Thursday, October 1, 2015

Evidence For Dummies

I have previously discussed evidence in terms of its value in providing epistemological support for belief.  Victor Reppert takes a Bayesian view of evidence:
I understand evidence in Bayesian terms. For me, X is evidence for Y just in case X is more likely to exist given Y than given not-Y. By this definition, something can have evidence for it and be false. - Reppert
That's great.  It almost sounds as if he has justification for his beliefs, but in reality, he's just pulling the wool over the eyes of his readers.  Taking a Bayesian view of evidence is good, but it's only part of the picture, as he admits.  When analyzing evidence, you need to find the hypothesis that best accounts for all the available facts.  This is known as a scientific approach to evaluating evidence.  If there are any facts that tend to disconfirm the hypothesis, they can't be ignored (which is what theists tend to do).  Perhaps a different hypothesis would  work better - one that is arrived at by taking a more objective view of the evidence

Let's take an example.  Consider a murder scene, where the victim is found with his throat cut.  He is found in the middle of an open field that is covered with fresh snow.  There is exactly one set of footprints in the vicinity - the footprints of a young child - that lead to the victim, and away again.  A rookie detective forms the hypothesis that a young child committed the murder.  From a Bayesisan perspective, we can all agree that it is in fact more likely that we would find a child's footprints given that the child committed the murder than if the child had not committed the murder.  So the footprints are indeed evidence for this hypothesis.  But fortunately, we also have a seasoned detective on the scene who is able to look beyond that one simple piece of evidence, and take other facts into consideration.  For one thing, he notices that there are no footprints from the victim himself, and no footprints that indicate any kind of skirmish or struggle.  He notices that there is no blood on top of the snow, but there is blood on the ground beneath the snow.  As a result of these facts, he forms a different hypothesis: that the murder was committed before the snow fell, and a child came along later and found the body.  Which hypothesis better explains all of the available facts?

How about another example?  Here's a fact: some people believe in fairies.  Assume we have a hypothesis that fairies exist, and it is supported by the "evidence" that people believe in them.  The Bayesian view of evidence tells us that it is more likely that there will be people who believe in fairies if they actually exist than if they don't.  So the fact that there are people who believe in fairies counts as evidence for the existence of fairies.  True enough.  But is that evidence good evidence?  Is it sufficient to justify belief in fairies?  Hardly.  There are also people who don't believe in fairies, and you can just as well say that their non-belief is evidence for the non-existence of fairies.  So which of these hypotheses is right?  Without taking all the available information into account, you have no good basis for judgment.  You can cherry-pick a single fact - that some people believe in fairies - and use that in your Beyesian analysis of the evidence to support your hypothesis that fairies exist.  Or you can take a broader, more objective view.

