What is Circular Reasoning?

by God_Delusion 36 Replies latest watchtower beliefs

  • Mad Sweeney
    Mad Sweeney

    This is one of the greatest thread hijacks I've ever seen.

  • bohm

    Mad Sweeney: Sorry, but i do actually feel it is quite close to the point. With any position, it is a matter of somehow - using the rules of logic - tying that position together with truths both parties agree on; this being faith, observation or philosophical idea. Circular argumentation is, to me, that you tie the position to itself, so it become a kind of self-supporting chain of implications.

    Perry brought up a very interesting example where quotes in scientific litterature seemed like circular reasoning and i will give him full credit for this. I think he made a very valid point.

    The fundamental problem is how to go from "common ground" ( faith, observation or philosophical ideas) to 'proof' that something (evolution, the existence of God, 1914, ... ) is true. Circular is clearly not the right way. The dangerous thing is that to some extent everything looks like circular reasoning - Perry pointed out the geological column and evolution (carbon 14?) being adjusted to each other - but it touch all fields of science: How do we proove scientific theory A? We use theory B and C and some observations. How do we prove theory B? we used a slightly inferior version of theory A and C and some other observations, etc.

    I think this problem is an inherit difficulty, and why it is hard to find some definition of circular reasoning that can be used in context of eg. evolution.

    What i tried to do is to take a constructive standpoint because this problem of inferring what is true is something that mathematicans have worked upon, and a problem where you can say quantitative things (and why i philosophically think that predictions is the most important thing a scientific theory can do).

    I should properly have used a less polerizing example than evolution/creation though... It came up, and i couldnt resist taking the bait, though i am trying to attack it as a problem of false inference in this thread.

    UPDATE to my previous post. The Mitochondrial eve argument was written all to quickly and i can see it says something i didnt intend it to say. What i ment was that mitochondrial-eve style argument will show that if sexual life originated twice, independently, those populations contain genetic bottlenecks - mitochondrial eves - whose genes spread exponentially quickly over the entire population in that cluster. I believe the process that give rise to this exponential spreading is luck and perhaps some advancement genetically, and i think that in the end would make a system of two completely seperate, surviving, clusters of life of different origin unstable.

    As an example of this, most phylas has died out on earth. i dont think it takes much imagination to imagine this would also eventually happend to one of the two "clusters" of different life.

  • Mad Dawg
    Mad Dawg

    Your probability statements have no bearing on whether or not X is true - only whether or not you can accept it as true. Our understanding of germ theory had no bearing on the validity of spontaneous generation. As your equation is based on your assumptions, all that is needed to change the outcome is to say "I am not so sure" about one of the statements. Your equation is the epitome of circular reasoning: I have faith in evolution. Hey look! My equation proves me right! I can write the same equation with a revision of the premises and swapping out the variables. Viola! Creation probably happened.

    Science is what it is, we can't redefine it to include our pet theory.

  • bohm

    Mad Dawg: Now you are not adressing my argument at all, rather making some poor red herrings. If all that is needed is to change some assumptions - then please show me what you suggest. Show me how you believe the evolutionist and creationist will argue to arrive at P(O|E) and P(O|C). My figures was 1 and 1/2. Be honest!

  • Mad Dawg
    Mad Dawg

    Assumption one: Evolution would produce simultaneous, unique life forms. Assign it a value of 0.5

    Assumtion two: We know that designers use common design elements. Assign it a value of 1

    Where's the problem?

  • bohm

    Mad Dawg: riiight. So you are saying that the bible abselutely prohebit that bacteria, plants, bird, fish was created seperately so they do not share a large portion of their DNA, despite the fact that the bible nowhere states this is the case and in fact show God created these animals on different days?
    And you are also saying that to an evolutionist, despite the fact that 99.9% of all species has died out and life seem very very hard to create in the labaratory, she would think it was 50/50 that life originated twice within a short periode and survived to this day? Do you really think you are being interlectually honest to these two ideas?

