Steven Dutch
The Case Against the Argument From Design
We cannot validly reason from earthly parallels to the Universe as a whole.
Since the creation of the universe was a unique event, we cannot say anything about it.
The order in nature could equally well result from the intrinsic properties of matter itself.
The existence of pain and suffering cast serious doubt on the existence of a benevolent Intelligence.
[I] Critique
The nature of science has changed dramatically since Hume's day, and the changes illustrate some holes in Philo's reasoning that probably would not have been apparent to Hume or anyone else at the time.
In Hume's day, the only rigorously known scientific laws were gravitation and Newton's laws of motion. The fact that these had successfully explained the motions of the planets had profoundly impressed all of society. Also, Newton had successfully explained why Kepler's empirical laws of planetary motion worked, and even made a correction to them. Still, nobody in Hume's day suspected the extent to which it would be possible to explain laws of nature in terms of still higher laws. Hume's trio was restricted to finding order in nature solely in the complex phenomena of the natural world, something that might not be the case today.
In Hume's day the stars were considered so inconceivably remote that it seemed impossible ever to have any real knowledge of them. Double stars, where one star orbits another, would be the first direct demonstration that gravitation applied among the stars. Spectroscopy, with its incredible power to analyze the physics and chemistry of the stars, was a century in the future. Quantum mechanics, which successfully explains what spectroscopy observes, was three quarters of a century beyond that. So we can forgive Hume for not envisioning how deeply we would be able to test the hypothesis that the laws of nature are the same everywhere. Nevertheless, Philo's argument that we cannot reason from earthly examples to the universe as a whole is flatly, definitively, wrong.
Mid-18th century Edinburgh was home to one of those brilliant collections of minds that appear from time to time, called the Scottish Enlightenment. Hume probably knew James Watt. A few years before the Dialogue was first published, Watt realized that existing steam engines were inefficient because they alternately heated and cooled the same vessel. He envisioned a completely new design in which spent steam was exhausted to a separate vessel to be condensed. His invention would launch the Industrial Revolution. So what? You envision a new way of doing things and build it. This is how technology works, right? Not in Hume's day. Hume could have Philo argue (Part VIII) "In all instances we have ever seen, ideas are copied from real objects...You reverse this order and give thought the precedence." The idea of conceiving something totally new and making it happen, the essence of modern technology, is completely opposite to the mental processes of Hume's time. We can forgive Hume for not foreseeing the extent to which abstract thought could precede the creation of objects, but again Philo's argument is flatly, definitively, wrong.
[II] A Sample With N = 1
"When two species of objects have always been observed to be conjoined together, I can infer, by custom, the existence of one wherever I see the existence of the other. And this I call an argument from experience. But how this argument can have place, where the objects ... are single, individual, without parallel, or specific resemblance, may be difficult to explain..... To ascertain this reasoning, it were requisite that we had experience of the origin of worlds..."
Here's another case where Hume utterly (and nobody can blame him) failed to foresee the growth of science. He would doubtless be astonished at how much we can infer about the origin of the universe.
But let's look at the validity of the argument even in Hume's day. The French mathematician Laplace would publish the first speculation on the origin of the solar system shortly after Hume's death. It simply is not true that we cannot reason about a unique event.
[III] Hume's Central Circularity
The issue to be decided is whether the order in nature is the result of intelligent design. If it is, then the properties of matter (the color, luster and density of gold, for example) are also the result of intelligent design. Postulating a dichotomy between intelligent design and the properties of matter therefore amounts to postulating a priori that there is no design in nature. Hume (and all who follow him) essentially follow a grand circularity:
Matter and the laws of nature are defined a priori to be separate from any intelligent design.
Order in nature is shown to be the result of the laws of nature and the properties of matter
Therefore order in nature is not the result of intelligent design
Nowhere is the circularity more blatant than Jacques Monod's Chance and Necessity. Monod starts by asking what criteria one would use for deciding something was intelligently designed and defines two criteria: repetition and geometric regularity. But, he hastens to add, these criteria apply only at the microscopic level. The distinction is entirely ad hoc because, if we applied it at the microscopic level, the Argument from Design would follow automatically. In any case, the distinction is nonsense, since macroscopic non-biological structures like crystals, cloud patterns and orbital resonances in the Solar System display repetition and geometric regularity, and microscopic structures like computer chips are of clearly intelligent origin (the bug in the first Pentium chip notwithstanding).
