Argument from design
The argument from design, also known as the teleological argument, is an argument for the existence of God that may be summarized as follows: When I see a complex object such as a watch, I know it has been designed: therefore, when I see a complex object such as a tiger, I should infer that it has been designed. This act of comparing two objects and drawing similar conclusions based on similarities (while ignoring important differences) is a prime example of a false analogy.
It is commonplace to associate the argument from design with William Paley, so much so that it is often referred to as "Paley's argument" (or "Paley's watch"). However, the argument is not original with him: by the time he wrote his version, the argument had been advanced by the naturalist and clergyman John Ray, and by William Derham, Fellow of the Royal Society and author of The Artificial Clockmaker; the argument from design had also been discussed critically by David Hume in his Dialogues Concerning Natural Religion.
It is equally an error to charge Paley with plagiarism on this count: he was writing about an opinion so widely known in his time that it was not necessary for him to disclaim originality; and it is not his fault that subsequent generations have tended to give him the credit for the argument. Indeed the argument from design dates back at least as far as Thomas Aquinas.
The argument from design was quickly adopted by creationists as part of their arsenal to toss out during a Gish Gallop but it has found its true home with the intelligent design movement. ID's whole argument is one giant argument from design, its core claims such as irreducible complexity are nothing more than Paley recast in modern genetics.
 A fallacy
The argument from design, used as an argument for the existence of a creator, may have been useful to theists in Paley's day, but it is utterly futile in the hands of modern creationists.
Paley and other theists argued that the appearance of design shows the existence of a designer, addressing his arguments to people who knew of only one cause for the appearance of design, namely a designer.
The creationist, on the other hand, argues that the appearance of design shows the existence of a designer, addressing his arguments to people who know of two possible causes for the appearance of design, namely: the existence of a designer; and evolution by random mutation and natural selection.
Take the particular example given by Paley of the resemblance between the eye and a telescope, for example. It is no use arguing that the eye resembles a telescope and so must have been specially designed for that purpose when talking to someone who understands the evolution of the eye.
To draw a parallel, people used to know about fire as a source of heat and light, but not about nuclear fusion as a cause of these same two effects: and so in those days people quite sensibly based their reasoning on the idea that the Sun was a fire, since it resembled one. We might call this the Argument from Fire. But it would be foolish for someone living today to say: "We know that fire produces heat and light: therefore the Sun is on fire: therefore the Sun is not powered by nuclear fusion."
Not only has biology moved on since Paley's day, but so has design. It is now commonplace amongst engineers, computer scientists, and mathematicians not to design complex structures, but rather to hand the problem over to a computer which simulates the processes of reproduction, mutation, and selection to produce a design fit for a given task. Paley in his day could point to a man-made object such as a telescope, and say "It is complex, so it had a designer". Today, even looking at an object we know to be man-made, we cannot make that inference. To resume the parallel with nuclear fusion, the creationists' use of the Argument from Design is like continuing to use the Argument from Fire even after nuclear fusion has been produced artificially in the laboratory.
 Further problems
Argument from design also fails on another level: it assumes that evidence of design is an objective quality obvious to all viewers. In reality, the ability to discern design is largely a function of familiarity and cultural context. Paley's "watchmaker" analogy presupposes that anyone finding a complex man-made object would immediately conclude that it was designed; however, there have been cases where observers from cultures unfamiliar with such objects have concluded that they were natural. Not to mention the multitude of phenomena we now know are natural, but in the past was explained through intelligent design, such as the Giant's Causeway[wp], the rock upon which the Kyaiktiyo Pagoda[wp] has been built, or the numerous legends explaining how various glacial erratics[wp] ended up in their current positions.
To illustrate: when you walk through the woods and see a watch, you recognize it as designed not because of its complexity or by contrasting it with the surrounding nature, but because you have seen other watches and all of those watches have, to your knowledge, been engineered by people. It is also clearly not safe to judge whether or not an object is designed purely by its complexity. A perfectly smooth perfect sphere is an extremely simple shape. However, if you found a perfectly smooth perfectly spherical wooden ball in the woods, you would recognize it as most likely not having arisen naturally, but rather been carved and sanded into that shape.
The watchmaker analogy, when used in combination with comparison to nature, also fails in that it is self-refuting. If you recognize that a watch is designed because it is more complex than nature, but then you recognize that nature must be designed because it is actually much more complex than a watch, you have a contradiction (is the watch more complex than nature or nature more complex than a watch?). In the case where you don't recognize a watch is complex by comparing it to nature but rather you know that watches are designed, you have an argument that is really nothing more than a set of unjustified assertions (A is complex, A is designed, B is more complex than A, therefore B is designed). How exactly do we define "complexity"? Is "complexity" really a good indicator of something being designed? Is it possible for a simple system to naturally become more "complex" over time?
