The Plantinga Obtusion: A Response to Alvin Plantinga's Response to The God Delusion

 Richard Dawkins' book "The God Delusion" is something of a staple text amongst many atheist circles. Not surprisingly, it is held in much lower-regard amongst many Christians, including Christian Philosopher Alvin Plantinga who - in 2007 - wrote a 13-page response to the book entitled "The

Dawkins Confusion".

For most of this post, I will be focusing on responding to the paper itself. Having said that, I know from experience that a good many atheists hear a term like "Christian Philosopher" and are wont to hold their heads in their hands and say something to the general effect of "Oh what pitiful stuff". So I would like to begin by establishing Dr. Plantinga's credentials, and thus why I would bother addressing his paper in the first place, before moving on to the paper itself.

Per his Wikipedia page, Plantinga is an American philosopher who works primarily in the fields of philosophy of religion, epistemology, and logic. He earned his Ph.D. in Philosophy from Yale University in 1958, and has taught at several universities since then. In 2014, Plantinga was the 30th most-cited contemporary author in the Stanford Encyclopedia of Philosophy. Plantinga also served as president of the American Philosophical Association, Western Division, from 1981 to 1982. and as President of the Society of Christian Philosophers from 1983 to 1986.

Dr. Alvin Plantinga

In addition to his Ph.D. he has honorary degrees from Glasgow University, Calvin University, North Park College, the Free University of Amsterdam, Brigham Young University, and Valparaiso University.
In 2006, the University of Notre Dame's Center for Philosophy of Religion renamed its Distinguished Scholar Fellowship as the Alvin Plantinga Fellowship.
In 2012, the University of Pittsburgh's Philosophy Department, History and Philosophy of Science Department, and the Center for the History and Philosophy of Science co-awarded Plantinga the Nicholas Rescher Prize for Systematic Philosophy.
In 2017, Baylor University's Center for Christian Philosophy inaugurated the Alvin Plantinga Award for Excellence in Christian Philosophy. Awardees deliver a lecture at Baylor University and their name is put on a plaque with Plantinga's image in the Institute for Studies in Religion.

In summary, we're not dealing with some two-penny slouch leaving tired and long-disproven memes on a facebook page. Dr. Plantinga is highly educated, matriculated from a prestigious university, and has received numerous awards and honors for his work as a philosopher and a theologian. I think it not at all unfair to say that he is widely recognized as a subject-matter expert in his fields (one hardly becomes the 30th-most-cited person in the Stanford Encyclopedia of Philosophy without having put in some effort and having gained some recognition for the quality of that effort). So, if Dr. Plantinga believes Dawkins' arguments in "The God Delusion" to be flawed, I think it is at least worth the time to read and assess what he has to say.

Plantinga's Case

Plantinga primarily focuses on Chapter 3 of Dawkins' book, which is entitled "Why There Almost Certainly is No God," having read it, I think it's fair to say that that chapter is basically the core of the book, so I think it's definitely fair to focus on it. Regarding this chapter, Plantinga writes:

Well, why does Dawkins think there almost certainly isn't any such person as God? It's because, he says, the existence of God is monumentally improbable. How improbable? The astronomer Fred Hoyle famously claimed that the probability of life arising on earth (by purely natural means, without special divine aid) is less than the probability that a flight-worthy Boeing 747 should be assembled by a hurricane roaring through a junkyard. Dawkins appears to think the probability of the existence of God is in that same neighborhood—so small as to be negligible for all practical (and most impractical) purposes. Why does he think so?

To make a couple of quick points right off the bat:

1. Dr. Hoyle's statement regarding the Boeing 747 was first made circa 1983. We have another 38 years of scientific advancements since he first made that statement. It's further worth noting that Dr. Hoyle is an astronomer, not a biologist. When making this statement, it is worth remembering that he is speaking FAR outside of his area of expertise.
2. Dr. Hoyle's specific claim is that the likelihood of "higher life forms" (such as fully-formed cells) arising by chance is about 1 in 1*10^40,000. The main problem with this statement is twofold:
1. Virtually no biologist believes that the first lifeform was a fully-formed cell. It's generally well-established at this point that cellular life is the result of evolution that took place long after the first life.
2. Life gets much simpler than a single-celled organism. For instance there is a "self-replicating" peptide that is a mere 32 amino acid molecules long. The odds of such a peptide arising by chance is actually only about 1 in 4.29*10^40. While that is certainly still astonishingly improbable, one should also remember that this isn't a case of nature only making one "attempt" at a time. A single kilogram of the amino acid arginine has 2.85 x 10^24 molecules in it, meaning that billions upon billions of random combinations of amino acids could occur simultaneously each week.