    But so far so good i guess - you just admitted that you believe with 100% certainty that all life share a common blueprint :-).

    lets make it more interesting. Humans have 46 chromosomes, great apes have 48. Take a look at ken millers video here:


    So let 'O' be the observation

    O = {"A human chromosome looks exactly like two monkey chromosomes fused together, ie. it have two unused telomore DNA sequences in the middle and one unused centromere DNA sequence. The locations are exactly as one would expect in the case of a chromosome fusion."}

    Again, we need P(O|E) and P(O|C) (we let both the creationist and evolutionist be aware of the simple observation that humans and monkeys contain 48 resp. 46 chromosomes). Keep in mind that we are talking about the predictive power of the theory, so no post-hoc explanations - imagine that you needed to argue about these matters 10-20 years ago and didnt have the knowledge you have today.
    So this is my question to you Mad Dawg: How do YOU think they would argue, and what probabilities do YOU think they would assign? Dont just blurt out numbers again, show me their reasoning, and be interlectual honest.

    Here is what i think they would do:

    The Evolutionist perspective: Given evolution there are really only two options: Either a chromosome was split, or two were fused. Splittting would be ruled out because it would have to had happened in all the monkeys seperately, but a fusion would only have had to have happened in the human. something might have happened to the telomeric/centromeric structure, but what remains of it would need to be in the exact same locations. Since there are few processes to remove junk DNA, he would expect allmost all of it to remain, perhaps with a few point mutations. Thus I would assign a very high probability to P(O|E). In reality, what happened was that some evolutionist began to search actively for this structure, and guess what they found...

    The Creationist perspective: Well, we actually DO know what many (most?) creationists argued: humans and monkeys have different number of chromosomes, this show they were created as seperate beings! (ie. P(O|C) ~ 0) i actually had this one thrown after me by a jw a few months ago, so dont try to deny it! But if we calmed down the creationist and had him run through the different options, i think this is what you would get:

    • They were just created this way. Humans have 46 chromosomes with the usual telomeric/centromeric structure, monkeys have 48. This would be a death-blow to evolution, but would be (i think) the most reasonable explanation when all you had was the God-hypothesis.
    • God may have reused two monkey chromosomes in a human chromosome (the creationist i talked to thought that idea was stupid...). How?
      First off he could have split the extra chromosome into pieces and scattered it all over the human genomen where it fitted.
    • Secondly, he could just have spliced them together.
    • Why keep the telomeric/centromeric structure intact? to fool evolutionists and to hide there is a designer? If he wanted to keep the telomeres/centromers, how can we predict their locations? Because God is lazy and dont want to move them around? Why keep two telomeres instead of just one? lots and lots of unanswered questions. 10 years ago, would you have argued that God had made the genomen exactly like it had evolved, or would you just have gone with explanation 1?
    • While we are at it - if we (for some reason!) insist on explaining away the fact that humans and monkeys have different number of chromosomes by them having the same basic chromosomes just rearranged (why would a creationist even begin to consider this?), we might as well consider that the monkey-kinds 48 chromosome come from splitting up one human chromosome. Why is splitting up a human chromosome into 2 monkey chromosomes ruled out? We also need to include this option in our considerations.

    So as you can see there are a number of different options that i dont see how a creationist could rule out. The most dangerous part (in terms of lovering P(O|C)) is the fact the EXACT locations of the telomeres and centromeres are predicted. Where do you find that in the bible? In any case, P(O|C) is, imho, very low, and the same argument as before applies.

  • Razziel

    I do not know much about the relation between sedimentary layers and fossils contained therein beyond common sense and what's been posted in this thread. But from what's been posted, this doesn't look like circular logic to me. It looks like an unconstrained optimization problem, which on the surface, yes, looks like circular logic, but is not.

    I deal with these types of problems a lot in engineering. You know there is a relationship between variable A & B through several other variables. But you don't know what the values of A & B are, or rarely any of the other variables for that matter. And unfortunately, your job is to find out what the best values of A & B are. But you don't have a reference point to start from, so A & B can be an infinite number of values.

    I have to go to work and don't have time now to extrapolate on the math, but basically there are many valid ways to find the values of A & B. (The oldest probably being the golden-section search, and newton's method) They all involve initial guesses, and using that initial guess to recalculate the initial guess generally with an independent variable(s). Through several iterations, the calculated values for A & B will converge close to the real values of A & B.

    On the surface that looks like circular logic, since you used A to find B and B to find A, when you didn't know the true values for either. But it's not. It's using a mathematical relationship to identify maximal/minimal values which correspond to the true values you're looking for. In this case, I would infer the key/index fossils are those which are put into the unconstrained optimization equations. By using multiple fossils, the convergence of calculated values would be even closer to the true values.

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