Cumulative case argument

Cumulative Case Argument

We humans seem primed for religious belief. Even skeptics stand at the precipice. All skeptics require is one good argument. But no one has ever come up with a single good argument.

Religious apologists respond to the lack of good arguments by concocting as many arguments as they can. The arguments are typi­cally subtle variations on existing arguments, embellished with a clever twist to circumvent the latest skeptical rejoinder. Some, including William Lane Craig’s version of the contingency argument, simply engage in deceptive wordplay.

The upshot of this proliferation of apologetic arguments is that authors like me are forced to write longer books than we otherwise would. And readers like you must slog through a swamp of argu­ments with a great measure of diligence.

That’s not an altogether bad thing. The unexamined life is prob­ably not as enriched as the examined life. Notice that I don’t go as far as Socrates, who in Plato’s Apology declared that the unexamined life is not worth living. It seems to me that life is worth living even if one never bothers to think deeply. If you ever see me attached to life support and someone says that I’m in a vegetative state, please don’t let them pull the plug. I might be having a really good time.

Since we’re embracing the examined life, let’s slog on. We’ve already ex­amined every major theological argument. The cumulative case argument, which we’ll now consider, is the theologians’ last-ditch effort to snatch victory from the jaws of defeat.

The cumu­lative case argument holds that, though each natural theology argu­ment is imperfect, each contributes at least marginally toward justify­ing belief in God. The claim is that these arguments collectively sum up to an adequate case for God.

The cumulative case argument can add to its tally every apologetic argument that can be assigned a probability. Apologists might sur­mise, for instance, that the design argument has, say, a 0.2 probability (a 20 percent chance) of being correct. Perhaps the moral argument has a 0.15 probability. Combined, these two arguments have a 0.35 probability.

The apolo­gists’ goal would be to accumulate at least enough probability points to cross the 0.5 probability threshold. Assigning these proba­bil­ities to each argument would, of course, be a challeng­ing and con­ten­tious project.

A Christian apologist will select only those apologetic arguments that work toward proving a Christian con­ception of god. An argument specifical­ly for Islam would constitute an argu­ment against Christian­ity and vice versa.

The apologist will thus include as broad an array of argument as possible while avoiding mutually destructive arguments. The apolo­gist will adopt a definition of god generic enough to be compatible with the entire set of arguments in­cluded in the mix. In other words, a cumulative argument will be stronger if it strives to estab­lish only a god who is the lowest common denominator.

Once apologists have tallied all the probability points of their pro-God arguments, the next step is to subtract probability points for each counter-apologetic argument. For instance, if someone argued that God specially designed the human skeletal system, the counter-argument would likely cite evolutionary theory, which educated people deem highly probable.

As you can see, it is arithmetically impossible for a collec­tion of losing pro-God arguments to be summed up to build a winning case unless we exclude the probabilities of the anti-God arguments. This means that the cumu­lative case argument cannot be persuasive to anyone who doesn’t already believe that the pro-God arguments have the edge.

If any counter-apologetic argument reveals the logical impossi­bility of the god being proposed, the cumulative case cata­strophically fails. Such devastating counter-arguments do indeed exist, as explained in Chapter 11 of Religion Refuted, but for present purposes, we’ll ignore them.

Let’s consider an example of a cumulative case argument. Sup­pose I hypothesize that invisible leprechauns with bad hair are secretly stealing socks from sock drawers and laundry baskets. I could argue that every missing sock is evidence of these leprechauns.

A missing sock may not sound to you like good evidence for in­visi­ble leprechauns. That’s okay. It doesn’t need to be good evidence. If a missing sock adds even a miniscule amount of credence to my in­visible leprechaun hypothesis, I can build a cumulative case. Enough missing socks over time will add up to a compel­ling argu­ment for the existence of the lepre­chauns.