[IV] Lacuna Matata (Don't Sweat the Holes)
There's probably no greater lacuna in Hume's reasoning than in Part IX. Demea asks why there should be something rather than nothing, and why the universe we know instead of something else. By definition there can be no external cause, hence the only explanation is a logically necessary Being who "carries the Reason of his existence in himself, and who cannot be supposed not to exist without an express contradiction." (I run into people who quite literally cannot conceive of their religious beliefs being wrong, for whom the very concept of the Koran being wrong is a logical contradiction.)
Hume puts the reply in the mouth of Cleanthes, who says it only to forestall Philo. Hume presumably assigns this role to Cleanthes to spare Philo the burden of attacking every religious doctrine and thereby alienating readers, but it's quite definite here that Cleanthes is voicing Hume's own convictions. He says:
Nothing is demonstrable, unless the contrary implies a contradiction. Nothing, that is distinctly conceivable, implies a contradiction. Whatever we conceive as existent, we can also conceive as non-existent. There is no Being, therefore, whose non-existence implies a contradiction. Consequently there is no Being, whose existence is demonstrable.
This is essentially disproof by outright denial. We can conceive of God as non-existent, hence God cannot be logically necessary. The only thing missing is any proof that the conception of God as non-existent is valid even in principle. Cleanthes shortly cites the idea that 2 + 2 = 5 as an example of a logical contradiction. By the logic above, if I say I can conceive of 2 + 2 = 5 not being a contradiction, that makes it non-contradictory, since I can conceive of the contradiction being non-existent.
Cleanthes (Hume) goes on to say that the universe might well contain hidden attributes that would make its non-existence seem as contradictory as the non-existence of God. Considering how hard Hume hammers elsewhere at the unproven nature of religious conjectures and their ad hoc nature, postulating wholly unknown properties for the universe is a nice case of the pot calling the kettle black.
But there's more. Cleanthes (Hume) says the only argument that persuades him the universe (rather than God) is not the necessarily existent entity is the fact that we can validly conceive of it being different. "But it seems a great partiality not to perceive, that the same argument extends equally to the Deity." Let this soak in. The entire thrust of Hume's arguments up till now, mostly as voiced by Philo, have been that we cannot reason from our knowledge of design on earth to design in the universe. Now Hume uses Cleanthes to assert that because we can conceive of matter being different than it is, we are justified in conceiving of God being different than he is. If there is something about God that makes him logically necessary and immutable, it must be attributes we do not know, and we have no way of knowing whether the same qualities might not reside in nature. We're back to proof by postulating unknown hypothetical properties of the universe.
Hume essentially gets away with using mutually contradictory arguments by putting them in the mouths of two different characters, but nothing could be clearer than that Cleanthes, in this section, is relating Hume's ideas exactly.
[V] A Truly Weird Argument
In Part VII, Philo describes that in Indian mythology, the universe was spun by a great spider, and goes on to say:
And were there a planet wholly inhabited by spiders (which is very possible) this inference would there appear as natural and irrefragible as that which in our planet ascribes the origin of all things to design and intelligence, as explained by Cleanthes.
This argument is so wonderfully naive and blatantly anthropomorphic one hardly knows where to begin. A good starting point is to say duh..., any primitive intelligent species is likely to picture God as a larger version of itself. Spiders on this planet don't, as far as we know, have any conception of God so we don't need to worry about what they think, if indeed they have any more cognition than a personal computer.
So Philo's hypothetical spider planet would have to be inhabited by intelligent spiders. Just as human thinkers in Hume's day had long since concluded that it was mere imagination to picture God in human form, by the time Philo's spiders reached a similar level of development, the more intelligent ones should have gotten over their primitive arachnomorphism and reached the same conclusion. No doubt their artists would still picture God as a spider, but they would realize that was an image, not necessarily reality. (The only people on our planet who really seem to believe God is an old man with a long white beard are cartoonists and atheists.)