Here are some things Victor considers to be reason for his belief in God, and more likely to be true if god exists:
1) The fact that we can reason about the world. The fact that it is even possible to go from evidence to a conclusion. If this isn't possible, then science isn't even possible. But that implies that our acts of reasoning are governed by the laws of logic, as opposed to the laws of physics. But naturalism says the laws of physics govern everything, and the laws of logic are superfluous as an explanation for any event in the universe.
This is based on the unjustified (and unscientific) assumption that reason can't arise from nature.  He assumes that "laws of logic" are different and separate from the laws of nature, and that they have their own causal efficacy.  He needs to read up on cognitive science, and start paying attention to the vast wealth of evidence that he has so far stubbornly refused to acknowledge.
2) That there are stable laws of nature, so that the distant past resembles the recent past. It's easy to imagine an atheistic world with no stability at all, where the laws keep changing for no reason. Why is that not the actual world?
It's also easy to imagine a world created by supernatural powers where the laws of nature don't apply.  It seems to me that the laws of nature are more indicative of naturalism than of supernaturalism.  To think that the natural behavior of the world somehow implies supernatural powers is truly a leap of logic.  To say that the laws of nature are more likely to be true given a supernatural foundation is a lie.
3) The we have just the right cosmic constants for life to emerge.
That's the opinion of believers.  It's not a fact.  Many scientists agree that there could be considerable variation in some of these constants that would still allow for the emergence of life.  But the fact is that life is finely "tuned" (or adapted) to the word in which it exists.
4) That DNA allows for gradual change, as opposed to being completely static or so radically changeable that it is completely unpredictable.
It's hard to see how this constitutes evidence for God at all.  The fact is that in the long run, we can't predict where evolutionary change will lead.  In particular, we don't know that our descendants will continue to have the same level of cognitive function that we have.  Some might even argue that it has already started to decline.  What does that tell us about God?
5) That monotheism arose against all odds in a polytheistic world in a country that hardly qualifies as a world superpower, and that it persisted in spite of the efforts of the superpowers like Assyria, Babylon, the Seleucids, and the Romans, to get it to assimilate into a polytheistic culture.
It is undeniably true that the Old Testament contains many remnants of its polytheistic origins.  But Abrahamic monotheism was heavily influenced by other religions of the period (around 650 BCE), including Zoroastrianism and Egyptian monotheistic cults.  To say that this happened "against all odds" denies the factual information.
6) That the disciples of Jesus got in the faces of those responsible for Jesus's crucifixion and told them that the Jesus they crucified was Lord and God, and lived to tell the tale and found Christianity. (If they killed Jesus, they can kill you too).
This is nothing but hearsay.  Evidence should be based on facts..
7) That archaeology has discovered that if Luke was writing a story about the founding of Christianity, it wrote it in such a way that the "research" for his "fictional" story was corroborated centuries later by archaeology, "research" that would have required him to know all sorts of detail from Jerusalem to Malta at just the right time in the first century.
All we can discern from the archaeological findings is that the author of those stories had some knowledge of the place and its recent history.  But the gospels also contain significant discrepancies between them, as well as discrepancies with known historical information.
8) That Christianity became the dominant religion of an empire in spite of getting no help, and intermittent persecution, from the political leaders of that empire, for nearly three centuries.
No help?  Does Victor suppose that Constantine imposing Christianity as the state religion played no role in its rise to dominance?

Victor pretends to have a solid foundation for his beliefs.  But he systematically ignores factual information and evidence that doesn't support that belief.  That's the only way he can conclude that all of these pieces of "evidence" are more likely to be true if God exists than if God doesn't exist.   That's the only way he and his fellow Christians can continue to believe their fairy tales in the face of everything we know in this modern era of scientific and historical knowledge.


  1. For the first four centuries, Christianity was a dog's breakfast of 'isms', Marcianism, Cerinthianism, docetism, Montanism, gnosticism, Arianism, Manichaeism, Ebionism, to name just a few. There was no consistent narrative for what purported to be the ' one true' christianity. It took Constantine in 325 to butt a whole lot of heads together along with their
    squabbling competing and conflicting ideologies and force them eventually to cobble together the Nicene Creed - that religious shibboleth designed by committee to test sectarian allegiance and obedience from then on. Not a good look by any stretch for an apparently historical account founded on nothing but fact, evidence and proofs. But as any reasonable and knowledgeable scholar knows this did not put an end to the raft of schisms and isms that characterise the historical reality of perpetuating the Christian mythos. Today, the evidence is even more compelling that the historical claims for the origination of the Christian belief system is largely founded on hearsay and legendising. As Professor Robert Funk, Bible scholar, and formerly Chairman of the graduate department of religion at Vanderbilt University eruditely noted:

    "If the evidence supports the historical accuracy of the gospels, where is the need for faith? And if the historical reliability of the gospels is so obvious, why have so many scholars failed to appreciate the incontestable nature of the evidence?

    Answer? There never was any.

