UKC

I believe in logic - I think it is reliable. Two mutually contradictory statements cannot both be true.

Are humans fully rational?

Does evolution require us to have full rationality and if it didn't, how would we know?

Imagine a fully rational being knows what is true via a traffic light system. They see green they know it is true, they see amber, they are not sure and if they see red they believe something is not true.

Now imagine a being who only sees amber and green. They are not fully rational and fail to see that some things they believe are not true. They may skirt by the issues and avoid things they are not sure of, concentrate on green lights and get by pretty successfully but at the end of the day they may have blind spots where their logic is not reliable.

If evolution could successfully progress with beings whose perception of logic was akin to the second case, how would we know? Can we be sure that the logic we have to the degree that is necessary to function is fully reliable?

This dilemma is one of the reasons I hope there is a God, otherwise I cannot trust logic.

btw I do believe in evolution.

In reply to Nigel Modern:

The town I live in has one set of traffic lights. One two separate occasions the missus has driven up to the lights when they were red, then as she reached them they changed to green and she stopped. I always said she was illogical, now I have your post to back me up.

In reply to aln:

...and there was me trying to be serious :O)

In reply to Nigel Modern:
I recommend looking up and reading about Type 1 and Type 2 reasoning. Human's don't often rely on pure logic to guide behaviour, preferring for the most part to trust a fast, heuristic process that gives reasonable answers a lot of the time rather than a much slower process that has more chance of giving more logically correct answers.

-edited typo

In reply to john arran:
Yes, I understand that John...I suppose that is my point. But it does undermine our assertions that we can/are progressing towards understanding the universe. Claims made very commonly nowadays.

I suppose my question is, 'Can we do pure logic? If we can't how would we know?'

In reply to Nigel Modern:


Surely they can both be valid in terms of the logic used to arrive at them?

In reply to Ridge:

I think the definition I used is commonly used as a statement that our thinking is, at its best, or at least potentially, 'true' in some absolute sense. I may be wrong.

In that context the situation you refer to implies a deeper context which explains the apparent contradiction of the 2 statements.

In reply to Nigel Modern:

Just because we don't rely on logic most of the time doesn't mean we can't reliably use logic when we feel it's important to do so. We don't determine how the universe works by gut feeling.

In reply to Nigel Modern:

Does evolution require us to have full rationality and if it didn't, how would we know?

Evolution does not require rationality. It does not require brains. It does not require cells.

For the rest of your post, I know that I am not a super intelligent wonder being. I don't have to be a super intelligent wonder being to know that.

In reply to Nigel Modern:


obviously we're not fully rational because we know people do irrational things.


obviously it doesn't require us to because we've evolved to be not fully rational. we know this



this doesn't seem a very useful analogy and it's a bit confused. either in both cases the people can be wrong. or in the second case they see what the fully rational see as red as amber.

In reply to lowersharpnose:

I'm kind of hoping that evolutionary theory has addressed whether, since we are a product of its processes and that consciousness and logic occurred because they were necessary to survive, how we can be sure that there aren't currently and always will be areas where we sailed right through amber, past the red light we couldn't see.

Or to put it another way...are deluded ie believe things which are false.

In reply to Donnie:
I think you are applying absolutes in right/wrong when actually amber is a state of awareness within an organism which might imply right/wrong but is not right/wrong in and of itself.

Actually, I do think the analogy needs refining tho'...and I'm not sure what you have done

In reply to Donnie:

I'm interested that you assume that evolution hasn't produced (and I think I should be very clear here) the potential for full rationality ie we are not fully rational at all times...I guess we all agree on that.

That's a pretty major statement...and one that I think I agree with. I can't see how evolution needs fully rational beings. It is an 'accident' of that process.

If evolution has not produced the potential for full rationality...potentially there will be things we miss, even following the utmost diligence...and there's nothing we do about it. In fact natural selection might depend on what could be pretty radical delusion for the species survival ie all the fully rational species in this or other universes died out...possibly because they spent too much time debating rationality and forgot to reproduce.