Spider webs, of course, are a matter of biology rather than conscious effort, but a race of spiders that remained at that level would be unlikely to have enough consciousness to speculate about God. Who knows what sorts of webs intelligent spiders might spin? (Just imagine the webs a spider mathematician might weave!) And even if we postulate a race of spiders that did nothing but spin webs and engage in philosophy while waiting for hapless flies, this argument still embodies the fundamental circularity of assuming that complexity in nature (spinnerets and spider webs in this case) are not the result of design, then using their "naturalness" to "prove" that the complexity is not the result of design.
[VI] The Problem With Disproofs Of Design
When I was attending geology field camp, a favorite pastime was hunting for arrowheads. There was no doubt about their authenticity. They were exquisitely chipped on both sides (in contrast to the clumsy modern ones sold in tourist traps) and made of obsidian, a rock not found in our field area. Most of my classmates did well to find one or two. I found dozens. In fact it got downright obscene. I found arrowheads in camp along trails that people had walked every day for weeks. The most surreal case was finding an arrowhead in my shoe one morning. I presume it was the gift of a pack rat because I guarantee none of my classmates would have given up a nice arrowhead for a practical joke!
I also found quite a few chips of red and yellow chert. They occurred in batches, and this rock, too, was foreign to the area, but I never found a full-fledged artifact of these materials. All things considered, I think it's safe to assume they were left by Indians.
At the opposite extreme of probability, the late anthropologist Louis Leakey spent a number of years excavating a site in the Calico Hills, California, convinced that he had discovered artifacts that pushed the arrival of humans in the Americas back to 100,000 years or more. The purported artifacts included flakes and crudely chipped pebbles. The problem is that the claimed artifacts come from an alluvial fan, not the gentlest depositional environment. With fist-sized pebbles being carried by flash floods, it would be surprising if there weren't a few that got chipped en route in a manner reminiscent of an artifact. Most geologists and anthropologists are convinced that's exactly what happened. (You'd never know this to look at most of the Web sites on the subject, which start at taking the artifacts at face value and drift off to the fringe from there. Very few pictures of the claimed artifacts are on line, something that hardly speaks well for their status as revolutionary discoveries or the confidence of their backers.)
So here we have chips, flakes, and chipped rocks. Are they artifacts of intelligent origin? In one case circumstantial evidence suggests they are, in the other case, not. But they're ambiguous. Maybe some single band of early humans got to Calico through some improbable series of adventures, lived for a while, then died out. We can never rule out the hypothesis short of a time machine.
Moral: If something looks complex enough to be of intelligent design, one possible interpretation is always that it is of intelligent design. It may not be, but in the absence of disconfirming evidence, intelligent design is always a viable hypothesis. We can say that it's not the only possible explanation, maybe even that it's not the most likely explanation, but it's extremely hard to dismiss the idea entirely. Intelligent design is always a possible interpretation of any sufficiently complex object.
[VII] Why Try to Disprove Design?
In his Enquiry, Hume accurately described the Argument From Design as "useless" because in and of itself it can never "establish any new principles of conduct and behavior." The Argument From Design only shows at best that there is intelligent design in the universe; it tells us nothing about whether the entity cares about human beings, communicates with them, or has moral scruples. Of itself, intelligent design does not validate any theology beyond deism.
On the other hand, intelligent design does not violate any known facts or logical principles. So why does it meet with such fierce opposition? True, many people leap immediately from the notion of intelligent design to the theology of their particular sect, but the proper response by anyone who claims intellectual rigor is to show the hidden assumptions in that leap of reasoning.
Still, it's legitimate to raise the possibility that order in the universe arises solely from the properties of the universe itself. Or is it? We know that some cases of complex order are the result of intelligent design. We do not know that any other origin for complex order is possible. What basis do we have even for postulating such a possibility? The bottom line is that none of the criticisms of the Argument From Design are compelled by any empirical or logical evidence; they are inspired solely by the desire to discredit the Argument From Design for the sake of discrediting it.