Humans also tend to assume willful agency is involved in many situations where it is not as part of a survival technique: the extra cost of assuming many non-sentient things in the world might actually be sentient and plotting to harm you can outweigh the cost of death should you incorrectly not make that assumption even once. This manifests today when people are afraid of "bumps in the night", or, more humorously, when people yell at their computers for failure to function as they wish.
The analogy also fails due to being extremely reductive; a watch does not just imply a watchmaker, instead being the culmination of many generations of craftspeople and inventors working in a great many fields, the watch simply being the final link in a chain of uninterrupted, progressively different devices which were adapted to specific demands (sound familiar?). Indeed, if the same logic is used but the device found is scaled up to the point no single human could hope to build it in one lifetime (say, an aircraft carrier) one would have to conclude within the analogy that the machine was the result of divine creation, since clearly no single mortal creator could have made it. This would presumably make it the work of double God.
Most design arguments mangle real technology in a similar way: for example, a modern steel mill could be demonstrated to be the work of a divine being because parts of the mill are made from steel, but making steel requires a steel mill. The creationist argument would be that the mill must have been created by a God who could pull steel from the netherverse, and this would obviously be a much better explanation than there being some earlier and more primitive method of steelmaking that did not require steel parts, because they said so.
 Aesop on the argument from design
Even assuming that the quality of design is objective and obvious to all viewers, a third weakness in the argument from design is the premise that the life-forms that exist have some degree of "perfection" only attainable if they were designed. There is a fable from Aesop illustrating the dubiousness of this notion.
The fable was set at a time when the Greek pantheon were busy about the work of creation. Zeus had made the first man, Poseidon the first bull, and Athena the first house. They could not agree as to which of these creations were the best, so they called in Momus, the god of snark, as a judge. Momus made the following judgments:
- Zeus's man was not good, because his heart had not been placed outside his body to allow others to read his evil intents.
- Poseidon's bull was not good, because its horns had not been set below its eyes so it could see where to strike.
- Athena's house was not good, because it was not a mobile home and could not be moved away from disagreeable neighbors.
Creationists would probably be inclined to do what Zeus did just then: remove Momus's right to judge and kick him out.
In The Blind Watchmaker, Richard Dawkins writes:
“”But of course any God capable of intelligently designing something as complex as DNA/protein replicating machine must have been at least as complex and organized as the machine itself. Far more so if we suppose him additionally capable of such advanced functions as listening to prayers and forgiving sins. To explain the origin of the DNA/protein machine by invoking a supernatural Designer is to explain precisely nothing, for it leaves unexplained the origin of the Designer. You have to say something like "God was always there", and if you allow yourself that kind of lazy way out, you might as well just say "DNA was always there", or "Life was always there", and be done with it.
To say that that the undoubtedly complex Designer doesn't need to be designed is to invalidate the very premise of the argument (it makes use of the fallacy of Special pleading, in other words): that complex things must have designer(s). If one can imagine something complex that doesn't have to have been designed, as proponents of this argument would believe, then who's to say that anything complex needs to have a designer? If taken in tandem with the Kalām argument, we have something complex that didn't need to have been designed because it didn't begin to exist (the Designer). However, since the Kalām argument is invalid, it does nothing to further the case for a Designer, so this argument must be taken on its own--and it doesn't hold up to rigorous analysis.
 Argument from fine tuning
The argument from fine tuning is a variant on the argument from design, bolstered with concepts from modern cosmology, biology and physics as well as mathematical probability. This argument asserts that the conditions able to support life, at least of the kind that exists on Earth, are so specific and narrowly defined, and the odds of such conditions emerging by random chance are so remote, that a deliberate guiding force or creator is a more reasonable explanation.
The narrow range within which life-supporting planets may exist is sometimes called the "Goldilocks Zone" since planets within it are neither "too hot" nor "too cold" to sustain life forms and the conditions they need.
Cosmology without God still begins with something, minimally a vacuum state plus a blueprint for transformation. Since we are alive we can confidently say that the blueprint permits life to exist. But a change of only a few percent in any one of the 80 values called out on that blueprint (such as the delicate ratio between nuclear and electromagnetic force) spells disaster. "Dis Aster" in Latin is literally "Bad Star." Change the blueprint of transformation and the sun fails.
We also know there is not enough mass in the universe to cause the expansion to slow down, stop and reverse to cycle all over again. Indeed the expansion seems to be accelerating, not slowing down, due to a repulsive counterforce to gravity called dark energy that is much weaker than gravity, but which falls off with distance much more slowly, thus making itself felt at very long range. So we've got a one-shot universe, a once-in-an-eternity reality which just coincidentally happens to have a blueprint for transformation which permit suns and planets and life to exist.
The nearest exact twin of the sun is Delta Pavonis, which is 18.6 light-years away from us. To get there, we go east 3.8 light-years, south 6.4 light-years, and down 17.0 light years. Will we find another Earth, complete with life?
- It requires a candidate world roughly at the same distance Earth is from our sun, that is also large enough to retain an atmosphere.