Unfortunately, even this simple opening from Dr. Plantinga is an example of Jonathan Swift's famous line "Falsehood flies, and the Truth comes limping after it". Dr. Hoyle's famous flowery metaphor about the Boeing 747 is a staple of Christian culture, while the sheer magnitude of the inaccuracy of the claim is all but unknown in the culture at large.

So now that our ideas of the improbability of the life arising by chance have been tempered by introducing facts to the flowery metaphors, let's continue.

The answer: if there were such a person as God, he would have to be enormously complex, and the more complex something is, the less probable it is: "However statistically improbable the entity you seek to explain by invoking a designer, the designer himself has got to be at least as improbable. God is the Ultimate Boeing 747." The basic idea is that anything that knows and can do what God knows and can do would have to be incredibly complex. In particular, anything that can create or design something must be at least as complex as the thing it can design or create... Therefore, he thinks, God would have to be monumentally complex, hence astronomically improbable; thus it is almost certain that God does not exist.

This seems to be a reasonable synopsis of Dawkins' position.

A Detour To The Blind Watchmaker

Prior to actually stating his issue with Dawkins' position as outlined above, Plantinga takes a slight detour to address an issue he has with Dawkins' previous work "The Blind Watchmaker", in which Dawkins argues that Evolution demonstrates that the world was not designed, stating:

Suppose the evidence of evolution suggests that all living creatures have evolved from some elementary form of life: how does that show that the universe is without design? ... [H]is claim is that the evidence of evolution reveals that evolution is unplanned, unguided, unorchestrated by any intelligent being.

But how could the evidence of evolution reveal a thing like that? After all, couldn't it be that God has directed and overseen the process of evolution? What makes Dawkins think evolution is unguided? 

I must say that, I am deeply disappointed to see a renowned philosopher resort to such shoddy argumentation. What Plantinga essentially is - perhaps unwittingly - doing here is creating a deity who is indistinguishable from random chance.

A cursory overview of Evolution indicates that mutations come from a variety of sources, such as solar radiation, errors that occur when DNA strands replicate, exposure to certain viruses, etc. Sometimes these mutations are harmful, sometimes they're helpful, sometimes they're neutral, and sometimes a single mutation can cause a "mixed bag" of multiple changes. There is nothing about this process that indicates that it's any sort of "steady march of progress", or that species tend to develop mutations that would benefit them (despite eating bamboo, Pandas still have not developed opposable thumbs that might better allow them to hold the bamboo more easily). Instead, what we see is a great variety of mutations, and whichever mutations allow for individuals to survive and reproduce more successfully get passed down to their offspring and eventually become more prevalent.

Nothing about this process requires oversight or direction, and nothing about the process even lends itself to the idea that it is guided. Sure, one could speculate that a deity is the one causing the mutations to occur, but again, not all of these mutations are useful. Mutations are as likely to be devastating as beneficial. To explain these mutations by saying that there is a deity overseeing them, we need to also posit either that the deity simply doesn't know how biology works or what mutations would be useful; or that the deity doesn't care if a great many of these creatures lead lives that are nasty, painful, and short; or we must fall back on the notion that the deity works in "mysterious ways" that are outwardly indistinguishable from random chance. None of these options answer any questions about evolution or add anything to our knowledge-base, or create any new testable hypotheses. We are simply introducing a premise that serves no function, while introducing new problems.

In short, evolution has no requirement of a deity to oversee it, introducing a deity as the overseer increases the complexity of the theory, while adding nothing to our understanding of evolution. Worse, adding a deity actually introduces a plethora of other questions (e.g. why so many mutations are useless or even harmful if this is a guided process) that quickly resolve themselves if we simply reject the premise that a deity is in any way involved.

Regrettably, Dr. Plantinga is not yet concluded with this line of inquiry, writing: 

What [Dawkins] does in The Blind Watchmaker, fundamentally, is three things. First, he recounts in vivid and arresting detail some of the fascinating anatomical details of certain living creatures and their incredibly complex and ingenious ways of making a living... Second, he tries to refute arguments for the conclusion that blind, unguided evolution could not have produced certain of these wonders of the living world—the mammalian eye, for example, or the wing. Third, he makes suggestions as to how these and other organic systems could have developed by unguided evolution.