[VIII] The Red Herring
Parts X and XI are given over to a debate about suffering and its implications for a benevolent intelligence. Although any discussion about the nature of God has to confront this issue, it is completely premature in a debate about the existence of God. Most of Hume's readers, of course, would have thought in terms of either the God they pictured in their own theology, or no God at all (other conceptions of God being merely spurious fantasies). They would have considered Cleanthes' arguments for a benevolent intelligence inseparable from the issue of design in general. But that's no excuse for a modern reader to conflate the two issues.
[IX] Where Should We Look For Design?
It's worth looking at a list of what was not known in Hume's day:
Maxwell's Equations and the nature of electromagnetism
The Periodic Table
The structure of the atom
The nature of chemical reactions
Quantum Mechanics
Relativity
Genetics
The DNA code
Evolution by natural selection
The laws of thermodynamics
Spectroscopy
The nature of galaxies
So, although science was making thrilling progress in understanding the workings of the world, the "laws of nature" in Hume's day were mostly restricted to empirical descriptions of phenomena, and therefore the argument for and against design was waged mostly in the realm of complex natural phenomena. For every case Cleanthes can cite of two natural phenomena meshing smoothly together, Philo can cite a counter-example where the feedback fails. A century later Darwin's theory of evolution by natural selection would pretty much demolish this line of reasoning.
However, a modern day Cleanthes (as opposed to his semi-literate wannabes) wouldn't point to the way a hummingbird's bill is precisely shaped to fit a certain flower (or vice versa). He would point instead to the symmetries found in physics and the way a relatively small set of fundamental laws give rise to such a vast range of complex phenomena (the Cleanthes wannabes are mostly too illiterate even to have any idea of physics). He would also point to the fact that a very slight change in some fundamental constants would either have prevented complex atoms from forming at all, or would have allowed the stars to exhaust their nuclear fuel before life could evolve.
By way of analogy, consider a chess board well into the game. Is this a product of intelligent design? The pieces might very well look randomly arrayed, although a skilled player could easily spot that some arrangements cannot be achieved in normal play. For example, one side cannot lack a king, or have a pawn in its own back row. There is a checkmate position involving a king and two knights against a lone king, but it cannot be achieved in normal play (the lone king can always evade checkmate). But there would be many positions that are ambiguous. For every masterful position Cleanthes cites as clear evidence of intelligence, Philo cites one with two passed pawns. Cleanthes suggests that some positions are artificially created as problems; Philo accuses him of creating ad hoc excuses to avoid acknowledging failures of the design hypothesis. Cleanthes argues the pieces are clearly of intelligent manufacture; Philo notes that seashells are even more intricate and are wholly natural. Cleanthes points to the geometric regularity of the board; Philo cites crystals and honeycombs as equally regular but natural structures.
The reason chess has been played as long and seriously as it has is not because people like the pieces and the board (a nice chess board and set has esthetic appeal because of our reverence for the game), but because a very sparse set of rules leads to a fantastic variety of possible outcomes. And it's in the rules, not in the pieces, the board, or any particular arrangement on the board, that we must look for intelligence. (Chess isn't a perfect analogy. There are ad hoc rules like capturing en passant. The Japanese game Go might be a better analogy for pure intelligent design, but chess is more familiar.)
Philo, of course, has not been asleep at the wheel. He would point out that the beauty of chess is rooted in the underlying laws of logic and mathematics in the universe. He would also point to hypotheses that perhaps there are many universes, and we merely occupy one where the laws of physics allow matter to evolve into complex forms.
Cleanthes would wonder, in turn, why it's valid to criticize theological concepts as ad hoc, while it's simultaneously permissible to postulate the existence of universes whose existence is entirely unproven and which may be forever untestable. He'd also wonder why the order in the universe is such a pressing scientific problem as to justify postulating a vast number of alternate universes but not to justify postulating an intelligent designer.
