Does life look designed, or does it just look that way?

1. 1

   The watch on the heath

   In 1802 an English clergyman named William Paley published Natural Theology, and its first paragraph became the most famous argument in the history of the design debate. Here it is, in his own words, because it deserves the room:

   “In crossing a heath, suppose I pitched my foot against a stone, and were asked how the stone came to be there, I might possibly answer, that, for any thing I knew to the contrary, it had lain there for ever: nor would it perhaps be very easy to show the absurdity of this answer. But suppose I had found a watch upon the ground, and it should be inquired how the watch happened to be in that place, I should hardly think of the answer which I had before given, that, for any thing I knew, the watch might have always been there.”

   Paley's point is the difference between the two objects. The stone raises no question. The watch does — and it raises the question because of what you find when you open it: parts shaped for each other, arranged so that motion in one produces motion in the next, the whole assembly pointed at an outcome none of the parts has on its own.

   From that he draws the conclusion the argument is named for: “there must have existed, at some time, and at some place or other, an artificer or artificers who formed it for the purpose which we find it actually to answer; who comprehended its construction, and designed its use.”

   Then he turns to the eye. Paley knew optics, and he walks through the eye as an instrument — the lens that refracts, the humors of different density that correct for the way light bends, the adjustment for distance, the fact that a fish's eye is built differently in exactly the way you would build it differently for seeing through water. Every step is an argument that this is not a lump of tissue that happens to work. It is a solution to a problem, and solutions imply someone who had the problem in mind.

   For fifty years this was close to unanswerable in English-speaking thought. Darwin read it at Cambridge and later said he had been delighted by it.

   • “The heavens declare the glory of God; the skies proclaim the work of His hands.”

     Ps 19:1 — The heavens declare the glory of God; And the firmament showeth his handiwork.→

   • “For since the creation of the world God’s invisible qualities, His eternal power and divine nature, have been clearly seen, being understood from His workmanship, so that men are without excuse.”

     Rom 1:20 — For the invisible things of him since the creation of the world are clearly seen, being perceived through the things that are made, even his everlasting power and divinity; that they may be without excuse→

2. 2

   The objection that came first

   The popular telling of this story has Paley making the argument and Darwin knocking it down half a century later. That telling has a hole in it: the sharpest philosophical objections to the design argument were published in 1779, twenty-three years before Paley wrote, in David Hume's Dialogues Concerning Natural Religion.

   Hume was not answering Paley. Paley was, in a sense, answering Hume — and a fair reader has to decide whether he succeeded. Hume's Dialogues are public domain, so his case can be printed here rather than described.

   The objection comes in three prongs, and they are independent: if one fails the others still stand.

   First, the experience problem. Every inference from an effect to a cause rests on having seen that pairing before. We infer a watchmaker from a watch because we have seen watches made, thousands of times, and know what making one involves. Nobody has ever observed a universe being made, or a species being made. There is no repeated pairing to generalize from — we are being asked to reason about a class of event with exactly one member, and no observed cause.

   Second, the analogy problem. The argument depends on a universe being relevantly like a machine, and Hume's Philo pushes back hard on the resemblance: “But wherever you depart, in the least, from the similarity of the cases, you diminish proportionably the evidence; and may at last bring it to a very weak analogy, which is confessedly liable to error and uncertainty.” A universe grows, reproduces, decays, and generates order from the inside. So does a vegetable, and so does an animal. Why is a clock the right comparison rather than a plant? Choose the plant and the argument produces a world that generates itself.

   Third — and this is the prong apologists most often skip — even a completely successful design inference does not deliver the God anyone actually worships. Hume: “A great number of men join in building a house or ship, in rearing a city, in framing a commonwealth: why may not several deities combine in contriving and framing a world?” And, on quality: “This world, for aught he knows, is very faulty and imperfect, compared to a superior standard; and was only the first rude essay of some infant deity, who afterwards abandoned it, ashamed of his lame performance.”

   That third prong is the one this site takes most seriously, and it is not answered later on this page. Design arguments, if they work, get you to a designer. They do not get you to one designer, or a good one, or a present one, or the God of Israel. Anyone who tells you otherwise has quietly added premises they did not show you.

3. 3

   Darwin's answer, in Darwin's words

   In 1859 Darwin proposed a mechanism that could, in principle, produce apparent design without a designer: heritable variation, differential survival, and enough time. Small differences accumulate; the ones that help their bearers leave more descendants; structures build up step by tiny step, each step useful on its own.

   The key word is cumulative. Nobody claims an eye assembled itself by chance in one go — that would be absurd, and the people arguing for evolution say so more loudly than anyone. The claim is that chance supplies variation and selection supplies direction, and that direction is not random.

   Darwin knew exactly what this did to Paley, and he wrote it down in his Autobiography with no gloating and no hedge: the old argument of design in nature, as given by Paley, which formerly seemed to him so conclusive, “fails, now that the law of natural selection has been discovered.”

   It is worth pausing on how much that concedes and how much it doesn't. Darwin is not saying the appearance of design was imaginary; he had spent his life documenting it. He is saying there is now a candidate explanation that does not require an artificer. Whether the candidate is adequate to everything it is asked to explain is where the modern argument lives.

4. 4

   The modern form: irreducible complexity

   In 1996 a Lehigh University biochemist named Michael Behe published Darwin's Black Box and reframed Paley's argument for the age of molecular biology. Paley opened a watch; Behe opened a cell.

