In my prior article on the nature of faith and its role in human relationships, the linchpin concept was that of certainty. As I discussed, neither my fiance nor I are – or ever could be – mathematically certain that our pictures of each other as compatible spouses are accurate. I may say things such as “I am certain she is the one for me“, or she may say “I am certain that Ben is a good father and an honest person“, but these are hyperbole. Mathematical certainty, in the sense of zero probability of a proposition being actually untrue, is only possible…with mathematics.
Saying that we are “certain” of our relationships is simply a colloquial way of stating our great faith in them. In more technical terms: we are stating our view of the high probability that e.g. “she is the one for me” or “Ben is an honest person“. Of course, nothing would be more robotic than to say “The probability that Ben is not an honest person is 1 in 3,720″, and so we speak plainly and just say “Ben is a completely honest person“. And yes, that was a Star Wars C3PO reference…
But since certainty is impossible except in the conceptual realm of mathematical tautologies – and probability is the measure that we use in even the most important areas of our life – it would pay to dig deeper into the concept of probability, to see in what other areas of life it operates, and what it can tell us about our “epistemology“, or our sense of how knowledge is gained.
Bayes to the Rescue
Thomas Bayes was an 18th century English statistician and Presbyterian minister. He gained fame after his death for his theorem which expressed how a degree of belief in the truth of a proposition, expressed as a probability, should rationally change to account for the availability of evidence for that proposition. In other words – calling something “true” is a judgement call that we make after a certain tipping point of evidence is reached.
For example, my own belief that my girlfriend, Emily, was a good match for me as a mate, was weakened significantly when I came to belief in Jesus Christ as God and redeemer, and after I accepted all of Christ’s & His Church’s teachings into my heart. The new “evidence” in this case, wasn’t a change in her behavior or personality, but instead other evidence about the nature of the world and reality (God, etc.), as well as how my own changed worldview stood in new contrast to Emily’s. This is the main reason that this crisis of faith – as I called it in the prior post – was so especially painful to Emily. She hadn’t changed, only I had. And I had done it largely in secret for many months, without letting her in on the process. She was surprised and dismayed that the change was so drastic and apparently so sudden.
So in the Bayesian sense, the probability of my life-long compatibility with Emily was weakened for a time – perhaps from ~96% to somewhere south of 80% (I’m just spitballing here). I did eventually recover that high probability in belief in our compatibility – that strong faith – but only after each of us brought more evidence to light in the “case for mutual compatibility“.
It’s all Subjective
A key feature in Bayesian theory is subjectivity. Probability, seen through the Bayesian lens, is actually a measure of the degree of belief or confidence (or certainty) that a person has in the truth of a proposition. There are some statisticians who dispute this approach (calling themselves “objectivists”), but the subjectivist lens is still not that controversial.
Subjectivity makes total sense when we think of any proposition, e.g. in science or politics, where heated debate exists.
For example, most scientists (though fewer every year) believe that neo-Darwinian theory of evolution fully explains life’s astounding complexity on Earth. Some other scientists believe that an Intelligent Designer – and nothing else – can explain the origin of biological information in genetic and epigenetic forms, from which the subsequent astounding complexity of life on Earth is made possible.
What are these two opposing camps warring over? They are warring over probabilities. Each camp consists of individuals who have independently assessed evidence against candidate explanations for the cause of life’s complexity and abundance, and then coalesced together with other like-minded scientists around a mostly shared subjective belief in the probability that 1) blind chance did it all or 2) intelligence did it all (or at least guided it all).
Now to say of scientists that their beliefs about the state of the universe – their treasured theories – are subjective and not objective – would be taken as a grave offense. “Science is objective truth!“, we often hear.
But with science’s long track record of striving-but-never-achieving certainty – that is, the error/revision/refinement process we lovingly call the Scientific Method – and viewed through the Bayesian lens I’ve described – its clear that truth claims made by scientists are not mathematically certain, and thus can only be said to exist on a continuum of probability, but never on the far end of that continuum called “certain“. That far-off land is inhabited only by “2+2=4” and related oddities…
This is why Elon Musk can claim that we’re all living in an alien simulation (ala the Matrix) and not get laughed off the stage. Such a claim is possible – though incredibly improbable (despite his own complaints to the contrary). The very fact that such ideas are admitted into a civil discussion among scientists belies the idea that there is any certainty to scientific knowledge itself, or any knowledge. We all deal with probabilities, all day, all night, all of our lives.
But…maybe this is not actually clear enough? Fine – let’s examine a case outside the love & science realm…
Execute a Man Who “Probably” Did It?
Scott Peterson was convicted in 2004 of the murder of his wife Laci and their unborn son, Conner – on a boat he owned. It was one of the highest profile circumstantial murder cases in recent memory.
Here is the evidence that put him away:
- Peterson had an affair with Amber Fry, to whom he lied that he had “lost his wife”…before Laci was dead
- Peterson faced mounting debts, with indications that the cost of supporting his family caused him stress
- A single hair was found stuck to pliers found on Peterson’s boat, which DNA-matched hair from Laci’s hairbrush
- After Laci’s death, Peterson:
- Added two pornographic channels to his cable TV service days after his wife’s disappearance, indicating that he knew his wife wasn’t coming home
- A few hours after Laci went missing, Peterson lied to her uncle that he spent the day golfing, not fishing
- Expressed interest in selling the house he had shared with Laci
- Traded in her Land Rover for a Dodge pick-up truck
This list of small, individually insignificant facts – as well as a few others like them – convinced the State of California to execute Peterson for double murder.
This also goes to illustrate a key concept of Bayesian probability, which is that evidence – even tiny bits of evidence – mounts up quickly and can flip an initially dodgy explanation/conclusion from very improbable to highly probable.
The cumulative effect of small pieces of evidence has the same effect as a single giant piece of evidence.
In the Bayesian probability framework the scale of evidence is logarithmic – which is to say:
10 pieces of evidence worth $10 == 1 piece of evidence worth $100
Compile a bunch of little pieces of evidence, each amounting to little on its own, but which point toward the same conclusion, and you can convince a jury to kill a man.
This is what makes it so frustrating to hear “But that doesn’t prove anything!” from a Christian skeptic when I offer a single piece of evidence for Christ’s resurrection such as:
The early apostles willingly died for their testimony, and people don’t typically sacrifice their lives for a lie or a delusion
Of course this doesn’t “prove” anything on its own. Its evidence, a small piece at that. “I’m not done“, I usually say to the skeptic. “Be patient, and keep your mind open please?” 🙄
Knee-jerk reactions such as “That proves nothing!” against small pieces of evidence in a circumstantial case have more to do with our current Scientistic age’s thirst for “Knock down arguments“, “Open and shut cases” and the like. To many people, the only qualifying evidence for conclusions that they don’t want to accept, is where the ratio of that evidence to final proof is 1:1. This ratio doesn’t exist in the real world.
We would do well to remind ourselves that, if we could only satisfy our thirst for truth with giant, $100 pieces of evidence, then murderers like Scott Peterson would never get justice.
God Revealed Bit by Bit
So how does all this relate to my own personal belief in God? Because He revealed himself to me and the world in a multitude of ways, none of which is irrefutable on its own as proof – but which all accumulate into an overwhelming case for…
- His very existence in the immaterial realm, and
- His rescue mission to Earth in the person of Jesus Christ approximately 2000 years ago
In this blog I’ve already laid out several ~$20 pieces of evidence toward conclusion #1 here, here, here and here.
In an upcoming post, I will finally catalog the long list of $1 pieces of evidence for Jesus Christ’s resurrection, which current historical and archeological evidence offers.
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