The Case Against the Argument From Design
We cannot validly reason from earthly parallels to the Universe as a whole.
Since the creation of the universe was a unique event, we cannot say anything about it.
The order in nature could equally well result from the intrinsic properties of matter itself.
The existence of pain and suffering cast serious doubt on the existence of a benevolent Intelligence.
[I] Critique
The nature of science has changed dramatically since Hume's day, and the changes illustrate some holes in Philo's reasoning that probably would not have been apparent to Hume or anyone else at the time.
In Hume's day, the only rigorously known scientific laws were gravitation and Newton's laws of motion. The fact that these had successfully explained the motions of the planets had profoundly impressed all of society. Also, Newton had successfully explained why Kepler's empirical laws of planetary motion worked, and even made a correction to them. Still, nobody in Hume's day suspected the extent to which it would be possible to explain laws of nature in terms of still higher laws. Hume's trio was restricted to finding order in nature solely in the complex phenomena of the natural world, something that might not be the case today.
In Hume's day the stars were considered so inconceivably remote that it seemed impossible ever to have any real knowledge of them. Double stars, where one star orbits another, would be the first direct demonstration that gravitation applied among the stars. Spectroscopy, with its incredible power to analyze the physics and chemistry of the stars, was a century in the future. Quantum mechanics, which successfully explains what spectroscopy observes, was three quarters of a century beyond that. So we can forgive Hume for not envisioning how deeply we would be able to test the hypothesis that the laws of nature are the same everywhere. Nevertheless, Philo's argument that we cannot reason from earthly examples to the universe as a whole is flatly, definitively, wrong.
Mid-18th century Edinburgh was home to one of those brilliant collections of minds that appear from time to time, called the Scottish Enlightenment. Hume probably knew James Watt. A few years before the Dialogue was first published, Watt realized that existing steam engines were inefficient because they alternately heated and cooled the same vessel. He envisioned a completely new design in which spent steam was exhausted to a separate vessel to be condensed. His invention would launch the Industrial Revolution. So what? You envision a new way of doing things and build it. This is how technology works, right? Not in Hume's day. Hume could have Philo argue (Part VIII) "In all instances we have ever seen, ideas are copied from real objects...You reverse this order and give thought the precedence." The idea of conceiving something totally new and making it happen, the essence of modern technology, is completely opposite to the mental processes of Hume's time. We can forgive Hume for not foreseeing the extent to which abstract thought could precede the creation of objects, but again Philo's argument is flatly, definitively, wrong.
[II] A Sample With N = 1
"When two species of objects have always been observed to be conjoined together, I can infer, by custom, the existence of one wherever I see the existence of the other. And this I call an argument from experience. But how this argument can have place, where the objects ... are single, individual, without parallel, or specific resemblance, may be difficult to explain..... To ascertain this reasoning, it were requisite that we had experience of the origin of worlds..."
Here's another case where Hume utterly (and nobody can blame him) failed to foresee the growth of science. He would doubtless be astonished at how much we can infer about the origin of the universe.
But let's look at the validity of the argument even in Hume's day. The French mathematician Laplace would publish the first speculation on the origin of the solar system shortly after Hume's death. It simply is not true that we cannot reason about a unique event.
[III] Hume's Central Circularity
The issue to be decided is whether the order in nature is the result of intelligent design. If it is, then the properties of matter (the color, luster and density of gold, for example) are also the result of intelligent design. Postulating a dichotomy between intelligent design and the properties of matter therefore amounts to postulating a priori that there is no design in nature. Hume (and all who follow him) essentially follow a grand circularity:
Matter and the laws of nature are defined a priori to be separate from any intelligent design.
Order in nature is shown to be the result of the laws of nature and the properties of matter
Therefore order in nature is not the result of intelligent design
Nowhere is the circularity more blatant than Jacques Monod's Chance and Necessity. Monod starts by asking what criteria one would use for deciding something was intelligently designed and defines two criteria: repetition and geometric regularity. But, he hastens to add, these criteria apply only at the microscopic level. The distinction is entirely ad hoc because, if we applied it at the microscopic level, the Argument from Design would follow automatically. In any case, the distinction is nonsense, since macroscopic non-biological structures like crystals, cloud patterns and orbital resonances in the Solar System display repetition and geometric regularity, and microscopic structures like computer chips are of clearly intelligent origin (the bug in the first Pentium chip notwithstanding).