Suppose he's successful with these three things: how would that show that the universe is without design? ... His detailed arguments are all for the conclusion that it is biologically possible that these various organs and systems should have come to be by unguided Darwinian mechanisms (and some of what he says here is of considerable interest). What is truly remarkable, however, is the form of what seems to be the main argument. The premise he argues for is something like this:

1. We know of no irrefutable objections to its being biologically possible that all of life has come to be by way of unguided Darwinian processes;

and Dawkins supports that premise by trying to refute objections to its being biologically possible that life has come to be that way. His conclusion, however, is

2. All of life has come to be by way of unguided Darwinian processes.

It's worth meditating, if only for a moment, on the striking distance, here, between premise and conclusion. The premise tells us, substantially, that there are no irrefutable objections to its being possible that unguided evolution has produced all of the wonders of the living world; the conclusion is that it is true that unguided evolution has indeed produced all of those wonders. The argument form seems to be something like

We know of no irrefutable objections to its being possible that p;
Therefore
p is true.

Philosophers sometimes propound invalid arguments (I've propounded a few myself); few of those arguments display the truly colossal distance between premise and conclusion sported by this one. I come into the departmental office and announce to the chairman that the dean has just authorized a $50,000 raise for me; naturally he wants to know why I think so. I tell him that we know of no irrefutable objections to its being possible that the dean has done that. My guess is he'd gently suggest that it is high time for me to retire.

What strikes me most about this passage is the gross misrepresentation of Dawkins' argument. Dr. Plantinga starts off well enough, noting that Dawkins provides examples of how various organs and biological traits could arise from natural methods, and that he also refutes arguments that these traits could not have arisen without divine guidance. However, by the very next paragraph, Plantinga appears to have forgotten about Dawkins' examples of how structures could arise without divine intervention and now believes that Dawkins' entire argument is essentially "There's no proof that it didn't happen this way, ergo it happened this way."

Perhaps, if one were to give Dawkins a particularly uncharitable reading, one could interpret Dawkins to be saying "There's no proof that it didn't happen this way, ergo it happened this way." After all, surely he did not go into great detail about every mechanism of evolutionary theory. The problem there is that evolution is the most-studied scientific discipline in history. More research has been done, more evidence gathered, more hypotheses tested and re-tested in the field of evolution, than in any other field. To do justice to the sheer amount of data collected on evolution would the work of a volume 10 times the length of "The Blind Watchmaker". Nevertheless, he did - by Dr. Plantinga's own admission - provide examples of the ways in which even highly complex structures could arise by random mutation and natural selection. As such, Plantinga should have characterized Dawkins' argument as:

1. All available evidence supports the idea that all of life has come to be by way of unguided Darwinian processes.

2. We know of no irrefutable objections to its being biologically possible that all of life has come to be by way of unguided Darwinian processes.

3. If all available evidence supports the idea that life has come to be by way of unguided Darwinian processes, and all known objections can be refuted, then the idea that all life has come to be by way of unguided Darwinian processes should be accepted as true.

From there, the conclusion "All of life has come to be by way of unguided Darwinian processes." (or, at the very least, that we should accept it as true until there is some compelling evidence to the contrary) is easily reached.

Returning to Topic: Is God Complex?

Having ended the detour, Dr. Plantinga is finally ready to tell us his objection to Dawkins' claim that God must be more complex (and thus more improbable) than the world that he is alleged to explain.

First, is God complex? According to much classical theology (Thomas Aquinas, for example) God is simple, and simple in a very strong sense, so that in him there is no distinction of thing and property, actuality and potentiality, essence and existence, and the like... (It isn't only Catholic theology that declares God simple; according to the Belgic Confession... God is "a single and simple spiritual being.")... More remarkable, perhaps, is that according to Dawkins' own definition of complexity, God is not complex. According to his definition (set out in The Blind Watchmaker), something is complex if it has parts that are "arranged in a way that is unlikely to have arisen by chance alone." But of course God is a spirit, not a material object at all, and hence has no parts. A fortiori (as philosophers like to say) God doesn't have parts arranged in ways unlikely to have arisen by chance. Therefore, given the definition of complexity Dawkins himself proposes, God is not complex.