In reply to Nigel Modern:

Let me give you an analogy.

You go to the supermarket and see one widget for £3.28 but next to it you see a pack of 7 widgets on offer for only £29.99.
If you need 7 widgets you may fall for the scam and buy the multipack, or alternatively you may notice the anomaly and buy 7 individual ones. What you almost certainly won't do is to calculate the exact cost of 7 individual widgets, as it isn't necessary to do so to arrive at a good decision in this case.

Logic is a bit like arithmetic in the analogy: it's there if we need it but most of the time it's too time-consuming so we don't bother. This tends to mean we occasionally don't bother when really we should, in which case we buy the multipack. None of this says anything about whether we have logical capabilities or the extent of those, but it does explain why it's misleading to assess our species' logical ability by observing everyday illogical behaviour.

Having said that, I'm sure there are many people who wouldn't know a logical construct if they were slapped in the face with it.

In reply to Nigel Modern:

All evolution depends on is genes.

It does not depend on deluding bacteria.

You seem to have the idea of intent or purpose behind your evolutionary ponderings.

In reply to john arran:
I agree fully John. Assuming I fully understand your reasoning...what I'm questioning is whether on our best day with the wind behind us, in the final analysis can the best of us, potentially come to understand the universe (as some are claiming we are close to) and then be sure? There seems to be an underlying asumption/aspiration(?) that, as a species, we are capable. An aspiration I can cope with...an unacknowledged assumption is another thing.

I consider life to be an acceptable delusion...which comes into your constructs, I think.

In reply to lowersharpnose:
I agree, I'm asking another question ie is the rationality which evolution has given us to be fully trusted? I believe it at least needs to be interrogated.

In reply to Nigel Modern:



I'm just saying it isn't clear what you're analogy is saying.

In reply to Nigel Modern:

You didn't say "potential" but I don't think human's are potentially fully rational.

Yes, irrationality could be good for species survival.

Obviously there are "things we miss"

This seems a bit of nonsense debate... we're not fully rational. and that's that.

Merry Christmas!!

In reply to Nigel Modern:



Really? Who's claiming that? Or assuming that? Almost by definition no serious scientist is. Unknown unkowns etc.

In reply to Donnie:
'We will one day explain everything' is a commonly expressed belief amongst people promoting what they call a scientific perspective and often as a reason not to believe in God. I can think of friends, colleagues and interestingly Richard Dawkins expressing this view. It is widespread.

In reply to Nigel Modern:
Some people argue that the universe is in fact flat, where in truth this is incorrect as we have mountains.

In reply to Skol:

True...though I've never heard Richard Dawkins referred to as akin to a flat-earther.

I think the questions I'm asking must have been posed by materialist philosphers, so I guess that is the way to go.

In reply to Nigel Modern:


It's a good question, and the answer is, no, we should not fully trust our intuition and innate rationality. It is pretty good, but not perfect. We can see that it's not perfect owing to, for example, the placebo effect and the need for double-blind medical trials.

A more simple demonstration is this one, which fools us: http://en.wikipedia.org/wiki/Checker_shadow_illusion

In that illusion, the brain is making some assumptions about how the world is, and that fools us.

Indeed, that tells us why our rationality is imperfect, it is programmed by evolution and will do a pretty good job in the sort of situations we've met over evolutionary time that had survival consequences. So, for example, anyone under the impression that snakes are nice, cuddly toys would not leave as many descendants.

There are a huge list of human biases (e.g. http://en.wikipedia.org/wiki/List_of_cognitive_biases ). Thus, if we want to know how far we can trust our reasoning we have to know about our biases and know how to take them into account (double blind trials are an example of that).

In reply to Nigel Modern:


Any chance of a quote of Dawkins saying that?

In reply to Nigel Modern:

Logic is but one tool in our box that allows us to make sense of the world. I wouldn't rely on Logic alone but when combined with the Scientific method it's a formidable force.

In reply to higherclimbingwales:

True but I'm almost shocked at how easily current thinking has dropped the idea of humans aspiring to some ideal of logic...very post modern.

