A Living, Intelligent Universe

A fascinating article in the December 23, 2013 issue of The New Yorker discusses the latest research on the behavior of plants, and the disputes among scientists as to whether this indicates that plants have intelligence.  In brief, the article summarizes research indicating the following:  Plants can sense light, moisture, gravity, and pressure, and they use these inputs to determine an optimal growth path.  In addition, plants can sense a variety of chemicals and microbes in soil, as well as chemical signals from other plants.  One scientists estimates that an average plant has three thousands chemicals in its vocabulary.  When plants are attacked or injured, whether by insects, animals, or humans, they produce an anesthetic.  In fact, many of the chemicals we use today, from caffeine to aspirin and other drugs, were originally developed by plants as defense mechanisms against attack.  Plants under attack will also emit a chemical distress signal to other plants, which prompts the other plants to initiate their own defense mechanisms (for example, plants will produce toxins that make them less tasty or digestible to animals, or they will emit signals to predator insects who will attack the plant-eating insects).  Plants compete with other plants for resources, but they also cooperate with each other to an amazing degree, sharing resources with younger or weaker plants.  In fact, trees employ an underground fungi to exchange resources as well as information.  Scientists have jokingly referred to this exchange system as the “wood-wide web.”

Most of these observations regarding plant behavior are not disputed among scientists.  What is disputed is the issue of whether or not this behavior constitutes intelligence.  There is a consensus that plants do not have a central organ that performs the functions of a brain, and it is agreed that plants do not have the abstract reasoning skills that a human being would have.  However, a number of scientists argue that such a definition of intelligence is too restrictive.  They propose that plants do have intelligence, defined as “an intrinsic ability to process information from both abiotic and biotic stimuli that allows optimal decisions about future activities in a given environment.”  Or more simply, says one scientist, “Intelligence is the ability to solve problems.”  In fact, this same scientist is currently working with a computer scientist to design a plant-based computer, “modeled on the distributed computing performed by thousands of roots processing a vast number of environmental variables.”  Such an attempt would build upon previous efforts to construct computers based on the information processing capabilities of slime molds and DNA molecules.

What is fascinating about this new research is that it continues a trend in human knowledge in which our initial criteria for intelligent life has had to be gradually expanded to include more and more species formerly regarded as mindless.  This raises the issue: is there in fact a clear dividing line between mindless matter and intelligent life, or is there simply a continuum, with human beings having the most advanced intelligence, animal and plant life having a more primitive intelligence, and the fundamental components of matter (molecules, atoms, physical forces, etc.) having a very primitive form of embedded intelligence.  In this view, the components of matter do not have consciousness in the same way that humans or animals do, but they do “know” how to do certain things.  In the case of the components of matter, they may “know” only how to do one or two things, such as form combinations with other components of matter.  But even this primitive knowledge is a form of knowledge nonetheless.

Viewing intelligence as something inherent in all things is part of the theory of hylozoism, which posits that the entire universe is in some sense alive.  Hylozoism goes back to the ancient Greek philosophers and has been proposed at various times by different thinkers since then.  The Renaissance friar and scientist Giordano Bruno was a proponent of hylozoism, among other heresies, and was burnt at the stake by the Catholic Church.

Is viewing the universe as alive and intelligent outrageous?  Consider the definition of “intelligence” put forth by the scientists studying plant life: the ability to “process information” or “solve problems.”  This definition actually encompasses many or most of the functions of the physical laws of the universe, according to many physicists.  In their view, the universe can be conceptualized as an information-processing mechanism, a vast computer.  In fact, the 19th century English mathematician Charles Babbage, who built the first mechanical calculating device and is widely known as the “father of the computer,” believed that the universe could indeed be conceptualized as an immense computer, with the laws of the universe serving as the program.

This view of universal intelligence is not the same as the traditional view of an omniscient and omnipotent being standing above the universe and directing all of its affairs — which is why Giordano Bruno was burned at the stake.  But the view of a universe with an embedded intelligence existing in all things is an intriguing alternative to the view that sees a sharp distinction between intelligent beings — divine or human — and allegedly mindless matter.  Rather than viewing the universe as something mindless that is acted upon by an external intelligence, perhaps it is better to conceive of the universe as having an inherent intelligence that grows more complex over time.