Now, I will admit, the first time that I read this, my immediate gut reaction was something like "Who CARES if classical theology says that God is simple? Theologists are basically just making this all up as they go, there's no evidence to support any of their claims!"

That said, to be fair to Christians, let me actually address this as a serious point: First of all, to say that God is "simple" is to say that god has no parts and cannot be meaningfully divided in any physical or metaphysical way. I would liken this a bit to a ball of clay, any one "part" of the ball is completely identical to every other part, and so the attempt to divide it is entirely arbitrary and not particularly meaningful. (Of course, the doctrine of the Trinity rips some pretty nasty holes in the notion of God's simplicity, but Christianity has never been able to form a coherent understanding of the Trinity, so I will do them the favor of side-stepping the issue of the Trinity altogether.)

Now, Plantinga takes the matter a step further by not merely stating that God has no metaphysical or spiritual "parts", but that - in The Blind Watchmaker - Dawkins describes complexity purely in terms of physical parts, and ergo that is the definition we must use in reading The God Delusion.

There is a general principle in Philosophy that one ought to give an author a "charitable reading", to assume that they are a generally intelligent person, and to attempt to read their work in the spirit intended, rather than necessarily nitpick at word choice or seek to deliberately misconstrue. Plantinga's decision to pick out a definition that Dawkins used in a separate work and apply it to the current conversation with no concern for whether it would be sensible to do so, strikes me as a conscious decision to deny Dawkins the courtesy of a charitable reading of his work.

A more charitable reading might note that complexity can be spoken of in many ways aside from the material. We could speak of the complexity of the human mind in terms of neurons, but we could also speak of it in terms of the breadth and depth of thought that humans are capable of. That we can learn farming, and architecture, and engineering, and that we can develop complex systems of writing, and that some people can speak a half-dozen languages or more. While computers can certainly outperform us in math, the impact of having one letter wrong in a line of code, versus having one letter wrong in an instruction manual, demonstrates that humanity's ability to adapt and to process "corrupted data" is astonishing.

If the human mind is complex, how much more complex must a mind be that is alleged to know how to bring matter into existence from nothing, to form planets and stars, to organize DNA, and to cause Electrons to have a negative charge. To characterize such a mind a "simple" merely because it doesn't have physical parts, is to fail to engage the discussion in good faith.

Similarly, it is not merely physical properties, but psychological attributes that can influence both complexity and probability.

To draw a more "concrete" example before moving on to a more abstract one, consider: Let us say that you and I are in a vast room. Inside of this room is everything that could ever hypothetically exist. Boxes, Books, Cars, Unicorns, UFOs... all of it. You name it, there's one in this room.

I pick out an item at random and I ask you, "what is more likely, that this item weighs at least one pound, or that it weighs at least ten pounds"?

Despite the fact that you don't know anything about the item that I've picked out, the safe bet is to say "it weighs at least one pound", because any object that weighs at least ten pounds, by definition must also weigh at least 1 pound. The Venn Diagram for "things that weigh at least 1 pound" and "things that weigh at least 10 pounds" is a pair of circles in which the latter is entirely encompassed by the former, since anything that weighs 10 pounds or more must - by definition - also weigh 1 pound or more.

To this concept to psychological traits, allow me to ask: For any being that has a mind, what is more likely: that this being is at least intelligent enough to feed itself, or that this being is at least intelligent enough to build an automobile?

If we think about all the different types of creatures out there, plenty of them are intelligent enough to feed themselves: Cows, horses, birds, humans, koalas (although koalas just barely make the cut), etc. On the other hand comparatively few (basically only humans) are intelligent enough to build automobiles. As in the case of the weight of an object, there are simply more creatures that know how to feed themselves than who know how (or are capable of learning how) to build cars, so for any given creature, it's more probable that they're intelligent enough to feed themselves than that they're intelligent enough to build a car.

In short, the lower you set the bar, the easier it is to leap over it. If you set the bar so low that basically everyone can get over it, it's a simple matter of showing that that there exists an entity that can clear that bar. Meanwhile, the higher you set the bar, the less likely it is that there exists a being who can clear it.

Bearing that in mind, what is most likely:

That there is a being who knows some things, there is a being who knows most things, or that there is a being who knows ALL things?

That there is a being who has some power or agency in the world, that there is a being who has a lot of power or agency in the world, or that there is a being who is ALL-powerful?

That there is a being who is fair some of the time, or a being who is ALL-just?

That there is a being who shows mercy from time to time, or a being who is ALL-merciful?

