critical thinking, and (“expert at the time” consensus) determine validity ,of any claim.
1) Visible Material Evidence
Witnessed observation, collected and recorded data
a) Compiled at a Point in Time ( when the meansfor collection and recording were rapidly being improved in capability and precision – casting doubt on all previously determined validity)
If this being the case; Logicical thinking informs one, all facts and truth are “time dependent”, changeable, not absolute.
[ mp ]
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January 21st, 2015 at 3:49 am
From what I can gather from the links that you provided, there is considerable dispute amongst philosophers about what constitutes a rational belief. Whilst most may subscribe to your basic premise that ‘evidence is how we determine the probability of a belief being true’, there is still considerable dispute as to what kind of evidence ‘counts’. These things are not self-evident. We don’t all agree. Therefore, it is not correct to say that ‘it is less rational to believe the claim “God exists” because of the lack of evidence and the low probability.’ This is your view. But it is not self evident. It is disputed. Therefore, I would say it is as rational to believe the claim that ‘God exists’ as it is not to believe it.
Also…
‘You would still have to prove that this God, again assuming the Bible is accurate, is the God of the Bible and not some other God.’
Firstly, the ability to ‘prove’ a belief isn’t necessarily a marker of how rational a belief is (see above). It might be perfectly rational for that person, in that place and time, to believe something, even if you feel you have good reasons not to.
Secondly, there are plenty of theists who would say that the Bible provides evidence for the existence of God, yet don’t accept everything the Bible says about said God as being true. Similarly, some don’t see the different religions in terms of different gods so much as in terms of different facets of the same god. Therefore, to try and lump all theists (or even all Christians) together as needing to prove what you think they need to prove is no fairer than Christians telling you what they think you need to prove.
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January 22nd, 2015 at 12:45 am
The difference between Epidemiologists is a difference of degrees. Some believe that it is impossible to know anything. Some believe it is possible to have knowledge using probability, but you can never know 100%. Still others believe that you either know or you don’t and probability is irrelevant. I fall under the second category (though I’m not an Epistemological).
My saying that it is less rational to believe in God is because “I have class at 4:30” is a very basic claim. I’m not saying something controversial, nor a I saying something unlikely, when I say that I have class at 4:30. However “God exists” is a controversial claim, and it is not obvious that a god exists.
Proof isn’t dependent on others agreeing. Nor do you have to be completely certain to prove something. It is, like evidence, a matter of degrees. If you are believing something without evidence, and thus believing something that you can’t prove (to any degree), then you are, in fact, being irrational. Evidence also isn’t dependent on the person saying “this is evidence.” We may have grey areas where evidence is concerned, but we do have standards.
How is it not fair to say “all religions require a certain degree of evidence before they can say their god(s) is proven”? I’m not saying all religions are the same, nor am I saying all religions must provide the same evidence. I’m merely saying that evidence is required and degrees of probability matter.
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January 22nd, 2015 at 10:54 am
Whilst I agree with most of your points, I still don’t agree with your statement that ‘it is less rational to believe the claim “God exists” because of the lack of evidence and the low probability.’ It’s the ‘lack of evidence and low probabability’ bit that I think is a matter of opinion and therefore controversial.
I accept that you think there is a ‘lack of evidence and low probability’ that God exists. However, I strongly disagree with that – and (according to your links) so do plenty of others. I believe in God because I feel I have enough evidence to think that the probability of God’s existence is quite high. If I didn’t, I wouldn’t believe it. However, I also accept that a fair portion of said evidence has not been verified in any material sense. Hence it would be dismissed by many people in much the same way (in my view) as a blind person might respond to the belief statement ‘the grass is green’. It’s just completely outside their understanding and experience.
You yourself say that ‘God exists’ is a controversial statement. If that’s the case, then I think it’s perfectly reasonable for me to say that ‘there is a low probability that God exists’ is also a controversial statement. (And yes I have read ‘The God Delusion’). It’s controversial because not everyone agrees with it.
‘How is it not fair to say “all religions require a certain degree of evidence before they can say their god(s) is proven”?’
