Most of the responses I received about my recent article on intelligent design were frankly too irrational to deserve a reply.  However, several of them did seem to indicate that I had failed to explicitly state my rationale for regarding 'Statement 1' as scientific or for requiring statistical justification for the evolutionary concept of the spontaneous origin of life. My arguments are as follows:

(a) The realm of scientific speculation neither postulates nor excludes the existence of an intelligent force beyond (and responsible for) the laws of nature. If an overwhelmingly improbable event occurs, a scientist must at least acknowledge that the apparent absence of a natural explanation makes the postulation of a para—natural explanation worth considering. Stating (as one reader did) that the existence of a para—natural intelligence is 'so infinitesimal as to be excludable' is an irrational and unsubstantiateable dogma,  unworthy of a scientist. 

(b) The current evolutionary explanation of the spontaneous origin of life (SOL) is that it occurred as a random coincidence of a large number of fortuitous events in the primordial Miller—Urey soup.  The opposing 'intelligent design' explanation, which might be called the unnatural origin of life (UOL) hypothesis, is that a spontaneous origin is so incredibly unlikely that some other explanation, beyond the laws of nature as we understand them, is required. These two hypotheses are logical opposites of each other.

(c) A decision between them is possible by a statistical estimate of the number of times that a fortuitous creation of a viable self—sustaining organism (e.g. a cell capable of living and multiplying in the soup) is likely to have occurred during the Earth's history. If that number turns out to be (say) 10[exp 12] (i.e. a trillion), then the SOL theory is scientifically plausible and the UOL theory should be relegated to the realm of philosophy.  On the other hand, if the answer is 10[exp—12), then the SOL theory is in serious trouble and the UOL theory is, by default, a legitimate alternative hypothesis. If the answer comes out 1, then, even allowing for the wide range of uncertainty, no conclusion can be reached and neither the SOL nor the UOL theory can be considered invalid or beyond the scope of science.

(d) Such calculations are extremely difficult but not impossible.  The first approach I suggested would use a minimal—gene minimal—function bacterium as a model, perhaps one of the iron— or sulfur—oxidizing bacteria.  A feasible model for the second, or 'protolife', approach might be to construct a hypothetical least—common—denominator organism by using only those genes that are common to virtually all types of cells, adding only those additional genes necessary to provide a self—consistent metabolic—pathway diagram. In either case, the biggest stumbling block would be the formation of membranes around the bundles of DNA or RNA to form organelles. I would get around this step, as a zero—order approximation, assuming that it's not the critical rate—limiting step and leaving it out of my calculations.

(e) Until such statistical calculations are made, a scientist has no right either to exclude the UOL hypothesis as a possible explanation for the origin of life or to regard the SOL hypothesis as a proven or even probable fact.

(f) Even if such calculations are made and the SOL hypothesis demonstrated to be virtually impossible, the UOL hypothesis—like any scientific hypothesis—must always be considered tentative. This is because future scientific discoveries may eventually disclose a hitherto—unsuspected mechanism that would change the statistics and render the SOL hypothesis plausible.
I hope these explanations will satisfy most of the readers who expressed concern.

Paul Shlichta is a research scientist who is currently writing a Manual of Methods. His scientific credentials may be viewed here.