My children are learning to tell jokes and riddles. Two-year-old Samantha enjoys repeating jokes, but she does not understand them. Five-year-old Nate comprehends some jokes, but his own riddles do not work. Seven-year-old Alison has got it down. "Why do cows wear bells around their necks?" she asks. Before I can respond, she blurts out, "Because their horns don’t work!" Alison understands that riddles are based on puns and double-meanings. A riddle’s punch-line depends on a switch to a different sense of meaning, the funniest of which are obviously absurd.

I remember my first attempt at making up a riddle: "Why do goats have horns?" Answer: "Because God made them that way!" Of course, this is not particularly funny. Instead of switching meanings of the word "horn" (e.g., "Because kids always drive crazy on the troll bridge!"), my punch-line played off different meanings of the word "why."

Obviously, there are several ways of interpreting and answering this question: "Why do goats have horns?" Is it because (a) nutrients, cells, and hormones interact in appropriate measure during goat ontogeny? (b) goats inherit genes that specify horn development? (c) horns assist goats (or assisted goat ancestors) in surviving and obtaining mates? (d) horned goats are part of God’s intended expression of his creativity? or (e) God made them that way?

Here, the riddle gets serious. Instead of shifting to absurd meanings (with their attending humor), these "punch-lines" remain sensible. More significantly, they can seem conflicting, without a navigable connection between them by which to "translate" one into the other. Of course, the conflict is not in the underlying reality, but in the different modes of description used to communicate alternative levels of meaning.

It appears that profound riddles are the unavoidable consequence of all human endeavors to observe, interpret, and describe reality and truth. When I told my riddle at age five, I could not appreciate how important this "Lesson of Riddles" would become in my life. Today, as both a Christian and an evolutionary biologist, I am glad for the opportunities I have had to wrestle very consciously with the "Lesson of Riddles," to mature in faith by exercising an appreciation of the alternative forms of meaning inherent in all human understanding. Indeed, I find the concept to be an essential part of what it means to have a faith at all.

Certainly, my upbringing influenced how I came to appreciate the "Lesson of Riddles." My Midwestern American family heritage is bound more by a strong thread of genuine Christian faith than by any ethnic or vocational tie. I cannot remember a time when faith in Christ and involvement in church were not the defining themes of my family’s activities; nor can I remember a time when I did not believe in Jesus as my Savior and Lord. My upbringing might have remained culturally myopic and theologically rigid, except that my family moved to Iran in 1972, where my parents began work as self-supporting missionaries. Those seven years in Iran broadened my cultural perspective, my Christian identity (via friendships with missionary families from other Christian traditions), and my sense of history (via visits to ancient archeological sites).

Then there were the summers spent stateside at the National Music Camp in Interlochen, Michigan. While my parents worked on staff and my brother and sister were campers, I spent all my time fishing, catching snakes and turtles, collecting butterflies, exploring creek tributaries, and searching for Indian arrowheads and Petosky fossils. Undoubtedly, these were the experiences that sparked my interest in biology.

When I was twelve, my family left Iran following the 1979 revolution. I had a rough year adjusting to American schools and the narrow world view of my peers. When my father eventually obtained a job as music pastor (and later missions pastor) at Elmbrook Church in Waukesha, Wisconsin, it meant a new start for me. I quickly became absorbed in the church youth group. I remained interested in missions, spending one summer in the Philippines and another in Kenya. I also attended Urbana missions conferences in 1984 and 1987.

Although I was voted "most conservative" of my high school graduating class of 1985, I considered myself intellectually liberal. I held strongly to my Christian faith and my commitment to missions (with its attending theology of salvation only through Christ), but I enjoyed listening to diverse musical styles, reading world literature, discussing philosophy, considering alternatives to the political right, and laughing at parodies of American Christian pop culture. In other words, I was always keenly aware of the difference between reality and current human expressions of that reality.