   His central concept must be printed exactly as he defined it, because paraphrases of it are usually strawmen. Behe's definition, Darwin's Black Box (1996), p. 39 — an irreducibly complex system is:

   “a single system composed of several well-matched, interacting parts that contribute to the basic function, wherein the removal of any one of the parts causes the system to effectively cease functioning.”

   The argument that follows is straightforward. Natural selection can only preserve what already works. If a system does not function at all until every one of its parts is present, then the incomplete versions along the way conferred no advantage, and selection had nothing to preserve. Such a system, Behe argues, would have to arrive as a unit.

   His examples are the ones the debate has revolved around ever since: the bacterial flagellum, a rotary motor with a drive shaft, bushings, and a whip-like propeller; the blood-clotting cascade, a chain of enzymes that has to fire in order and stop on time; cilia, the beating hairs that move fluid across tissue; and the adaptive immune system.

   One thing has to be said plainly here, because getting it wrong would misrepresent a man this site cites. Michael Behe is not a young-earth creationist. He accepts an ancient earth and, in many cases, common descent — including common ancestry for humans. His claim is narrower than the way it is usually deployed: not that evolution did not happen, but that unguided mechanisms are insufficient to account for certain molecular machines. MannaFest's own position on origins is stated elsewhere and is not Behe's. Citing a man accurately matters more than recruiting him.

   • “I praise You, for I am fearfully and wonderfully made. Marvelous are Your works, and I know this very well.”

     Ps 139:14 — I will give thanks unto thee; for I am fearfully and wonderfully made: Wonderful are thy works; And that my soul knoweth right well.→

5. 5

   The rebuttals, at the same size

   Behe's argument drew serious scientific replies, and they get the same space here that he got. Anyone who reads only the first half of this page has read half of it.

   The first reply is about the flagellum specifically. Some bacteria possess a Type III secretion system — a molecular syringe used to inject proteins into host cells. It shares roughly ten structural elements with the flagellar basal body, and it works while lacking on the order of forty of the proteins the flagellum needs. That matters directly to the definition quoted above: a subset of the flagellum's parts turns out to have a function of its own. Behe has responded that the secretion system may be a degenerate descendant of the flagellum rather than a precursor to it, and the direction of derivation is genuinely argued among specialists. But the specific claim that no subset can do anything is the claim that took the damage.

   The second reply is the general one, and it is older than the argument it answers: co-option, or exaptation. Structures are routinely recruited for jobs they did not originally do, which means the parts of a system need not have been useless before the system existed — they were useful for something else. The textbook case is not molecular at all and can be traced bone by bone in the fossil record: the mammalian middle ear, whose tiny hearing bones derive from bones that were part of the reptilian jaw joint. The same parts, doing a different job, then reshaped for the new one. Feathers, likewise, preceded flight.

   Kenneth Miller — a cell biologist at Brown University, and a practicing Catholic, which is worth knowing because this is not a fight between science and faith — laid out both replies for general readers in Finding Darwin's God (1999) and argued them in person against Behe.

   The third reply came from a federal courtroom, and because a US court opinion is a public record, it can be quoted here in full rather than characterized. In Kitzmiller v. Dover Area School District (M.D. Pa., 2005), Judge John E. Jones III heard six weeks of testimony, including Behe's own on the stand. The opinion found that Behe's irreducible-complexity claim “has been refuted in peer-reviewed research papers and has been rejected by the scientific community at large,” and that irreducible complexity “does not make testable the argument for ID.”

   Be precise about what that does and does not settle. A court decides a legal question — here, whether teaching intelligent design in a public school science class violated the Establishment Clause — and courts are not arbiters of biology. A different judge does not make a bad argument good. But the ruling is not merely legal either: it rests on an extensive evidentiary record, cross-examination of the proposal's leading advocate, and a finding about testability that no subsequent research program has overturned. Christians are entitled to dislike the verdict. They are not entitled to pretend the trial did not include the evidence.

6. 6

   The other modern argument: information

   A second line of argument moved the question from machines to messages. DNA does not merely have structure; it carries a sequence, and the sequence is read. Three-letter groups specify amino acids by a convention that is nearly universal across life, and the same molecule is copied, proofread, and repaired. That is the vocabulary of code, and codes in every other context we know of come from minds.

   Stephen Meyer developed this at book length in Signature in the Cell (2009), cited here and not quoted beyond a phrase. His argument is an inference to the best explanation applied to the origin of the first self-replicating system: chance is inadequate for sequences of that specificity, necessity produces repetition rather than specificity, and natural selection cannot be invoked because selection requires replication, which is the very thing being explained.

   The standard objection is precise and should be stated precisely: the word information is doing more than one job in that argument. Information theory in the technical sense measures the improbability of a sequence and is indifferent to meaning — a random string has high information in that sense. What the argument needs is meaningful, functional, purpose-carrying information, which is the everyday sense that does imply a mind. Slide between the two senses and the argument looks stronger than it is. Critics say the slide is doing the work; defenders say the functional sense is what they meant throughout and that it is measurable in principle.

   Where the honest reader lands: the origin of the first replicating system is a genuinely unsolved problem, and everybody working on it says so. Unsolved is not the same as unsolvable, and it is not the same as solved in our favor. It is a place where the argument for design is live, and where the argument from a gap is easiest to abuse.

Each objection below is stated the way the people who hold it state it. If you hold one of these and think it is put unfairly here, that is a failure on our part — tell us.