The term teleology refers to explanations that appeal to design and purpose. The teleological argument claims that the appearance of design and purpose in nature implies a designer. Strictly speaking, this is only evidence of “a” designer, not necessarily any specific being. In practice, teleological arguments are often paired with other ideas to imply the existence of a deity, such as the God of the Bible. Teleology is a broad category that includes several narrower ideas, such as fine-tuning, intelligent design, and irreducible complexity. Teleological arguments are suggestions that deliberate choices by God are the most reasonable explanations for certain observations.
Almost every debate over teleology involves defining reasonable evidence of design. This simultaneously demonstrates both the greatest strength and greatest weakness of teleological arguments. In one sense, philosophers have struggled to objectively express the boundaries of “evidence of design.” Teleological arguments are thus framed in terms of likelihood or assumption; this leads to further debates over applying mathematical probability. On the other hand, human experience routinely distinguishes between intent and accident; attempts to reject teleological arguments often run counter to the principles used in virtually all other circumstances.
Teleological arguments broadly suggest that some observations are more reasonably explained as resulting from purpose and design, rather than random accidents. A patch of sand shaped like the letter C would typically be interpreted as random. A perfect circle in the sand would raise questions. Ten perfect circles, arranged to look like a human face, would cause observers to naturally assume a prior intentional action. A large furrow carrying water from one puddle to another will be interpreted differently than will a thin, straight ditch bringing river water directly to a farmer’s field.
Arguments for design are more intuitive than objective, so they can be difficult to assess. In strict logical terms, many events we interpret as intentional could be the result of something random. Improbability does not necessarily imply intent. At the same time, and for the same reason, teleological arguments derive great strength from the extreme odds involved. Just because something is possibly random does not mean it’s reasonable to assume it really was accidental.
As an example, consider the card game stud poker. In this game, players are dealt seven cards, and they select the best five-card combination. Cards are randomly dealt from a deck of fifty-two cards, split into four suits—hearts, clubs, diamonds, and spades—of thirteen cards each. The ultimate hand in this game is the royal flush, which includes the top five cards of a single suit. The odds of obtaining this hand from a fair deck are about 1 in 31,000, or 1:3.1x104.
If a player were to obtain a royal flush, other players would be disappointed, but likely to accept the outcome as possible. If the same player obtained a second royal flush in the next hand, opponents would naturally suspect something underhanded. It is possible a person could get two consecutive royal flushes. Yet the odds of this happening are about 1 in 957 million, or 1:9.57x108.
Mathematically, it’s even possible to be dealt five royal flushes in a row, albeit at odds of 1 in 28 sextillion, or 1:2.83x1022. However, none of the other players at the table would accept randomness as a valid explanation. The likelihood of that happening by pure chance is so vanishingly small that it is by far more reasonable to assume cheating. At the very least, the other players would demand further investigation.
Attempting to refute teleological arguments for God’s existence often results in a similar quandary. Some arrangements of nature are so improbable, yet so necessary, that they demand interpretation as the result of “fine-tuning” by an intelligent mind. Dismissing appearance of design by appealing to blind luck opens the door to rejecting almost all scientific knowledge; ignoring the implications of probability makes experimental observations meaningless.
Sometimes, mathematical probability cannot be objectively assigned. Even then, commonsense principles lend weight to teleological arguments. Ratios and odds aren’t involved in concluding that “Watch Out for Sharks” carved in sand on the beach was written on purpose. Nor does a person need a calculator to decide whether an arched stone bridge across a river was an accident. Some patterns and arrangements are universally associated with intentional action. Yet these same principles are often ignored when attempting to refute teleological arguments for God. For instance, those who presume the outrageous sophistication of DNA—an actual “code”—formed without any greater purpose are ignoring the logical implications of the existence of that code.
Another aspect of teleological arguments involves situations that are not only improbable, but seemingly impossible. In the card game example above, it is theoretically possible for five random hands dealt from fair decks to result in five royal flushes. The components are there. But if a player were dealt two of the same card, such as receiving two kings of diamonds, it would be proof that either the deck or the dealer is not fair. This is the case with issues such as abiogenesis—life arising from non-life—which all scientific observations have demonstrated to be impossible.
If something cannot happen according to certain assumptions, but it does happen, then the assumptions are wrong. Teleological arguments leverage the apparent impossibility of certain things happening naturally. The more reasonable assumption is that something—or Someone—is acting outside of the established rules of the system.
A common term when debating teleological arguments is gaps. Critics frequently miscast teleological explanations as, “We don’t know how this happened, so God did it.” This is referred to as the “god of the gaps” error. In some cases, this criticism has merit. Reaching the end of our understanding does not necessarily imply the next causal step is “direct intervention of a deity.” Framed in that way, arguments in favor of God are logically weak. At the same time, merely pointing out the appearance of design and intent is not a “gaps” error. If something appears to be deliberate, considering that fact is not an argument from ignorance: it’s a positive use of all information.
Those claiming “god of the gaps” often confuse mechanism for agency. Explaining how something happened does not logically explain away intent. Arguments for design only require that certain situations strongly correlate with intent or purpose. Teleology does not require disproof of all mechanisms leading to the end state. An automobile’s steering involves multiple steps between the movement of the tires and the intent of the driver. Pointing out the existence of power steering, an electronic control unit, or the entire series of machinery would not excuse a driver who wrecks the car. Learning “how” something happens does not mean there is no “who” behind it.
It is also common to respond to teleological arguments with an “atheism of the gaps” approach. This simply says, “Blind randomness cannot explain this yet, but we should assume we will eventually.” This is an especially common tactic when dealing in issues such as abiogenesis, where observations move beyond improbability into what seems like impossibility.
Closely related are claims of “poor design,” where a perceived flaw is held up as proof that the designer is inferior. Logically, this does not disprove teleology—intent is intent, even if it’s fallible. Such arguments are also typically shallow. Engineers often make valuable design choices that end users won’t intuitively understand. A farm worker might complain that almost every time his auger breaks, it’s because a small, relatively weak pin in the shaft is breaking. Since he’s replaced that pin several times, he might think it should be made stronger. But what the worker dismisses as “poor design” is a deliberate choice by the designer. A shear pin is easily replaced; it is intended to break before excess stress destroys more expensive parts of the auger. What the farm worker considers a flaw is a feature saving him from even worse complications. Complaints about vestigial organs and misunderstood design of the human body fit into this category of error.
Teleological arguments are useful, though not logically absolute. Viewed in the context of normal human observation, they take on great potency. In fact, the lengths required for some critics to dismiss these arguments speak to their value. Critics of religion frequently concede that biology and nature give every appearance of being designed. The only justification given for concluding otherwise is preference—that is, because the existence of God or any divine influence must be refuted at all costs. This comes across very much like a poker player saying, “It strongly appears that I’m cheating, so please be sure to assume I am not.” For those lacking such bias, probability and common sense lend weight to the value of teleological arguments.