According to my calculations, even if a missing sock contributes a probability of only one billionth of one percent to my leprechaun hypothesis, and even if the vast majority of people on Earth never lost a single sock and the rest of us lost only one pair of socks during our entire lifespans, the existence of the sock-stealing leprechauns would have accumulated enough probabil­ity points by this time in human history to make the case for lepre­chauns more probably true than false.

If I hypothesize that these leprechauns also make people drop things, then every time someone drops something I chalk up more proof that the leprechauns are real. I can keep adding qualities, attributes, and bad habits to the leprechauns. Oddly enough, the more elaborate and fanciful I make my description of the lepre­chauns, the easier it be­comes to prove their existence.

Clearly, there’s something wrong with this approach. Let’s explore why the cumulative case for leprechauns fails and then we can see if this same kind of failure afflicts the cumulative case for Jehovah.

In the leprechaun case, the fundamental problem appears to be that my evidence (missing socks) seems irrelevant to the conclusion (leprechauns). Why should a missing sock be accepted as evidence for invisible leprechauns? It’s a non sequitur. If we concede that a missing sock counts as even a tiny fraction of one percent of a case for invisible leprechauns, then we have established the fatal principle that enough missing socks amounts to a slam-dunk case for lepre­chauns.

We risk committing the same mistake in the case for Jehovah. When an apologetic argument for Jehovah fails, it fails completely. We can’t assume that something is evidence, even extraordinarily weak evidence, unless there’s a causal link between that evidence and the purported conclusion.

That’s the failure point of the cumula­tive case argument. Propo­nents of a cumu­lative case exploit our natural tendency to conflate our residual uncertainty when appraising the merits of an apologetic argument with its degree of merit.

A Christian apologist would almost certainly scoff at my compari­son of Jehovah to invisible leprechauns. The apologist might rec­ommend that we compare the case for Jehovah to the case for an event where we’re accustomed to thinking in probabilistic terms—perhaps, say, a home burglary. A creaking noise from behind a house, a window that is slightly ajar, and a crowbar lying on the window seal bolster the case that a home burglary was in progress. The case for Jehovah is thought to bear more resemblance to this burglary case than to the leprechaun case.

But that’s wrong. We can build a cumulative case for a home burglary because each of the individual pieces of evidence for the burglary is uncontested (or likely so) and these individual pieces of evidence combine to form a cohesive, unified narrative. In contrast, each apologetic argument is highly contested and each is a stand-alone argument rather than an integral part of a cohesive narrative.

I’m not arguing that a cumulative case can never be made in de­fense of religion. A cumulative case is appropriate when one is, say, building an argument that there was a historical Jesus. Documents such as the Gospel of Luke and the writings of Tacitus can converge toward the conclusion that ancient people sincerely believed that Jesus was a historical person. The Luke and Tacitus documents are comparable to the creaking noise, crowbar, and open window in that they are extant pieces of evidence. Moreover, there’s an estab­lished, though admittedly imperfect, causal link between real-world facts and written human testimony concerning those facts.

In contrast, the “missing socks” argument is a stand-alone argu­ment with no history as causally related to the existence of invisible leprechauns. Likewise, the cosmological and fine-tuning arguments are stand-alone arguments with no history as causally related to the existence of any supernatural being.

Because leprechauns are not causally linked to missing socks, the leprechaun hypothesis can’t be assigned a probability greater than zero. Likewise, the apologetic arguments put forward to prove Jehovah can’t be assigned a probability greater than zero.

This explains why prosecutors can build a cumulative case that a burglary was in progress and why historians can build a cumulative case that Jesus existed, whereas we cannot build a cumulative case for beings like gods and invisible leprechauns with bad hair.

All the failed arguments for God should indeed have a cumulative effect on our judgment about the case for God, but the effect is the reverse of what apologists suggest. The repeated failures by intel­ligent men and women throughout history to come up with a single compelling argument for God, despite their most passionate com­mitment to the project, indicates that the project may be hopeless. This, in turn, strengthens the case that supernatu­ral beliefs are based on an inaccu­rate view of the cosmos. Perhaps we should call this the cumu­lative case for atheism.



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