On Probability and Possibility

Many fundamentalists have what is called "certitude". According to Webster's New World College Dictionary, certitude is the feeling of "absolute sureness or conviction". "Certitude" is different from "certainty". Webster's gives certainty as the "state or fact of being certain". The difference is this: the latter is an objective statement of a situation while the former is a subjective description of one person's views. Thus feeling, "knowing in your heart", that one is right (certitude) is different from being able to demonstrate it (certainty).

Where can we find certainty? Strictly speaking, the only certainties we have are in the fields of mathematics and logic. But these are "mental constructs" and their deductive certainty comes from the fact that we define certainty into it. Thus "1+1 = 2" is certainly true because we defined "2" as the next number after "1". (I might add, as Godel's incompleteness theorem shows, that even here the knowledge [within a single deductive system] will always be incomplete) (Note also that "1+1 = 1" is also "certainly true" in Boolean algebra!) Mathematics and logic also allows us to pronounce, with certainty, the impossibility of some concepts. These include concepts like a square circle or a four sided triangle. The reader will note that it is simply not possible to imagine these! In other words we can be certain that square circles and four sided triangles cannot exist.

When it comes to the empirical world, even this incomplete certainty disappears. Let us take, as an example, this statement of fact:

The Sun will rise from the east tomorrow.

This is, admittedly, a rather quaint geocentric rendering but it would suffice for our current purpose. Now our belief that this statement is true comes from the fact that all our experiences in the past and in recorded history have shown that the sun had risen from the east without fail. Furthermore our collection of the habits of nature summarized in physics (conservation of angular momentum and the law of gravitation) supports this fact.

However as David Hume (1711-1776) showed a long time ago, all these findings, in support of our certainty that the sun will rise from the east tomorrow, are taken from the past. There is no logical contradiction in thinking that the future may be different. For instance, I can say:

The Sun will rise from the west tomorrow.

and can imagine it, in a way that I cannot imagine a four sided triangle! So, strictly speaking, anything that is not logically contradictory is, in principle, possible.

That's not where the analysis ends though. For if we believe anything is possible than we have no way of deciding anything. The reason why we take the fact that the sun will rise from the east tomorrow as virtually certain is that our past experiences, couple with our knowledge of science and history, give us a high confidence level (a very high probability) that the event will happen again tomorrow. Indeed I would classify anyone denying this as being delusional. Thus we are justified in saying that this is one thing that approaches certainty. Note how possibility, apart from setting an initial counter-example, plays no role at all in the decision making process.

Similarly historical reconstructions are all done on the basis of evaluation of the evidence and the probability of the various scenarios. This is how reason works, in science, in history and in life.

This is not the case with fundamentalist apologetic "reasoning". Almost invariably, fundamentalist apologists "reason" from the basis of possibility.

One example of this is from the recent fundamentalist bestseller, Lee Strobel's The Case for Christ (Zondervan 1998), in discussing the conflicting genealogies of Jesus in Matthew and Luke (Matt 1:1-16 and Luke 3:23-32). Strobel quoted Craig Blomberg [1] as suggesting "two options" to "resolve" this difficulty: the first option is that Luke's genealogy is of Mary, while Matthew's is of Joseph, the second "option" is the "levirate" explanation, i.e. that while both genealogies traces Joseph's ancestries, one traces the legal ancestry (levirate) while the other traces his biological one. These options, according to Strobel, provide "rational explanations" and give a "reasonable harmonization" of the gospel accounts.

Note the fallacy here. Blomberg was merely providing additional possibilities (which are themselves mutually exclusive!) that may account for the discrepancy in genealogies. The third possibility, that this indeed is a contradiction, has not been proven wrong (i.e. shown to be improbable). Thus most scholars would take these possibilities as a starting point for analysis (i.e. to look into the probability of various explanations) not the ending or the resolution of a problem, as Blomberg and Strobel clearly intended it to be. [a]

The root cause of the fallacy is simple. Embedded within this method of "reasoning" is the belief (certitude) that the Bible is inerrant and the moment there are possible explanations for various "difficulties", the problem is considered solved! This is not how things work in reasoned discourse. (Remember that it is "possible" that the sun may rise from the west tomorrow!)

The reader will notice that in many sections on Biblical contradictions and errors I have merely provided the contradictions themselves (albeit sometimes with links to a more detailed analysis in other postings in my website) without considering fundamentalist defenses. The reason is simple, fundamentalist defenses are almost invariably based on possibility not probability, and most times are simply too far fetched to require serious consideration; in other words while their suggestions may be possible it will be seen almost immediately to be most improbable.[b]

This "defense from possibility" permeates fundamentalist thought on the Bible and the "historical" Jesus. I leave the last word to Dr. Robert Miller, a fellow of the Jesus Seminar:

[T]he concept of possibility is not very helpful in historical matters. Endless historical scenarios can be concocted, and virtually all of them are possible, even the weirdest and most fantastic. That's why to say that a certain scenario is possible almost always is to say nothing about it at all. ...But it's crucial to make the distinction between possibility and probability because very different criteria apply in each case. To be historically possible, something only needs to be imaginable. However, for something to be historically probable means that there is some evidence for it. Not everyone in the historical Jesus discussion seems aware of this distinction, for we often read statements like "Isn't it possible that Jesus...?" Fill in the blank with any scenario you like, no matter how you like: the answer will always be yes.[2]

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Notes

References

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