Coel...it was on youtube...I was almost gob-smacked. I'll look in my history. I chanced on it a few days ago.

In reply to Coel Hellier:

I have searched my iPad but nothing...could be on the other iPad or the desktop...I may find it. I'd hate to misquote him...he certainly was saying something along the lines that as more and more is explained he felt there was less and less space for God to be necessary but I can't recall if he actually said a disproof of God was possible by that route.

Also, it might not be his considered position...I was surprised at him saying it, which is why I remember it.

What do you think Coel...if science explained most or all of the processes of the universe, including how life formed and evolved. Is it a disproof of God? I don't think so and is based on a very man-centred view of God.

In reply to Nigel Modern:


Yes, I'd expect him to say that. It's fairly true that many of the reasons that people have traditionally put forward for why there is a God have since been shown to be not so.


It's not a disproof, it just leaves us with no good reasons for postulating a god.

That's not the same as being confident that one day we'll explain everything, but not being able to explain something is not in itself a good reason for postulating a god.

In reply to Coel Hellier:


Agreed and that's where theists often tend to run into problems. Arguments in favour of there being God for me are much more to do with the nature of man, what I perceive in myself and how I interpret the good and the bad I see there and in others (in as much as I can interpret this from externals)...and of course certain historical events which you and I probably don't want to get into :O)

One thing I would say, and this is not me having a go at atheists or atheism (it is a well thought through theoretical position I respect but just disagree with), is that much of what RD and other atheists say about the Bible and theology doesn't get near posing the real questions I have about faith. Sometimes real questions are raised and they remain the classic ones of suffering etc. And I've yet to hear of an atheist really asking questions like 'I suppose of God exists then He/She/they are outside of emergent things like time and space, so what would such a God look like to us..and how might such a God communicate with us if separation was a reality, whether it always was the case or simply emerged?' It makes me think they have never really considered the possibility of the existence of God and therefore sought to work through the issues, at least not in the light of what we now know (or think we know) about the universe we live in.

Have you ever really considered the possibility of there being a God and if so what might the God you have considered look or feel like?

You don't have to answer...However I am slightly curious.

In reply to Nigel Modern: speaking as a non-militant atheist the reason I dont think about such complicated things is that I simply don't believe in God and thus don't to use rather stretched logical constructs to try to prove/disprove gods existence.

Why were you surprised by Dawkins saying that the growth of knowledge leaves less space for God? Think about a world where you need to explain the sun, moon, tides, disease and so on. I don't espexially like Dawkins but this seems uncontroversial

In reply to Nigel Modern:


That's kind of an interesting question, but surely a rational atheist swiftly arrives at 'no', because there is no point at which, or evidence for which, one might start, based on 'what we now know (or think we know) about the universe we live in'

In reply to Nigel Modern:
This is too philosophical for me therefore, I'm oot.

In reply to Nigel Modern:


Atheists are familiar with this style of apophatic theology, were the tactic is to argue that God could exist in such a way that there would be no evidence for God. The reason for this is thus to explain away the lack of evidence for God and lack of good reasons for supposing that there is such a God.

The atheists tend to shrug and say that they'll take an interest if and when good reasons are forthcoming for supposing that such apophatic theology claims are true. (Though of course that could only happen if it was first sorted out what the claims of apophatic theology actually are.)

In reply to Coel Hellier:

From what he says and has written Dawkins is right to reject the God he doesn't believe in - I would.

As far as apophatic theology goes...that is not what I was saying. There would be evidence but possibly of unexpected kinds and of course there is the historical evidence which you either accept or reject. As far as evidence of other types an analogy would be 2 dimensional beings interacting with a 3 dimensional one. They would be confused by the 3rd dimension etc You're probably already with it.

Dawkins talking about science eventually explaining everything and leaving no room for God...I'm still surprised. There is no challenge to faith in that...the more we find out, the more I go 'nice one Big G', like a coin with 2 sides but which side you look at depends on prior belief.

Anyway I'll sign off now as disinterest is what I'm hearing.