I didn’t say it wasn’t. And I still haven’t. I said that the following statement wasn’t fair: ‘You would still have to prove that this God, again assuming the Bible is accurate, is the God of the Bible and not some other God.’ As I explained, this is not fair because it *assumes* that the theist believes their god to be different from the gods of other religions. If they do, fair enough. But if they don’t, they shouldn’t be expected to prove it.
(This last isn’t something I would have picked you up on, except that you seem very quick to point out that religious people shouldn’t make assumptions about atheists. I’m thinking that should work both ways.)
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January 22nd, 2015 at 12:18 pm
Why do you assume I’d refer you to Dawkins? Richard Carrier actually deals directly with probability where god is concerned, Dawkins doesn’t.
The fact that what you call evidence can’t be verified is the reason that I say there is a lack of evidence. Evidence can necessarily be verified. Most often it is either “I had an experience” or “the bible says” that is used as evidence. That is not the same as a blind person who has never seen the grass before. In the case of the blind person, they realise that their eyes are the problem. That is not the same as saying “I have evidence” and someone else saying “no you don’t.”
Anyway, you’re ignoring the context. My comment is in relation to the claim “I have class at 4:30.” Do you believe that both “God exists” and “I have class at 4:30” are equally controversial and require the same degree of evidence, thus making it equally rational to believe both?
t
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January 22nd, 2015 at 4:21 pm
OK. Imagine for a moment that the majority of people were blind and it was only a few that were making the truth claim about the grass being green. In that situation, it would be unlikely that the blind person would know there was something different about them. Since they couldn’t see light or its effects, they would assume that the ‘problem’ lay with those who claimed that they could see. Also, since they couldn’t see light, they wouldn’t immediately think of investigating to find out its nature. Or they might try to investigate it in ways that made no sense to the people who were claiming that the grass was green, leading to a negative result and perhaps even bolder claims that ‘the problem’ lay with those making the claim.
Now I would say that at least some of my evidence for the existence of God is a bit like that. God as an explanation for my experience seems perfectly rational to me. It makes sense of the evidence. But that does not mean that my claim will be accepted by others. As I have said, my experience cannot be objectively verified – in part because some of the investigations that would be required to substantiate it haven’t taken place. More recently, there have been some investigations that point to the probability that there is more to our world than science has yet documented, but solid evidence remains sparse, partly because psychic experiences are largely dismissed as (at best) fantasy or (at worst) deception, partly because many of those who have them soon learn not to talk about them and partly because such experiences are often not under conscious control (so it’s difficult to produce controlled experimental conditions to test them). But that doesn’t mean that it’s irrational for those who experience them to believe in them any more than it is irrational for sighted people to believe they can see or for gay people to believe that they are gay.
To conclude: I don’t think that “I have class at 4.30” and “God exists” are equally controversial since, as you rightly say, most people aren’t going to dispute with you over the timing of your class. However, I do think it is equally rational for *me* to believe both. In fact, *right now*, I think it is more rational for me to believe “God exists” because I think I have more evidence for that than I do for your class being at 4.30. All I have for the latter is your word for it… and no way of even seeking to verify the claim since I’m half a world away and don’t even know your real name! But this would not be the case for with teeth, so it might indeed be more rational for him to believe that you have a class at 4.30. And that was my point. What one perceives as ‘more rational’ might be perceived very differently by someone else.
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January 22nd, 2015 at 5:24 pm
PS: Looking at your links again, I guess my view comes closest to that of the Reformed Epistemologists in as much as I think it’s perfectly possible to come to a reasoned belief without material evidence. Also, to be honest, I don’t think controversy over a given belief has much to do with how rational it is. I’d say controversy is much more indicative of a fight for power. That’s been true of religion, politics, sexuality, medicine and even the hypothetical drug addict who claimed to have a class at 4.30 😉 But perhaps that’s a subject for another day…
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January 20th, 2015 at 2:13 pm
How does an Atheist define morality?
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January 20th, 2015 at 5:49 pm
How does this relate to the topic? Besides we’ve answered this else where I suggest using the search function.
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January 20th, 2015 at 1:58 pm
Does there have to be human observation in order to accept a claim?
