Over on another thread, there has been some discussion (among other things) about whether the concept of CSI must include a calculation of probabilities under all natural processes. There are a number of interesting issues relating to CSI that might be worth exploring in more detail (including Learned Hand’s comments @47 of that thread, and the issues I mentioned @139).

For now, however, I want to simply flag an issue that has been harped on for years by various individuals (Liddle, ribczynski, and in the recent thread, keith s and wd400). In summary, the argument is that without knowing all the probabilities of all possible natural processes we cannot ever be certain that some natural process didn’t produce the biological system in question, say, the bacterial flagellum. And since we cannot be certain that some natural process didn’t do it, then we cannot ever be certain that it was designed.

The primary problem with such an argument is that it pretends to deal in certainties — exhausting all possible natural processes, known and unknown, that might have produced such a system. In practice, it is essentially a claim that unless we are omniscient, we can never conclude design. Apart from the wildly one-sided approach to such a position, it ignores the fact that intelligent design is about drawing reasonable *inferences*. No-one has ever claimed to be able to do an exhaustive analysis of all *possible* natural causes, including those that haven’t been well defined or even thought up yet. Nor does any branch of science proceed on such a basis. Rather, we draw upon what we *do know*, the processes that we are aware of, and then make reasonable inferences. That is why it is called a “design inference,” not a “design deduction” or an “exhaust-all-other-possibilities-before-we-can-say-anything” approach. The inference to design operates, as does all reasonable scientific effort, on the basis of *known* processes.

Part of the discussion on the prior thread has focused on whether a natural process, like Darwinian evolution, has any reasonable probability of producing a complex, functional biological structure such as the bacterial flagellum within the resources of the known universe. For those who don’t have the time or the stomach to wade through all the comments in the prior thread, I offer the following more succinct summary of this particular issue, in the form of a hypothetical (but, unfortunately, very true to life) conversation between an ID Proponent and a Darwinist:

**ID Proponent:** Everyone from Darwin to Dawkins acknowledges that many biological systems *appear *designed. Nevertheless, rather than just assuming design, in order to be scrupulously careful in our analysis we are also going to examine known natural processes to see if they have a realistic chance of forming such biological systems given the resources of the known universe. [ID Proponent adds additional details about specification, etc., and then says:] We’ll call this concept CSI. Now when we look at such biological systems, say, the bacterial flagellum, and do some basic calculations on even the most fundamental informational structures required to construct the system, it appears the system contains CSI.

**Darwinist:** Wait, wait! Your calculation of CSI must include *all *known natural processes. You forgot to include in your calculation my theory, which is that random mutations can be selected and preserved over time to form more complex and more functional structures. We don’t need to form things all at once. The bacterial flagellum came about through slight, successive changes.

**ID Proponent:** Sure. I’m happy to include known natural processes. Have we ever seen something like a bacterial flagellum arise through Darwinian evolution?

**Darwinist:** No. But that is only because it takes too long. Indeed, my theory includes the idea that it takes so long that we *shouldn’t *expect to see such systems arising. Or, alternatively, under a version called “punctuated equilibrium” that it happens quickly and in rare, largely unobserved situations. In either case, we should not expect to see it happen.

**ID Proponent:** Um, that seems pretty convenient, doesn’t it? But OK. Let’s include the probabilities of such a system coming about through Darwinian evolution. What are the odds of the bacterial flagellum arising through your theory of Darwinian evolution?

**Darwinist:** No-one knows. We can’t do the calculation.

**ID Proponent:** Well if there is no well-recognized way of calculating the probabilities of Darwinian evolution producing the bacterial flagellum, then I suppose I can’t calculate it either. However, that . . .

**Darwinist:** Aha! I knew it. You can’t do the calculation! Therefore, your CSI concept is bunk and I win.

**ID proponent: ** Hold on just a minute, let me finish. Let’s think through this. You are telling me that I need to take into account the probabilities of your theory producing the bacterial flagellum, and then you say that under your theory you don’t know what the probabilities are? So what do you want me to include? After all, it is your theory, not mine. I am only interested in known natural processes, so if we don’t know whether your theory has any reasonable probability of producing the system in question then there is nothing to include. At most, I guess we could add a caveat to our calculations that our number doesn’t include the probabilities of Darwinian evolution because no-one knows what those probabilities are. Would that make you happy?

**Darwinist:** No, you *must *include a calculation of probabilities under Darwinian evolution in order for your concept of CSI to be valid. Otherwise, CSI is bunk. You said you were going to include *all *natural processes in your calculation.

**ID Proponent:** As I said, I am willing to include in CSI the probabilities of all known natural processes. But I am not going to make up probabilities for some unknown, unconfirmed, process. Again, if you have some details to offer about your theory that would allow us to include it in the calculation, I’m happy to do so.

**Darwinist: ** Nope. Can’t be done. I’m not going to tell you what the probabilities are under my theory. But if you want to critique my theory and show that my theory isn’t plausible, you’ll have to come up with the probabilities of my theory on your own.

**ID Proponent:** Hang on. If I want to critique your theory I have to *add* some details to your theory that it currently doesn’t have? Shouldn’t you be interested in knowing whether your theory has any reasonable probability of producing something like the bacterial flagellum? Shouldn’t Darwinist theorists be anxiously and studiously analyzing what reasonable probabilities Darwinian evolution can overcome, what it can be expected to produce given the resources of the known universe, the “edge of evolution” so to speak?

**Darwinist:** We don’t need to provide any such calculations because we believe Darwinian evolution did it. And if you can’t provide the calculations for our theory then you can’t critique our theory. Therefore your idea of CSI is bunk and we win!