In reply to Nigel Modern:

I don't understand this or bouldering. Is that logical?

In reply to Nigel Modern:


That sort of reply is a rhetorical device to suggest that Dawkins conceives of God only one way, but really Dawkins (and most atheists) are aware of the range of different conceptions of God.


If you ask believers around the world and across history what reasons they have for God, the idea that one needs a God to explain X, Y and Z is common, and thus rebutting that is fair and legitimate. Of course it's also fair that sophisticated believers don't envisage God that way, but in many ways that's a newer development arising out of the fact that X, Y and Z can be well explained without any gods.

In reply to Nigel Modern:

We can obviously do logic within the constraints we ourselves apply to logic. Therefore we can define something as "true" or "false" ONLY by our own definitions of what constitutes "true" or "false" (or "unsure" for that matter). Whether these constraints are universal truths, who can say ?

In reply to Coel Hellier:

As are most religious people of course, and they too don't believe in most of the different kinds of god they could imagine.

In reply to Nigel Modern:

What does this mean? I think we're rational in the sense that we make decisions that are logical, but we don't all have the same goals or opinions as to what's true or not (we don't really know what these are!). Religion's not really the issue - it's just an example where some believe that something's true (and so it informs their decision) and others don't (so they see the religious as irrational).


Still depends what you mean by "full rationality". We make best guess decisions based on logic I'd say, we make a picture of the world and then readjust based on experience - following the "assumption" (if that's the right word) that what works once will work again.


Why?

In reply to Nigel Modern:

What are you going to interrogate it with?

What does "fully trusted" mean - do we have perfect knowledge and so the ability to make exactly the right decisions? No. We don't even know what our goals are really...

In reply to Nigel Modern:

I think you are misunderstanding what logic is. Logic is a formalized tool for reasoning and deduction that we have constructed to help us solve problems and prove things, often mathematically. (see mathematical logic and proofs).

Logic can be used by machines and computers, it's not something we have in our brains as such but merely a set of rules for defining truth that our intelligence is capable building.

For example, You have an object and you wish to identify it, you wish to know if it is a black ball or not. You define a black ball as something that is black and is spherical.

So you apply a some logic to solve the problem. You ask 'Is the colour of the object Black?)

Yes = move to question 2

No = It is not a black ball

Then you ask 'Is the black object spherical?'

Yes = It is a black ball

No = It is not a black ball

That is an example of logic, someone who has never before known of logic or has any idea what a black balls properties would be (such a computer) can now tell if anything is a black ball within it's defined parameters. Someone with a red ball or a black cube wold easily work it out using the system, whether they evolved it or not.

There is not some higher level of logic that we are to primitive to have come up with which could mean something that is black and spherical could turn out not to be a black ball within the definition we have set.

What baffles me about your OP is what any of this has to do with their being a God?

In reply to Lord_ash2000:


It's a standard argument for God: "If there is no God, then there would be no reason to suggest that human logic and reasoning has any reliability or validity, therefore atheists using reason to argue against God is self-defeating and irrational; theists think that our rationality is a gift of God, so we don't have this problem".

The answer is simply that, since humans are the product of evolution, we would expect our brains to be pretty good at dealing with the world and thus to run along the same logic as the world runs on, afterall, brains evolved precisely to deal with the world.

In other words, it is classic case where advances in science (understanding our origin through evolution) refutes one of the arguments for God. In other words, it is exactly as the Dawkins quote up-thread, which Nigel expressed surprise at.