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January 20th, 2015 at 3:40 am
I would have thought our current legal system(s) owed just as much to ancient (pre-Christian) Roman law, and indeed Germanic tribal law, as integrated into English law. There’s a bit of canon law in there too, but it surprised me when I started looking at some specific examples (marriage law being one) how much our current laws in fact reflected pre-Christian norms.
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January 20th, 2015 at 2:05 pm
In what ways have the current laws descended down from Pre-Christian norms?
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January 20th, 2015 at 6:04 pm
Just off the top of my head, and answering using the example of marriage law, which is the one I did a fair bit of reading on.
It was Roman law which established monogamy; more than one wife was not allowed in their system. It was also Roman law which required free consent from both spouses; the antecedent to the modern marriage vows. Germanic tribal law added to this the necessity for consummation; the idea that marriage can be annulled if sex never took place comes from Anglo-Saxon practice.
Marriage as a formal agreement didn’t move into the church until the late medieval period; before that it was generally done at home or in some other public place. Priests originally got involved as educated people who could act as witnesses. The idea of being married “before God” being a sacrament was a very late development.
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January 20th, 2015 at 6:06 pm
Interesting
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January 19th, 2015 at 10:29 pm
All of the principles of society including the rule of law are based on prophetic verses that refer to a belief in God. It works for ME, but I.could never preach about it. To be an Athiest is OK if you feel that it’s right for you.
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January 19th, 2015 at 11:59 pm
If our laws are derived from morals which, as you claim, are derived from “prophetic versus” ie: religious texts, then how come we disregard the violent, immoral and ridiculous claims that religious texts such as the Bible and the Qur’an make? The fact that we are able to pick and choose which passages we deem to be moral while disregarding the others (stoning adulterers to death, slavery, inferiority of women, murdering homosexuals, et cetera) implies that we derive our sense of morality from a source outside of these religious texts.
If you can pick and choose what you do and do not follow from a religious text then you cannot claim to derive your morals from these writings. They may contain some philosophical ideas which you apply to your day to day life, ideas which also exist in writings that make no claim to divinity. But whether you chose to apply these ideas or not does not come from the book itself.
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January 20th, 2015 at 1:51 am
Interpretation of a holy book teaches a clean and healthy, peaceful way of life. The Qu’ran and the Torah as well as the New Testament are faith based and teach a clean way living. The examples you selected in brackets are from recent times as well as ancient times. Aside from the freaks who choose to misinterpret religion, I can only conclude that they represent a cult percent of all societies.
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January 20th, 2015 at 12:54 am
“All of the principles of society including the rule of law are based on prophetic verses that refer to a belief in God.”
Oh really, and how do you know that? And which god?
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January 20th, 2015 at 1:38 am
There is only one God. That one.
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January 20th, 2015 at 1:02 pm
A bold claims, left standing without support. Alone and cold in the wind.
So Brahman then?
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February 10th, 2015 at 3:52 am
Is there more then one?
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January 20th, 2015 at 2:03 pm
I have to know which God as well. Different people have different reasons why they follow a God. The Quran, Torah, and the bible have different teachings even though people don’t think they do.
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February 10th, 2015 at 12:01 am
Is there more then one?
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January 19th, 2015 at 10:26 pm
If a human did not observe something, why should I believe it out of class textbook?
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January 20th, 2015 at 12:53 am
What? What do you mean by observe? Do you mean direct observation? Because in that case I hate to tell you, but direct observation alone is one of the most irregular and least trusted forms of evidence. Why becuase humans have spotty memories which change over time, and we will often think we saw something when we didn’t, or draw links where there are none.
Thought really your going to need to be more specific.
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January 20th, 2015 at 7:57 am
This isn’t about attacking a specific theory. I am not going to do that. It’s the way someone can describe something in a textbook that had no human observation yet when something a human did observe, the other human denies it. Why is it the something that has no human observation gets more credit that something that did?
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January 20th, 2015 at 12:42 pm
Your going to have to give examples because what your saying isn’t really something that normally happens in text books. Yes is there was not human observation then what ever we are dealing with is at least currently beyond the scope of human knowledge. Though they are many ways to observe something and draw conclusions from what you observe. We can also create many tools to help extend our senses so we can indirectly observe many more things.
By dancing around what you mean by observe is not going to help matters here.