So many traits are ascribed to Yahweh, omniscience, omnipotence, omnibenevolence, omnipresent... he is said to be All-just, All-loving, All-merciful, All-graceful, All-glorious... I think we have the picture. For each trait assigned to Yahweh, that's another bar, raised to the highest height, and each bar makes it that much less likely likely that there exists a being who can clear all of them.

To Recap: Yahweh psychological attributes suffice to show that he would be an incredibly complex (and thus supremely improbable) being, regardless of theology's insistence that he has no "parts".

From Bad Arguments to Bad Metaphysics

Unfortunately, Dr. Plantinga is not yet done with us, indeed we are only about half way through his paper at this point. Moving forward, Plantinga chooses, for the sake of argument, to simply grant that God is complex and hopes to argue that complexity would not necessarily mean improbability, writing:

So why think God must be improbable? According to classical theism, God is a necessary being;... he exists in all possible worlds. But if God is a necessary being, if he exists in all possible worlds, then the probability that he exists, of course, is 1, and the probability that he does not exist is 0.... So if Dawkins proposes that God's existence is improbable, he owes us an argument for the conclusion that there is no necessary being with the attributes of God —an argument that doesn't just start from the premise that materialism is true. Neither he nor anyone else has provided even a decent argument along these lines; Dawkins doesn't even seem to be aware that he needs an argument of that sort.

Contrary to Plantinga's final assertion, I see no reason why Dawkins needs an argument of the sort that Plantinga describes. It is true that classical theism has held that God is a necessary being. That is essentially the goal of every ontological argument for the existence of God. The problem with such ontological arguments is that no one has ever produced one that was compelling to anyone who did not already have a vested interest in believing it. For instance, consider the "original" ontological argument put forth by Anselm, Archbishop of Canterbury in 1077 CE:

1. God is defined as the greatest possible being that can be imagined.
2. God exists as an idea in the mind.
3. A being that exists as an idea in the mind and in reality is, other things being equal, greater than a being that exists only as an idea in the mind.
4. Thus, if God exists only as an idea in the mind, then we can imagine something that is greater than God (that is, a greatest possible being that does exist).
5. But we cannot imagine something that is greater than God (for it is a contradiction to suppose that we can imagine a being greater than the greatest possible being that can be imagined.)
6. Therefore, God exists.

What this essentially says is "because we can imagine that God exists, then God exists." It is functionally a desperate hope that we can conjure God into existence by the power of wishful thinking.

If there are any readers here who think that there might be something to Anselm's argument, allow me to pose the following exercise.

1. Imagine the greatest island that you can imagine.
2. Clearly this island exists in your mind since you're imagining it right now.
3. But surely that island would be greater if existed both in your mind AND in reality, than if it exists only as an idea in the mind.
4. Thus, if this island exists only as an idea in your mind, then you can imagine an island that is greater (that is, a greatest possible island that does exist).
5. But - by definition - you cannot imagine an island greater than the greatest imaginable island!
6. Therefore, the island you're imagining actually exists in reality.

It should be obvious to everyone that our reasoning has gone wrong somewhere because otherwise we've just proven that an island that you just imagined must actually exist, which is ludicrous even at first blush.

From Bad Metaphysics to Bad Physics

Plantinga's next attempt is to make use of the "argument from design" or "fine-tuning argument", but not quite in the way one might expect. He begins with a handful of typical fine tuning arguments:

For example, if the force of gravity were even slightly stronger, all stars would be blue giants; if even slightly weaker, all would be red dwarfs; in neither case could life have developed. The same goes for the weak and strong nuclear forces; if either had been even slightly different, life, at any rate life of the sort we have, could probably not have developed.

Of course each of these falls prey to a sort of "Survivorship bias". Every time we hear someone say "when I was young we didn't have seat belts and we were fine!" and utterly ignores all of the people who died (and still die) each year from not using seat belts, that is survivorship bias. When Christians argue that the Earth is perfectly suited to support life (and ignore the 99% of all species that have gone extinct over the eons) that is survivorship bias. When Plantinga himself says "at any rate life of the sort we have, could probably not have developed" he acknowledges the possibility that life still could have developed if any of these allegedly finely-tuned forces were different, just that it would not have been the life that actually developed. He ignores all of the other types of life that may have hypothetically developed, to focus on the kind that actually did, and then claims that the world is fine-tuned to us, rather than us being adapted to the world.

