Reading the NAS book on Science, Evolution, and Creationism, I was struck by the fact that naturalistic evolution is underdetermined by the evidence. That is, one cannot validly conclude, just from evidence in nature, that everything can be explained only and exclusively in terms of natural causes and effects. There is always a background perspective.
How, for example, does one treat the incomplete fossil record? Do we see Tiktaalik (discovered in 2004 in northern Canada, with features combining those of fish and of four-legged animals) as a strong confirmation that land animals evolved out of the sea? Or do we ask why, of all the millions of transitional forms there must have been over the eons, so terribly few have been found? If transitional forms are like rafts for a swimmer across a sea, do we pay more attention to the few rafts or the long water?
But for science, only one perspective is allowed in the debate. As the book said,
In science, explanations must be based on naturally occurring phenomena.
I’ve been thinking about this for a couple of days, and trying to write on it for a long time today, and I’ve just recognized I’m not going to do any better this time than I did in previous postings on this. So I’m re-publishing something I first wrote in December 2005, with some edits and updates. As we’ll see, the NAS’s naturalistic position can only lead to one conclusion, but it’s a position (and therefore a conclusion) that precedes the evidence rather than following from the evidence.
To put it another way: how we interpret the evidences of natural history is inevitably colored by the presuppositions we bring in to the question with us. The NAS position is functionally one of ontological materialism (also known as philosophical materialism, or philosophical naturalism). It does not go so far as saying there is nothing but natural phenomena, but it only admits natural phenomena into discussion. But this is not a position that flows out of science or out of the evidence; it is a position by which one interprets science.
Everybody starts with some opinion on these philosophical and theological issues. The following chart shows how different initial viewpoints will color one’s interpretations. It is not intended to cover all options exhaustively. It’s focused on the major players in the debate. I’ve left out the impersonal pantheistic and polytheistic views of deity, which don’t seem to be involved in the discussion. Pantheists (or panentheists) of the New Age variety typically land in the Neo-Darwinian camp anyway, and other eastern religions do not seem to propose creation stories with any real attempt at credibility. I’m not qualified to speak on their views, at any rate, nor am I qualified to speak on the Muslim form of theism. Panspermia is not included here because it seems to be another version of the ontological materialist view, and this is more about the development of life than its initial origins on earth anyway.
Also, I’m not suggesting that every contributor to this discussion does or should approach it this way. There are Darwin skeptics who haven’t done much metaphysical work, at least not publicly; they’re primarily concerned about empirical (scientific) problems they see in evolutionism. This chart is designed to fit only those who approach it from a particular perspective, and that within limits.
And a final disclaimer: because it is not exhaustive, this chart only works from top to bottom, not in reverse. A philosopher like Antony Flew can accept Intelligent Design and yet have problems with Biblical revelation.

Much of the debate on ID centers on whether it’s credible even to consider the possibility that the development of life has been purposefully guided. That’s where this chart begins. Those who say “no” are ontological materialists/naturalists: they are convinced that nothing at the ground of existence (ontology) has purpose or can act as a guiding agent; all there is, is matter and energy and their interactions. The only option on the table for materialists is neo-Darwinism and/or its intellectual descendants.
Belief in purposeful guidance, on the other hand, is typically tied to belief in a personal God. God’s guidance may conceivably have been entirely contained in “seed” form from the moment of creation, such that God has not intervened since then. This is a generally deistic view, which leads also to something like a neo-Darwinian conclusion, though its assumptions may not be as strictly materialistic as those of many neo-Darwinians.
Among those (including myself) who believe in a personal God who intervenes (the theistic view), some are young-earth creationists who view Genesis 1 as being literally true. Others view Genesis 1 as not being literally true in that sense; most of these hold what I call the figurative/literal view. It’s possible to believe that the Bible is literally true according to the authors’ original intent, and that Moses, the author (under the Spirit’s inspiration) intended the creation story to be viewed in a poetic, figurative sense. There’s no need to discuss that at length; the point is that it’s possible to believe in the divine inspiration of the Bible and yet not believe in a literal 6-day creation.
Thus there are those who believe in a personal God who may have intervened in the development of life since creation, and who do not ascribe to the young-earth view. This group may further divide into two sub-groups, based on their theology or their view of the evidences. The determining question at this stage is whether God’s intervention was hidden or discoverable. Theistic evolution believes God was present and involved in the development of life, but his work was hidden, perhaps even tucked away on a quantum level, so that we will not discover his intervention through empirical means. The final group is that of Intelligent Design theism, those who believe that God’s intervention left traces that scientists can discern today. (Remember where this flow chart begins and how it progresses. It leads to a theistic version of Intelligent Design, but that does not mean that all ID is theistic. ID research that sticks with empirical evidences in nature leads toward intelligence as a conclusion, not toward God. To move to God from ID is to move from science into philosophy and theology. That’s a legitimate move to make, as long as one has recognized the shift in methods and disciplines employed.)
The first octagonal box on the chart points out that neo-Darwinism and theistic evolution are empirically indistinguishable. There is no science that can discern between God being absent or having just hidden his interventions. This contributes to answering whether evolution science and religion are necessarily incompatible. They are not, if this box represents any possible reality. Neither can disprove the other, so neither need view the other as enemy. It also demonstrates that atheistic evolutionists like Dawkins, Dennett, Wilson, etc. have not arrived at their dogmatic atheism through evolutionary science (as they claim) but through other prejudices. Their position is not determined by the evidences.
The second octagonal box asks whether there is any theological need to choose between ID and theistic evolutionism. The question mark is there for a reason. Our friend and former commenter here Mike S. has said there is nothing unbiblical at all in theistic evolution. Young-earth creationists strenuously object. For me, this is a matter that requires more work, yet for now I lean toward a figurative-literal interpretation of Genesis 1, after the hermeneutic suggested by Lee Irons, and an old-earth version of Intelligent Design with God as creator. But it may be that for theists the only way in the end to choose between theistic evolution and ID will be the empirical method.
Interesting, isn’t it, that empirical methods are more determinative for theists than for naturalists! We do not have all our answers pre-determined regardless of evidences; but a strong case could be made that naturalists do.
Related:
Creationism, Intelligent Design, National Academy of Sciences, Worldview