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January 20th, 2015 at 12:52 pm
I see. I’ll have to think about this further.
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January 20th, 2015 at 1:11 pm
Perhaps I seem harsh, but I am ready discuss such topics, but if you are to have a meaningful conversation you first start by laying the definitions out for everyone to work with.
Because of that so long as you don’t define what you mean. I can’t make any meaningful progress to answering the question you posed, because I can’t know what you mean when talking about thing people have and haven’t onserved.
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January 20th, 2015 at 1:49 pm
I’m a student at a university. I took a geography class a while back. There was a claim made in the textbook for this class that Lake Agassiz existed between 10,000 and 15,000 years ago. From reading this textbook, I wasn’t fully convinced. Lake Agassiz supposedly existed according to scientists what is now Manitoba, Saskatchewan, western Ontario, North Dakota, South Dakota, and Minnesota. Currently the Red River flows north into Lake Winnipeg in Manitoba, Canada. The claim made by scientists is that what happened to previous Lake Agassiz is that it just evaporated. Really, just evaporated? During the last Ice Age, Lake Agassiz covered that land. As the ice retreated, we see what lakes and rivers are today. Today, there areas of wetlands in parts of Manitoba, Saskatchewan, Minnesota, and North Dakota. Your question up above is at what point is it rational to believe a claim? I have had doubts about Lake Agassiz for a while. I don’t want to be considered dumb or foolish. If this “Lake Agassiz” existed, what were the coastlines like during the increase and decrease in size during at which this existed? What were past coastlines of what is now known as Hudson bay? I have to ask questions to remove such doubt in order to believe a claim.
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January 20th, 2015 at 9:22 pm
Well first let me admit I’m no geologist, nor am I any kind of expert on Lake Agassiz but allow me to look at some of what your saying where critically.
“The claim made by scientists is that what happened to previous Lake Agassiz is that it just evaporated. Really, just evaporated?”
Well no looking on Wikipedia http://en.wikipedia.org/wiki/Lake_Agassiz it’s clear that the lake didn’t just evaporate. Over the course of it’s life the lake drained into other basins, and that water eventually got to the ocean, so while some of that water was lost over time, some of it flowed else where. So as the colossal glaciers which fed the lake dissipated the massive amount of melt water also was reduced over time, and also fluctuated some with the climate of the region. This whole process of change took thousands of years, and would have caused make geological changes which is probably the main reason we know the lake existed in the first place.
Also remember millions of years ago my home province of Alberta was a low depth sea, and you can find fossils of sea creature in many areas still, and that at one time all the earth landmass was packed together, so a giant ass lake taking up a big chunk of North America is really that ridiculous, particularly when you think that lake was made by a mile thick glacier which in turn covered most of Canada of thousands of years before the lake began to form.
Though again I’m no expert if you still not convinced (and really I don’t care if you are I have no investment into the existence of lake Agassiz) you should look around for some Lake Agassiz researchers and shoot them an e-mail.
Here’s a link to a paper reviewing some of the details around the Lake (pointing out flaws in previous methodologies and reviews) however there are shit tons of references at the bottom so if you really want to tackle the question that should get you started.
http://www.google.ca/url?sa=t&rct=j&q=&esrc=s&source=web&cd=12&ved=0CFEQFjAL&url=http%3A%2F%2Fwww.esci.umn.edu%2Fsites%2Fwww.esci.umn.edu%2Ffiles%2FREVIEW%2520OF%2520LAKE%2520AGASSIZ%2520HISTORY.pdf&ei=oRq_VOHRIYbisASDmYLYDg&usg=AFQjCNH_aABwIwItUmzIuuh3PguC6JWvaQ&sig2=MCijGh9s1HXvhTK9OLUjbg&bvm=bv.83829542,d.cWc&cad=rja
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January 20th, 2015 at 9:28 pm
Ok thank you for the information
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January 20th, 2015 at 1:56 pm
If someone a scientist provides me with such data such as Carbon Dioxide, Nitrogen Dioxide, and Oxygen levels between 10,000 and 15,500 years ago, that would be good as well. Did the Native Americans/First Nations…any such tribes observe the existence of this????
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