Despite the fact that he - in noting the possibility of other sorts of life arising if the universe were different than it actually is - has already given the lie to the various fine-tuning arguments, he apparently still thinks that Dawkins and others need a good rebuttal to them.

Dawkins, along with others, proposes that possibly there are very many (perhaps even infinitely many) universes, with very many different distributions of values over the physical constants. Given that there are so many, it is likely that some of them would display values that are life-friendly. So if there are an enormous number of universes displaying different sets of values of the fundamental constants, it's not at all improbable that some of them should be "fine-tuned." We might wonder how likely it is that there are all these other universes, and whether there is any real reason (apart from wanting to blunt the fine-tuning arguments) for supposing there are any such things.

Now, it is true that some physicists subscribe to notions of multiple universes for reasons related to quantum mechanics. It is far beyond my expertise to say if such ideas are actually sensible or not. I am not a quantum physicist and I'm not going to sit here and pretend to be. What I will say is that there is no reason to posit possible universes in order to explain the origin of life. It is estimated that there are something in the neighborhood of 1*10^24 stars in the universe, and it is estimated that there are - on average - roughly as many planets as stars. That's roughly 1,000,000,000,000,000,000,000,000 planets where life could hypothetically have developed. We only know that life developed on 1 of those locations. Hardly what one would expect of a deity that intentionally fine-tuned the universe to support life. However, given so many planets, the odds that at least one of them might happen to have conditions that allow for life appear much less far-fetched.

However, Plantinga has anticipated an objection of this sort, and is ready with is reply.

But concede for the moment that indeed there are many universes and that it is likely that some are fine-tuned and life-friendly. That still leaves Dawkins with the following problem: even if it's likely that some universes should be fine-tuned, it is still improbable that this universe should be fine-tuned. …the odds that [our universe] should be fine-tuned are exceedingly, astronomically low, even if it's likely that some universe or other is fine-tuned.

What is Dawkins' reply? He appeals to "the anthropic principle," the thought that the only sort of universe in which we could be discussing this question is one which is fine-tuned for life...

But how does that so much as begin to explain why it is that [our universe] is fine-tuned? ... It still seems striking that these constants should have just the values they do have; it is still monumentally improbable, given chance, that they should have just those values; and it is still much less improbable that they should have those values, if there is a God who wanted a life-friendly universe.

Since I have not granted the existence (or necessity) of multiple universes, let us substitute "planet" for "universe" in the above quote, as I believe that does not change the substance of the argument. In both cases the heart of the issue is "Why is the place in which we actually exist well-suited to life, rather than some other place? That seems highly unlikely that it should be this place that is the good one."

It is worth noting that the final statement, that it is "less improbable" that the world should be well suited to life if there is a God who wanted a life-friendly world, is only true if it were actually true that God is not supremely improbable. If he is not "the ultimate Boeing 747". As Dr. Plantinga has yet to convincingly demonstrate this, the conclusion is questionable at best.

That said, his question of "how does that explain why our universe is fine-tuned?" I think has some merit at least insofar as it is a common question in Christian circles. However, I think the question rests on an implied premise that is desperately in want of justification: That there is something profoundly special and important about the fact that we reside on this planet (or in this particular universe) rather than some other.

If one does not view the fact that humans came to exist on Earth as profoundly and deeply meaningful, the explanation offered by the Anthropic Principle falls neatly into place: of the roughly 1,000,000,000,000,000,000,000,000 planets in the universe, all surrounding stars of various types, and orbiting them at various distance, and having upon them various elements in various proportions, it seems fairly likely that one of them should happen by random chance to be able to support life. By definition, life (and - by extension - humanity) could only hypothetically come to exist on such a planet. So, far from the planet being suited to us, we are the result of billions of years of life constantly either adapting itself to the planet, or perishing, the result thus being a race of creatures who now marvel at how well the home and the inhabitants are suited for one another.

So "why is it this planet that's capable of sustaining life?" Random chance. If you throw enough planets at the wall, some of them will stick. Were it not this planet then - statistically speaking - it would be some other planet, and the inhabitants of that planet would be asking the exact same question. Sure, it's not a grandiose explanation like "The Earth is well-suited for human life because it is the centerpiece of an almighty God's creation, which God created expressly to house His children, whom He crafted in His own image". Saying "it's this planet because - statistically speaking - it had to be one of them" doesn't necessarily fill one with the same sense of glorious purpose. But it is a much simpler answer, doesn't require a deity to make it work, and doesn't require us to come up with an answer as to why a deity whose intent was to "fine-tuned" the universe so that it could support life, ended up with a universe in which the vast majority of planets appear to be utterly incapable of supporting life.