[IV] Lacuna Matata (Don't Sweat the Holes)
There's probably no greater lacuna in Hume's reasoning than in Part IX. Demea asks why there should be something rather than nothing, and why the universe we know instead of something else. By definition there can be no external cause, hence the only explanation is a logically necessary Being who "carries the Reason of his existence in himself, and who cannot be supposed not to exist without an express contradiction." (I run into people who quite literally cannot conceive of their religious beliefs being wrong, for whom the very concept of the Koran being wrong is a logical contradiction.)
Hume puts the reply in the mouth of Cleanthes, who says it only to forestall Philo. Hume presumably assigns this role to Cleanthes to spare Philo the burden of attacking every religious doctrine and thereby alienating readers, but it's quite definite here that Cleanthes is voicing Hume's own convictions. He says:
Nothing is demonstrable, unless the contrary implies a contradiction. Nothing, that is distinctly conceivable, implies a contradiction. Whatever we conceive as existent, we can also conceive as non-existent. There is no Being, therefore, whose non-existence implies a contradiction. Consequently there is no Being, whose existence is demonstrable.
This is essentially disproof by outright denial. We can conceive of God as non-existent, hence God cannot be logically necessary. The only thing missing is any proof that the conception of God as non-existent is valid even in principle. Cleanthes shortly cites the idea that 2 + 2 = 5 as an example of a logical contradiction. By the logic above, if I say I can conceive of 2 + 2 = 5 not being a contradiction, that makes it non-contradictory, since I can conceive of the contradiction being non-existent.
Cleanthes (Hume) goes on to say that the universe might well contain hidden attributes that would make its non-existence seem as contradictory as the non-existence of God. Considering how hard Hume hammers elsewhere at the unproven nature of religious conjectures and their ad hoc nature, postulating wholly unknown properties for the universe is a nice case of the pot calling the kettle black.
But there's more. Cleanthes (Hume) says the only argument that persuades him the universe (rather than God) is not the necessarily existent entity is the fact that we can validly conceive of it being different. "But it seems a great partiality not to perceive, that the same argument extends equally to the Deity." Let this soak in. The entire thrust of Hume's arguments up till now, mostly as voiced by Philo, have been that we cannot reason from our knowledge of design on earth to design in the universe. Now Hume uses Cleanthes to assert that because we can conceive of matter being different than it is, we are justified in conceiving of God being different than he is. If there is something about God that makes him logically necessary and immutable, it must be attributes we do not know, and we have no way of knowing whether the same qualities might not reside in nature. We're back to proof by postulating unknown hypothetical properties of the universe.
Hume essentially gets away with using mutually contradictory arguments by putting them in the mouths of two different characters, but nothing could be clearer than that Cleanthes, in this section, is relating Hume's ideas exactly.
[V] A Truly Weird Argument
In Part VII, Philo describes that in Indian mythology, the universe was spun by a great spider, and goes on to say:
And were there a planet wholly inhabited by spiders (which is very possible) this inference would there appear as natural and irrefragible as that which in our planet ascribes the origin of all things to design and intelligence, as explained by Cleanthes.
This argument is so wonderfully naive and blatantly anthropomorphic one hardly knows where to begin. A good starting point is to say duh..., any primitive intelligent species is likely to picture God as a larger version of itself. Spiders on this planet don't, as far as we know, have any conception of God so we don't need to worry about what they think, if indeed they have any more cognition than a personal computer.
So Philo's hypothetical spider planet would have to be inhabited by intelligent spiders. Just as human thinkers in Hume's day had long since concluded that it was mere imagination to picture God in human form, by the time Philo's spiders reached a similar level of development, the more intelligent ones should have gotten over their primitive arachnomorphism and reached the same conclusion. No doubt their artists would still picture God as a spider, but they would realize that was an image, not necessarily reality. (The only people on our planet who really seem to believe God is an old man with a long white beard are cartoonists and atheists.)