- It requires a gas-giant planet at about 5 times the candidate world's distance from Delta Pavonis to vacuum up deadly inbound comets.
- It requires a giant moon around the candidate world to stabilize the 60 to 80 degree wobble introduced by the comet-sweeping world's gravity, or climate shifts will be too violent.
- It requires a day shorter than 30 hours, so it doesn't get too hot in daytime and cold at nighttime, but longer than 20 hours so Coriolis forces don't make your hurricanes unmanageable.
- It requires a global thermostat to somehow be in place to maintain life as the star Delta Pavonis heats up and reaches its plateau temperature of middle age.
- It requires enough liquid water to form a medium for the birth of life.
- It requires an active geology to build land against erosion, otherwise your highest life-forms will be swamp things.
This can be numerically presented in with constructs such as the Drake Equation.
However, the fine-tuning argument can also be countered due to the sheer size of the universe; with one hundred billion stars in the galaxy, and as many galaxies in the universe, even a minuscule chance of life arising makes it extremely likely that it will occur somewhere. Moreover, no matter how unlikely an event is, once it occurs, the probability of it having happened is 1.
Fine-tuning arguments based on the physical constants are even easier to refute. The delicate balance of, for example, the tri-alpha fusion which created all the carbon in our bodies relies on the temperature and pressure of stars being exactly right for this form of fusion. However, the pressure and temperature of the interior of a star changes depending on whether or not fusion is occurring. Similar links between other physical constants are likely and can explain their apparently delicate balance.
The argument from fine tuning also fails for the following reasons:
- It bifurcates the laws of physics into constants and the equations into which those constants are placed. It asks us to consider what would happen were the constants changed but the equations stayed the same. But what if we permitted the equations to change also? Then we must admit we have no idea. Even if it is clear that the current equations with different constants cannot produce life, completely different equations (and constants) might still be life-producing. We do not know enough about mathematical physics to say, and may well never. This bifurcation of the laws of physics into constants and equations is more likely an artifact of the human mind's attempt to understand the cosmos than a fundamental property of reality itself
- The argument wants us to conclude that it is highely unlikely that a life-producing set of physical constants could be arrived at by chance. But, how do we ascribe probabilities to sets of possible physical constants? Are they all supposed to be equally likely? Or are some more likely than others? And it gets even worse if we reject the bifurcation of the laws of physics into constants and equations -- what is the probability of a particular equation being part of the laws of physics? To speak of probabilities here seems to be just abusing the concept of probability in a situation in which it is meaningless.
Now, if we assume some kind of multiverse theory, then speaking of probabilities of physical constants having certain values, or of certain equations being part of the laws of physics, might have some meaning -- we could look to the distribution of those constant values or laws in different universes across the multiverse to define their probability. But, supporters of the argument from fine-tuning cannot turn to these considerations to make their argument coherent, since if there is such a multiverse then there is no need for the God they are seeking to prove either. It's a Catch-22 for creationists. On the other hand, a multiverse theory could make it significantly 'more' likely this universe was made by pure chance, since there would be infinite other universes, the vast majority of which would not be fit for life due to different constants.
 Lack of perfection
Another argument against design is the lack of perfection which we see in living things. If each one were designed by a perfect god then we would expect each one to be a perfect example of whatever it was. We would expect human vision to be well designed for example. What we would not expect to find would be things showing evidence of evolution such as vestigial organs.
Nevertheless, when we look closely, we find imperfect evolved designs and not perfectly created or ones which show evidence of divine tinkering.
 Backwards causation?
An additional problem with the teleological argument can arise from a reductio ad absurdum concerning things like early human tools. If we come across a spear, which is in its simplest form a rigid shaft with some sort of point at the end, or a hammer, which is in its simplest form some sort of weight, perhaps fixed to a handle, or a flint knife, which is in its simplest form a sharp edge with varying degrees of curvature, the likelihood that the argument inverts the causal chain becomes apparent. Spears and knives broadly resemble the teeth and claws of the animals, predator or prey, that primitive humans would have encountered and struggled with. Hammers are analogous to large fists, accounting for the fact that stone is both more replaceable and less vulnerable than human hands attempting to exert blunt force in pursuit of the same objective. The tendency to incorporate principles like this into the design of our own tools, in recognition of the benefits that large canines or claws or reinforced fists might provide, speaks only to a human capacity for synthetic judgment based on our experience of the world - we don't have large canines or claws, and our fists have serious limitations, but we can emulate these features and gain many of the benefits they provide. It also speaks to the recognition in that synthetic judgment of humans' actually being able to use said tools - that a spear, knife or hammer fits the human hand well only reflects that it was designed by human users for human use. Nature is not so ergonomic - we have to modify sticks and rocks from their natural shapes to be able to use them effectively. The argument from design thus fundamentally imputes to the universe exactly the same processes of synthetic judgment that we make ourselves, making it an egregious sort of anthropomorphism[wp].
 See also
| Articles about intelligent design|
|Main concepts of ID|
|Reductio ad absurdum|