    1. And I love Bob's two cents worth:

      "1) The evidence we do have (mainly, the testimony of the Apostles) is fairly strong. For me, it satisfies all by itself. That's the "positive" evidence. But then, we also have

      2) the fact that, despite 2000 years of decidedly hostile attempts, no one has ever come up with an alternative explanation to the details that are not in dispute, which can stand against the least scrutiny. They all fail Big Time - every one. That's the "negative" evidence."

      Only if you ignore the facts, Bob. As Papalinton said of your supposed strong evidence: There never was any. But go on ignoring the facts and believing your hearsay stories without question - without any hint of objectivity - and you can believe anything you want.

    2. And 2 cents is about all that Bob's contribution is worth. I would like to ask Bob, Victor, et al, point me to where I can access the actual testimony of the Apostles? If Bob is referring to the gospels, one thing that all bona fide biblical scholars knows is that all four gospels were written by anonymous authors. Any suggestion about whom they might be is thoroughly speculative with no basis in fact. The best that genuine biblical scholars can make of the account is that some unknown persons wrote something about what they thought the apostles might have believed and attributed those purported beliefs to those apostles. According to a count of heads from the bible there were at least 21 apostles:

      1. Simon Peter (Matt. 10:2)
      2. Andrew (Matt. 10:2)
      3. James the son of Zebedee (Matt. 10:2)
      4. John (Matt. 10:2)
      5. Philip (Matt. 10:3)
      6. Bartholomew (Matt. 10:3)
      7. Thomas (Matt. 10:3)
      8. Matthew (Matt. 10:3)
      9. James the son of Alphaeus (Matt. 10:3)
      10. Thaddaeus (Matt. 10:3), or Judas the son of James (Luke 6:16)
      11. Simon the Zealot (Matt. 10:4)
      12. Judas Iscariot (Matt. 10:4)
      13. Matthias (Acts 1:26)
      14. Paul (Gal. 1:1)
      15. Barnabas (1 Cor. 9:5-6, Acts 14:4, 14)
      16. Andronicus (Rom. 16:7)
      17. Junias (Rom. 16:7)
      18. James, the Lord's brother (Gal. 1:19)
      19. Silas (Silvanus) (1 Thess. 1:1, 2:6)
      20. Timothy (1 Thess. 1:1, 2:6)
      21. Unnamed apostles (1 Cor. 15:7)

      And ironically, one of the apostles, Paul, never even knew anything at all about the earthly Jesus, where he lived, what he did, let alone not even meet the guy.

      And when it is convenient, with even a scintilla of a perceived increase in utility value, to apologists like Bob, apostle is substitutably synonymous with disciple. That is, apostles can segue into disciples and vice-versa at the drop of a hat when it suits their argument.

      Let's face it, whatever Bob claims as apostolic testimony is a chimera, a mirage, a pantomime of the intellect.

    3. This comment has been removed by the author.

    4. Indeed the Christianity we now have, should rightly have been called, Paulianity. And it was during the years of Roman occupation of the Middle East that Paulianity ostensibly challenged its biggest rival, the orthodoxy of the then prevailing tradition of religious hokum, Mithraism.

      I think it historically correct that one can rightly conclude that Paul is the principal architect, the rightful heir and prophet of Christianity, just as we can correctly make the historical observation that Muhammad was the chief architect and prophet of Islam, aping Paul's effort some six hundred years later. Ironically, both used the same text that the Jews cobbled together even centuries earlier, with a view to reshaping the old mythos to match the cultural imperatives of their particular times.

      And as history has clearly shown us, with the myriad of dead and dying religions, religions do have a limited and finite shelf-life, Christianity no less so.

    5. I couldn't agree more. How does this guy Paul, who never met Jesus, get to set himself up as the expert on his teachings and the founder of a whole new religion based on his own ideas about what Jesus said, while there was no unanimity on any of this at the time? Why didn't it fall to one of the actual disciples who listened to (and presumably understood) Jesus over an extended period? I find this baffling.