When I started at the University of Wisconsin, my interest in biology rekindled. I soon became especially interested in the biology of plants, a group of organisms I had hardly taken notice of before. While still a sophomore, I took an upper-level ecology class and swallowed up every detail. As a junior, I especially enjoyed plant taxonomy and plant biogeography. At this point, I did not need an evolution course to convince me that all I had observed and had learned about biodiversity, biogeography, ecology, genetics, and geology was interconnected by a wondrously real, functional, and formative natural history. I was invigorated by the challenges of inferring patterns of biological diversification (speciation), and I was humbled to contemplate that God had recorded in his creation visible traces of his work by which I might appreciate more fully the overwhelming extent of it.

(what I have introduced here as the "Lesson of Riddles"). The principle states that, because human knowledge is never complete, alternative modes of description (i.e., answers to the same question) may often be formally incompatible even while both are valid (i.e., accurate) perceptions of the same object (i.e., reality).

I first learned the "Lesson of Riddles" in a science class because complementarity emerges within the practice of natural science itself. For example, in biology the concepts of genotype and phenotype comprise alternative modes of description with respect to inheritance. We have known for nearly a century that genotype and phenotype are thoroughly connected in reality; yet our knowledge at present remains insufficient to draw a complete straight-lined (i.e., deterministic) relationship between them (except in the most simplistic cases). I have come to appreciate the fact that fruitful investigation and discovery in natural sciences has continued despite (indeed, because of) such "incompatibilities" among modes of description.

The "Lesson of Riddles" also applies in Christian theology, that science by which we observe and interpret Scripture (God’s revelation of truth) and describe our understanding in the form of doctrines. For example, in some very important sense, all Christians affirm that God is sovereign, that humans have free will (i.e., responsibility for their actions), and that God is not the author of sin. Nevertheless, we are unable to fully comprehend and completely explain how these basic doctrines can coexist. Although different systems of doctrine provide helpful ways to think about the whole, no one of them does complete justice to the depth of these difficulties. Thus, while theologians strive to work out these complexities as a noble pursuit, the individual follower of Christ (myself included) proceeds in confident faith despite the tensions that remain.

Of course, the more specific concern of Christians in science is how the "Lesson of Riddles" applies to the relationship between natural science and theology. Actually, I believe this concern belongs to every Christian in every life experience. This is because we are both physical and spiritual in being. Every human experience has both physical and spiritual implications, and these implications comprise alternative modes of describing the experience. For example, when we are sick, we pray for God’s healing and simultaneously seek medical attention. If healing comes, we thank God for answering our prayers even while we acknowledge the use of medicine in materially effecting the cure. If healing does not come, we understand that current medical treatments are not one hundred percent effective, but we also affirm God’s sovereignty over our condition. Even in those cases where healing comes without an attending physical explanation, we are wise not to condition our thanks to God on there being no physical basis in fact. In every experience, we acknowledge the validity of both physical explanations (based on natural science) and spiritual explanations (based on Christian theology), though the two accompanying languages are very different.

In so many words, Lewis acknowledges that there is little about the manifestation of spiritual experiences that cannot be explained by natural processes. Consequently, the philosophical naturalist will observe little in a supposedly spiritual event to compel him to abandon his conclusion that the physical realm is "all there is." Lewis’s essay is addressed to Christians, however, and as such it expresses a top-down or presuppositional approach to understanding Christian experience rather than a bottom-up or evidentialist apologetic aimed at convincing skeptics. ("Transposition" refers to the top-down expression of spiritual truth into the physical medium, which is thereby sanctified and "lifted" into greater meaning).