Spider webs, of course, are a matter of biology rather than conscious effort, but a race of spiders that remained at that level would be unlikely to have enough consciousness to speculate about God. Who knows what sorts of webs intelligent spiders might spin? (Just imagine the webs a spider mathematician might weave!) And even if we postulate a race of spiders that did nothing but spin webs and engage in philosophy while waiting for hapless flies, this argument still embodies the fundamental circularity of assuming that complexity in nature (spinnerets and spider webs in this case) are not the result of design, then using their "naturalness" to "prove" that the complexity is not the result of design.
[VI] The Problem With Disproofs Of Design
When I was attending geology field camp, a favorite pastime was hunting for arrowheads. There was no doubt about their authenticity. They were exquisitely chipped on both sides (in contrast to the clumsy modern ones sold in tourist traps) and made of obsidian, a rock not found in our field area. Most of my classmates did well to find one or two. I found dozens. In fact it got downright obscene. I found arrowheads in camp along trails that people had walked every day for weeks. The most surreal case was finding an arrowhead in my shoe one morning. I presume it was the gift of a pack rat because I guarantee none of my classmates would have given up a nice arrowhead for a practical joke!
I also found quite a few chips of red and yellow chert. They occurred in batches, and this rock, too, was foreign to the area, but I never found a full-fledged artifact of these materials. All things considered, I think it's safe to assume they were left by Indians.
At the opposite extreme of probability, the late anthropologist Louis Leakey spent a number of years excavating a site in the Calico Hills, California, convinced that he had discovered artifacts that pushed the arrival of humans in the Americas back to 100,000 years or more. The purported artifacts included flakes and crudely chipped pebbles. The problem is that the claimed artifacts come from an alluvial fan, not the gentlest depositional environment. With fist-sized pebbles being carried by flash floods, it would be surprising if there weren't a few that got chipped en route in a manner reminiscent of an artifact. Most geologists and anthropologists are convinced that's exactly what happened. (You'd never know this to look at most of the Web sites on the subject, which start at taking the artifacts at face value and drift off to the fringe from there. Very few pictures of the claimed artifacts are on line, something that hardly speaks well for their status as revolutionary discoveries or the confidence of their backers.)
So here we have chips, flakes, and chipped rocks. Are they artifacts of intelligent origin? In one case circumstantial evidence suggests they are, in the other case, not. But they're ambiguous. Maybe some single band of early humans got to Calico through some improbable series of adventures, lived for a while, then died out. We can never rule out the hypothesis short of a time machine.
Moral: If something looks complex enough to be of intelligent design, one possible interpretation is always that it is of intelligent design. It may not be, but in the absence of disconfirming evidence, intelligent design is always a viable hypothesis. We can say that it's not the only possible explanation, maybe even that it's not the most likely explanation, but it's extremely hard to dismiss the idea entirely. Intelligent design is always a possible interpretation of any sufficiently complex object.
[VII] Why Try to Disprove Design?
In his Enquiry, Hume accurately described the Argument From Design as "useless" because in and of itself it can never "establish any new principles of conduct and behavior." The Argument From Design only shows at best that there is intelligent design in the universe; it tells us nothing about whether the entity cares about human beings, communicates with them, or has moral scruples. Of itself, intelligent design does not validate any theology beyond deism.
On the other hand, intelligent design does not violate any known facts or logical principles. So why does it meet with such fierce opposition? True, many people leap immediately from the notion of intelligent design to the theology of their particular sect, but the proper response by anyone who claims intellectual rigor is to show the hidden assumptions in that leap of reasoning.
Still, it's legitimate to raise the possibility that order in the universe arises solely from the properties of the universe itself. Or is it? We know that some cases of complex order are the result of intelligent design. We do not know that any other origin for complex order is possible. What basis do we have even for postulating such a possibility? The bottom line is that none of the criticisms of the Argument From Design are compelled by any empirical or logical evidence; they are inspired solely by the desire to discredit the Argument From Design for the sake of discrediting it.