Circling Back to the Question of Complexity

Here Dr. Plantinga circles back around to his original point: his disagreement with the notion of God's complexity. Here he quotes The God Delusion directly, writing:

Organized complexity is the thing that we are having difficulty in explaining. Once we are allowed simply to postulate organized complexity, if only the organized complexity of the DNA/protein replicating machine, it is relatively easy to invoke it as a generator of yet more organized complexity… . But of course any God capable of intelligently designing something as complex as the DNA/protein machine must have been at least as complex and organized as that machine itself… . 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.

Plantinga argues against Dawkins here, writing:

...suppose we land on an alien planet orbiting a distant star and discover machine-like objects that look and work just like tractors; our leader says "there must be intelligent beings on this planet who built those tractors." A first-year philosophy student on our expedition objects: "Hey, hold on a minute! You have explained nothing at all! Any intelligent life that designed those tractors would have to be at least as complex as they are." No doubt we'd... advise him to take the next rocket ship home and enroll in another philosophy course or two. For of course it is perfectly sensible, in that context, to explain the existence of those tractors in terms of intelligent life, even though (as we can concede for the moment) that intelligent life would have to be at least as complex as the tractors. The point is we aren't trying to give an ultimate explanation of organized complexity... we are only trying to explain one particular manifestation of it (those tractors). And (unless you are trying to give an ultimate explanation of organized complexity) it is perfectly proper to explain one manifestation of organized complexity in terms of another. Similarly, in invoking God as the original creator of life, we aren't trying to explain organized complexity in general, but only a particular kind of it, i.e., terrestrial life. So even if (contrary to fact, as I see it) God himself displays organized complexity, we would be perfectly sensible in explaining the existence of terrestrial life in terms of divine activity.

I fully grant that it is perfectly acceptable to explain one specific instance of organized complexity with another. We explain the computers, tractors, homes, books, etc, by pointing to the humans who created or assembled them. Given the complexity of our bodies, the number of cells and organs working together to allow us to be alive, etc. I fully grant that humans are also examples of organized complexity, and yet it is not inappropriate to explain these other examples of organized complexity by pointing to humans as the creators. That said, it seems profoundly disingenuous to claim that - by invoking God - Christians are only attempting to explain one particular instance of organized complexity (i.e. terrestrial life) rather than providing an ultimate explanation of organized complexity. Christianity almost universally holds that Yahweh is the unmoving mover, the uncreated creator, the author of all that is, was, and ever will be. The story of Genesis 1 is not merely a story of the creation of humans, but of the universe itself. The fact of the matter is, that Christianity almost universally holds that Yahweh is the ultimate explanation of organized complexity, and so Dawkins' objection that Christianity attempts to explain organized complexity by reference to a still-more-complex being, stands firm against this objection.

One Last Attempt For a "Gotcha" Moment

To conclude his paper, Dr. Plantinga takes aim at Dawkins' beliefs about perception writing:

...Dawkins endorses a certain limited skepticism. Since we have been cobbled together by (unguided) evolution, it is unlikely, he thinks, that our view of the world is overall accurate; natural selection is interested in adaptive behavior, not in true belief... Like most naturalists, Dawkins is a materialist about human beings: human persons are material objects; they are not immaterial selves or souls or substances joined to a body, and they don't contain any immaterial substance as a part. From this point of view, our beliefs would be dependent on neurophysiology, and (no doubt) a belief would just be a neurological structure of some complex kind. Now the neurophysiology on which our beliefs depend will doubtless be adaptive; but why think for a moment that the beliefs dependent on or caused by that neurophysiology will be mostly true? Why think our cognitive faculties are reliable?