In several important respects, Lewis’s "doctrine of Transposition" rings true with me personally. It promotes a godly attitude of bringing everything (even our most mundane and "natural" acts) under the Lordship of Christ. It also represents a healthy respect for the "Lesson of Riddles." Indeed, Lewis wrestled with the "problem" presented by alternative spiritual and physical modes of description; he did not attempt to invalidate one mode with language from the other. I conclude that we should not—and in most circumstances, in fact, do not— require that all conflicts among our alternative modes of description be resolved fully and clearly as a prerequisite to our acceptance of a particular form of understanding reality. Knowing the physical basis of a disease and its cure does not, in itself, invalidate the very immediate work of a sovereign God in all aspects of those same events; or visa versa. And just as this principle applies in regard to the natural realm in terms of its current function (physics, chemistry, physiology, ecology, inheritance), it also applies to the natural realm in terms of its past function and formative history (cosmology, chemical and biological evolution, etc.). I am convinced by the manifold scientific evidence that the earth has enjoyed a long evolutionary history in which continents have separated and collided, mountains and seas have appeared and disappeared, glaciers have advanced and receded, species of living organisms have multiplied from common ancestors, and a rich diversity of life forms has evolved to fill the whole of it.

I am left to wrestle with certain difficulties relating to the biblical account of creation, and I do wrestle with them rather than ignore them. However, I cannot dismiss the compelling scientific evidence for evolution solely to avoid conflict with a traditional interpretation of the creation account. And, in the end, I have found that the theological difficulties are no more difficult from my scientific position than from a young-earth or non-evolutionary one.

Finally, the "Lesson of Riddles" advises me against carelessly co-opting the language of one descriptive mode into another. Indeed, to do so becomes an absurdity, placing one squarely into the realm of comedy once again. I remember discussing human evolution and descent-with-modification with a pastor friend. He disagreed with my understanding of the evidence on the basis that, because humans are the pinnacle of creation, humans are not descended but ascended!

As Lewis points out in his essay, there is no one-to-one correspondence between alternative modes of description: no word-for-word translation and no straight-line connection. That evolution involves random mutations and chance events does not disturb my theology of God as sovereign Creator and Sustainer because I do not attempt to make a word-for-word translation of the languages used in these two modes of description. Likewise, I do not attempt to relate the fact that natural selection depends on "survival of the fittest" with God’s concern for the weak and fatherless by a simplistic one-to-one correspondence. Even the description of evolution as occurring "without plan or purpose" has its appropriate (valid) sense of meaning, namely that evolution occurs without a plan or purpose of its own; species do not, indeed cannot, anticipate where to go evolutionarily.

Not too long ago, I suffered through a sermon based on Matt. 16:1–4.

In expounding this passage, the preacher missed its central point by failing to appreciate the "Lesson of Riddles." He spent the better half of his sermon first disparaging the godlessness of evolutionary theory (as unable to interpret the sign of the times) and then praising recent efforts of intelligent design theorists (as the right way to interpret the signs). But Jesus was not pitting two scientific theories against one another; nor was he suggesting that scientific description of the weather was invalid. Rather, he was chastising his hearers for not using their cognitive abilities (as they do correctly in the way of natural processes) also to contemplate God’s unique revelation of truth in Scripture and human history. In effect, he was saying, "You know how to think about natural processes and do good science, but there is more than one mode of describing what you see and hear; you need to understand from a spiritual perspective just as you already do from a physical one."

Indeed, reality is more than physical and chemical, but it is not less than physical and chemical, at least not as long as there is a creation. To be human means more than to function chemically, physiologically, and ecologically and to be the product of biological evolution (a formative history), but it is not less than these things. The natural realm (the domain of natural science) is not "all there is," but it exists. It has orderly laws by which it may be examined from top to bottom and from beginning to end. Will scientists (Christians or non-Christians) discover complexities within the natural order that cannot be explained legitimately by physical modes of description? Are there components of the time-bound creation where physical reality ends and only spiritual reality remains? Perhaps, but everything that I have ever experienced suggests that I should not count on this to be so.

Riddles remain as mind-benders to spur me on in scientific research and as spirit-molders to press me into stronger faith. At times it seems as if God is intent on frustrating me, but I believe his purpose is to keep me trusting in him at every turn.