[VIII] The Red Herring
Parts X and XI are given over to a debate about suffering and its implications for a benevolent intelligence. Although any discussion about the nature of God has to confront this issue, it is completely premature in a debate about the existence of God. Most of Hume's readers, of course, would have thought in terms of either the God they pictured in their own theology, or no God at all (other conceptions of God being merely spurious fantasies). They would have considered Cleanthes' arguments for a benevolent intelligence inseparable from the issue of design in general. But that's no excuse for a modern reader to conflate the two issues.
[IX] Where Should We Look For Design?
It's worth looking at a list of what was not known in Hume's day:
Maxwell's Equations and the nature of electromagnetism
The Periodic Table
The structure of the atom
The nature of chemical reactions
Quantum Mechanics
Relativity
Genetics
The DNA code
Evolution by natural selection
The laws of thermodynamics
Spectroscopy
The nature of galaxies
So, although science was making thrilling progress in understanding the workings of the world, the "laws of nature" in Hume's day were mostly restricted to empirical descriptions of phenomena, and therefore the argument for and against design was waged mostly in the realm of complex natural phenomena. For every case Cleanthes can cite of two natural phenomena meshing smoothly together, Philo can cite a counter-example where the feedback fails. A century later Darwin's theory of evolution by natural selection would pretty much demolish this line of reasoning.
However, a modern day Cleanthes (as opposed to his semi-literate wannabes) wouldn't point to the way a hummingbird's bill is precisely shaped to fit a certain flower (or vice versa). He would point instead to the symmetries found in physics and the way a relatively small set of fundamental laws give rise to such a vast range of complex phenomena (the Cleanthes wannabes are mostly too illiterate even to have any idea of physics). He would also point to the fact that a very slight change in some fundamental constants would either have prevented complex atoms from forming at all, or would have allowed the stars to exhaust their nuclear fuel before life could evolve.
By way of analogy, consider a chess board well into the game. Is this a product of intelligent design? The pieces might very well look randomly arrayed, although a skilled player could easily spot that some arrangements cannot be achieved in normal play. For example, one side cannot lack a king, or have a pawn in its own back row. There is a checkmate position involving a king and two knights against a lone king, but it cannot be achieved in normal play (the lone king can always evade checkmate). But there would be many positions that are ambiguous. For every masterful position Cleanthes cites as clear evidence of intelligence, Philo cites one with two passed pawns. Cleanthes suggests that some positions are artificially created as problems; Philo accuses him of creating ad hoc excuses to avoid acknowledging failures of the design hypothesis. Cleanthes argues the pieces are clearly of intelligent manufacture; Philo notes that seashells are even more intricate and are wholly natural. Cleanthes points to the geometric regularity of the board; Philo cites crystals and honeycombs as equally regular but natural structures.
The reason chess has been played as long and seriously as it has is not because people like the pieces and the board (a nice chess board and set has esthetic appeal because of our reverence for the game), but because a very sparse set of rules leads to a fantastic variety of possible outcomes. And it's in the rules, not in the pieces, the board, or any particular arrangement on the board, that we must look for intelligence. (Chess isn't a perfect analogy. There are ad hoc rules like capturing en passant. The Japanese game Go might be a better analogy for pure intelligent design, but chess is more familiar.)
Philo, of course, has not been asleep at the wheel. He would point out that the beauty of chess is rooted in the underlying laws of logic and mathematics in the universe. He would also point to hypotheses that perhaps there are many universes, and we merely occupy one where the laws of physics allow matter to evolve into complex forms.
Cleanthes would wonder, in turn, why it's valid to criticize theological concepts as ad hoc, while it's simultaneously permissible to postulate the existence of universes whose existence is entirely unproven and which may be forever untestable. He'd also wonder why the order in the universe is such a pressing scientific problem as to justify postulating a vast number of alternate universes but not to justify postulating an intelligent designer.