This is a good question. "Are our cognitive faculties are reliable?" is a major question in philosophy of perception. Every time that someone poses the question "what if, when I look at a red thing, and you look at a red thing, we see two totally different colors?" That is essentially a way of asking "Do our minds perceive the world as it actually is, or do they each perceive the world differently?" Plantinga expounds on this question further, writing:

From a theistic point of view, we'd expect that our cognitive faculties would be (for the most part, and given certain qualifications and caveats) reliable. God has created us in his image, and an important part of our image bearing is our resembling him in being able to form true beliefs and achieve knowledge. But from a naturalist point of view the thought that our cognitive faculties are reliable (produce a preponderance of true beliefs) would be at best a naïve hope. The naturalist can be reasonably sure that the neurophysiology underlying belief formation is adaptive, but nothing follows about the truth of the beliefs depending on that neurophysiology. In fact he'd have to hold that it is unlikely, given unguided evolution, that our cognitive faculties are reliable. It's as likely, given unguided evolution, that we live in a sort of dream world as that we actually know something about ourselves and our world.

Plantinga thus concludes that - because Dawkins must believe his own cognitive faculties to be unreliable - he should not believe his reasons for disbelieving in God to be reliable.

Now, the first flaw in this reasoning is the conflation of the words "true" and "reliable". Plantinga clearly believes that only "true" perceptions are "reliable" and vice versa. However, that position is not necessarily justified. As an (admittedly hyperbolic) example, let's suppose that "in reality" black widow spiders look like the most adorable teacup pigs you've ever seen in your life. Suppose that our brains falsely portray them as "creepy crawlies" because they are highly venomous and portraying them as being distasteful drives us away and keeps us alive. In such a case, our cognitive faculties would not be giving us "true" information. Our perceptions of black widow spiders would be clearly untrue, but that does not make them unreliable. We can still trust our perceptions to give us actionable information (e.g. that that is a black widow and we should stay away on pain of death).

Now, while that example is likely an exaggeration of what our brains actually do, there is some evidence to suggest that our brains have evolved to favor usefulness over "Capital T" Truth. In the article Natural Selection and Veridical Perceptions published in the Journal of Theoretical Biology, the authors provide some evidence that - in cases where the most "useful" or "actionable" information is not "Capital T" True information - evolution would favor presenting information in the way that is most usable, rather than the way that is most true. The authors liken this to the a computer monitor. You may have an internet shortcut in the top left of your desktop, but that doesn't mean that the internet lives in the top left of your desktop. Your desktop shortcut is a way of portraying the inner workings of the computers code, but it does not show you "True" inner workings of the code ("the 1s and 0s" so to speak).

Despite the display on your monitor it not actually being "true", creating that representation of the computer's coding and presenting the information as a shortcut on a desktop, is the way that is most useful to the typical computer user. (Dr. Donald Hoffman writes about this at length in The Interface Theory of Perception.) That the monitor is not showing the "True" inner workings of the computers code changes nothing about the fact that you can double-click the internet shortcut and have the internet come up. The information presented on the monitor is useful, and reliably so, despite not being "True" in a robust sense of the word.

In short, Dr. Plantinga is half-correct about how our cognitive faculties would work from a "naturalist perspective" while it is likely that our perceptions are not all true, it is quite likely that our perceptions reliably show us the world in the way that allows us to make the most use of the information provided. So while, again, our perceptions may not always be "Capital T" True, it would hardly be fair to consider them "unreliable". 

Having said that, I think that Plantinga's attempt at showing why Yahweh is necessary for knowledge introduces more problems than it answers. After all, if "an important part of our image bearing is our resembling [Yahweh] in being able to form true beliefs and achieve knowledge", then Plantinga owes us an explanation of why our cognitive faculties would only be reliable "for the most part, and given certain qualifications and caveats". One would think that a perfect God who desires for us resemble him in our ability to form true beliefs would not subject that resemblance to terms and conditions. And yet the wide variety of illusions, sleights of hands, fallacies, heuristics and the like that our minds are liable to fall victim to, show that our cognitive faculties are indeed only "mostly reliable" at best.

So, far from demonstrating that we cannot trust our senses if there is no God, Plantinga has only shown that sometimes our perceptions are not "True" because our ability to make use of the information is better served by it being presented in a way that is less "True" but more accessible, while simultaneously presenting a problem for himself as he now has to explain why God would desire for us to have "Capital T" True perceptions, while leaving our minds vulnerable to a wide variety of cognitive pitfalls.

In Closing

It seems that, for all of his accomplishments as a philosopher, when it comes to defending Christianity, Dr. Plantinga puts his philosophical training in the closet and generally trots out the same poor arguments that we might expect of any common evangelist. None hold up to scrutiny, and the evidence available continues to show us that - when it comes to understanding the world that we live in - Yahweh remains an unnecessary hypothesis.