In reply to Lord_ash2000:
That is not even an example of strict logic. There is no definition of sphericalness for a physical object. Let's say that we have a billiard ball - is that spherical? What about the Earth - is it spherical?
Probably you'd say that billiard ball is spherical, but the Earth is not (due to curvature effects and the protrusion of mountains and inclusion of valleys). Well actually the Earth is smoother (proportionally) than the billiard ball: http://www.curiouser.co.uk/facts/smooth_earth.htm

There are different types of logic. There is common parlance logic - e.g. logically speaking, it's better to buy a multipack once a month if it's cheaper, lasts long enough and storage space is plentiful than to buy a single each week.
There is philosophical logic or reasoning - which due to the fluffy and squishy nature of words, is quite able to produce contradictions. It's useful, but not infaillible.
There is mathematical logic, which is pretty much true. Mathematics is never wrong really - however the _interpretation and application of mathematics to the real world_ can and is often wrong. For example Newtonian physics is correct, it just so happens it's not an accurate enough model for every scenario. (Correct being defined as consistent, but not complete (which is impossible - see Godel's theorem)). Mathematics as a field strives to deliver consistency, but not completeness. There have been occasions where inconsistencies were almost introduced to Mathematics canon (
Russell's paradox), but it's believed these can be weeded out.

As a side note, there is not one "mathematics". There are infinite, and then there is the mathematics of mathematics (conveniently bundled into the term mathematics). There is the mathematics of mathematics of mathematics, ad infinitum. All bundled under mathematics. We pick and choose of this 'mathematics structure' a few systems that accurately model our world to use for our benefit - whether or not it's useful does not affect it's "truthfulness" (consistency).

In reply to Nigel Modern:


i'd have thought that evolution doesn't "require" anything from us. it's a discription, not a "being"

this is where i find many people who believe in god(s) fail in their arguements. they treat evolution as an alternative faith like their's, but it's not. to me it's more of a frame work, a guide, a description.

using (for example the christian) god to discribe how the universe works makes god "a god of the gaps" or "a god of ignorance". ie... "i haven't been able to work it out so god must have done it."

are you really saying that a book written 3000 years ago (the old testament) knows more about the universe than what the science of the last few hundred years has taught us? now that's not logical.

In reply to Nigel Modern:


really? I hadn't come across that view. Do you have a link to Dawkins?

In reply to Nigel Modern:
I just had a quick google. I didn't find Dawkin's views - just references to them that weren't that clear.

I did find an interesting quote is from Einstein, which perhaps sheds some light on what's going on here. A difference between what is in theory possible with science, and what's possible in practice for humans using science. A further distinction would be what's likely to actually happen.

To paraphrase Einstein: everything could be described by science but it may not make much sense. For example, science can describe a Motzart symphony as a sound wave but that's of limited use.

A couple of points here.

The first minor. Science could also describe the effect of Motzart on humans. Ie in terms of how and why it makes humans feel what it does.

The second point is more general and more relevant to this conversation. Saying that everything is in theory describable by science isn't the same as saying that in practice, it's possible for humans to be capable of doing so or, even ifit might be possible, that it's likely that they will.

In reply to Nigel Modern:

I don't think either that humans are particularly rational or that it is necessary for evolution to make us so. There are a few reasons, but they all boil down to the fact that evolution is not intelligent design.

Evolution is backward looking and brains are expensive so there is a tradeoff. We aren't necessarily as smart as we need to be in the present, but just smart enough for our ancestors to survive the past. A capability for abstract reasoning and logic has not been a particularly relevant life skill for many of the population until recently.

Following chains of logic takes time and brainpower. If you have a shortcut that gets you to the right answer efficiently 99% of the time then it is more efficient to just use that instead.

I see humans as being fundamentally irrational and superstitious but capable of using logic if we really concentrate.

I think Peter Watts summed up the evolution of superstition better than I ever could:

"fifty thousand years ago there were these three guys spread out across the plain, and they each heard something rustling in the grass. The first one thought it was a tiger, and he ran like hell, and it was a tiger but the guy got away. The second one thought it was a tiger, and he ran like hell, but it was only the wind and his friends all laughed at him for being such a chickenshit. But the third guy, he thought it was only the wind, so he shrugged it off and a tiger had him for dinner. And the same thing happened a million times across ten thousand generations

and after a while everyone was seeing tigers in the grass even when there weren't any tigers, because even chickenshits have more kids than corpses do. And from those humble beginnings we learned to see faces in the clouds and portents in the stars, to see agency in randomness, because natural selection favors the paranoid. Even now, we are wired to believe that unseen things are watching us."