    6. Paul spent most of his lifetime putting out brushfires that sprang up all over the Mediterranean as people began initiating their own interpretations that didn't align with and in the absence of his particular and peculiar christian-think. Indeed the New Testament is little more than a Pauline snakes-and-ladders journey hosing down those ideas that ran counter to his construct of the jesus theme. [construct - (noun): an idea or theory containing various conceptual elements, typically one considered to be subjective and not based on empirical evidence]

  2. Victor says:

    "My overall picture of epistemological justification goes something like this. We all start from different places, and have different initial dispositions with respect to the world as we experience it. Then, we acquire further information. Historically people have tried to pull their model of the world apart and start only from certain basics, and believe only what can be built up from there, but I don't think that's necessary, especially when the people who say we have to do it disagree about what has to be in the base. I think it makes more sense to adjust the beliefs we have as we go along and move incrementally toward consensus as evidence comes in. And with some things, the hope of consensus is pretty slight in the foreseeable future, so we are going to keep disagreeing. I think, for example, that atheists and theists are here to stay for a long time, and the fact that we aren't closing in on agreement does not necessarily mean that one side or the other is just being stubborn or delusional. I would say it's because the issue is too complex and there are too many parameters to it to be sure that we have considered everything, and fairly. It's easy to come up with motives for our opponents, but that in itself proves nothing whatsoever."

    If there are too many parameters to be sure you have them covered, how can you then go on to assign prior probabilities in your Bayesian analysis with sufficient confidence to decide the issue in your mind? Even worse, if you have been informed that there are pertinent facts that you haven't considered (for example, regarding the biological basis of cognition), wouldn't it be prudent to refrain from tying to assign prior probabilities until you make an honest effort to examine them? This is why I say you are pulling the wool over the eyes of your readers. Bayesian analysis requires an objective view of the evidence and an assignment of relative probabilities based on understanding that evidence. It isn't sufficient to say something is much more probable simply because you really, really believe it.

  3. I think it is an obfuscatory concession on Victor's part. Imagining "the issue" too complex with too many parameters simply means the attempt to inveigle primitive theological schema into today's evidence-based naturalistic and scientific knowledge paradigm, out of which our greatest discoveries have emerged, is largely a no go. It is becoming clearer, with each new discovery, with each new finding made, corroborated and confirmed, be it through the hard sciences [physics, chemistry, biology] or the soft sciences [sociology, psychology], Professor David Eller's astute observation is a salutary reminder that:

    "....religions do not and cannot progress the way that, say, science can progress. When science progresses, it abandons old and false ideas. Once we discovered oxygen and the principles of combustion, we stopped thinking that there was a substance called phlogiston. Once we discovered that the earth is round, we stopped thinking that it is flat. Science and reason are substitutive and eliminative: new ideas replace old ideas. Religion is additive and/or schismatic: new ideas proliferate alongside old ideas. For instance, the development of Protestantism did not put an end to Catholicism, and the development of Christianity did not put an end to Judaism. With science, we get better. With religion, we get more."

    What Dr Reppert characterises as a complex issue and with too many parameters is best viewed for what it is, the futile attempt at fitting the Christian theological/philosophical square peg into the naturalistic/scientific [w]hole. He makes the irredeemably problematic assumption that theological knowledge is on par with, of the same order of explanatory power as, scientific knowledge.

    It's not a matter of his not getting it. He chooses not to get it: "And with some things, the hope of consensus is pretty slight in the foreseeable future, so we are going to keep disagreeing."

    1. That's a good point. It shows that no matter how much Christians insist that their religion is compatible with science, they are swimming against the tide of scientific discovery. If they claim that there are supernatural influences on the physical world, they are denying the regularity of nature which is the very basis of science, stripping it of its power to explain natural phenomena and produce reliable theories that are consistent with observation. But it is their claims that defy observation. It is their claims that can't be corroborated or confirmed. How is that compatible with science?