Omnipotence and Human Freedom

Prayson Daniel writes about Christian author C. S. Lewis’s attempt to deal with the problem of evil here and here.  Lewis, who suffered tragic loss at an early age, became an atheist when young, but later converted to Christianity.  Lewis directly addressed the challenge of the atheists’ argument — why would an omnipotent and benevolent God allow evil to exist? — in his books The Problem of Pain and Mere Christianity.

Central to Lewis’s argument is the notion that the freedom to do good or evil is essential to being human.  If human beings were always compelled to do good, they would not be free, and thus would be unable to attain genuine happiness.

One way to illustrate the necessity of freedom is to imagine a world in which human beings were unable to commit evil — no violence, no stealing, no lying, no cheating, no betrayal.  At first, such a world might appear to be a paradise.  But the price would be this: essentially we would all be nothing but robots.  Without the ability to commit evil, doing good would have no meaning.  We would do good simply because we were programmed or compelled to do nothing but good.  There would be no choices because there would be no alternatives.  Love and altruism would have no meaning because it wouldn’t be freely chosen.

Let us imagine a slightly different world, a world in which freedom is allowed, but God always intervenes to reward the good and punish the guilty.  No good people ever suffer.  Earthquakes, fires, disease, and other natural disasters injure and kill only those who are guilty of evil.  Those who do good are rewarded with good health, riches, and happiness.  This world seems only slightly better than the world in which we are robots.  In this second world, we are mere zoo animals or pets.  We would be trained by our master to expect treats when we behave and punishment when we misbehave.  Again, doing good would have no meaning in this world — we would simply be advancing our self-interest, under constant, inescapable surveillance and threat of punishment.  In some ways, life in this world would be almost as regimented and monotonous as in the world in which we are compelled to do good.

For these reasons, I find the “free will” argument for the existence of evil largely persuasive when it comes to explaining the existence of evil committed by human beings.  I can even see God as having so much respect for our freedom that he would stand aside even in the face of an enormous crime such as genocide.

However, I think that the free will argument is less persuasive when it comes to accounting for evils committed against human beings by natural forces — earthquakes, fires, floods, disease, etc.  Natural forces don’t have free will in the same sense that human beings do, so why doesn’t God intervene when natural forces threaten life?  Granted, it would be asking too much to expect that natural disasters happen only to the guilty.  But the evils resulting from natural forces seem to be too frequent, too immense, and too random to be attributed to the necessity of freedom.  Why does freedom require the occasional suffering and death of even small children?  It’s hard to believe that small children have even had enough time to live in order to exercise their free will in a meaningful way.

Overall, the scale of divine indifference in cases of natural disaster is too great for me to think that it is part of a larger gift of free will.  For this reason, I am inclined to think that there are limits on God’s power to make a perfect world, even if the freedom accorded to human beings is indeed a gift of God.

Miracles

The Oxford English Dictionary defines a “miracle” as “a marvelous event occurring within human experience, which cannot have been brought about by any human power or by the operation of any natural agency, and must therefore be ascribed to the special intervention of the Deity or some supernatural being.”  (OED, 1989)  This meaning reflects how the word “miracle” has been commonly used in the English language for hundreds of years.

Since a miracle, by definition, involves a suspension of physical laws in nature by some supernatural entity, the question of whether miracles take place, or have ever taken place, is an important one.  Most adherents of religion — any religion — are inclined to believe in miracles; skeptics argue that there is no evidence to support the existence of miracles.

I believe skeptics are correct that the evidence for a supernatural agency occasionally suspending the normal processes and laws of nature is very weak or nonexistent.  Scientists have been studying nature for hundreds of years; when an observed event does not appear to follow physical laws, it usually turns out that the law is imperfectly understood and needs to be modified, or there is some other physical law that needs to be taken into account.  Scientists have not found evidence of a supernatural being behind observational anomalies.  This is not to say that everything in the universe is deterministic and can be reduced to physical laws.  Most scientists agree that there is room for indeterminacy in the universe, with elements of freedom and chance.  But this indeterminacy does not seem to correspond to what people have claimed as miracles.

However, I would like to make the case that the way we think about miracles is all wrong, that our current conception of what counts as a miracle is based on a mistaken prejudice in favor of events that we are unaccustomed to.

According to the Oxford English Dictionary, the word “miracle” is derived from the Latin word “miraculum,” which is an “object of wonder.” (OED 1989)  A Latin dictionary similarly defines “miraculum” as “a wonderful, strange, or marvelous thing, a wonder, marvel, miracle.” (Charlton T. Lewis, A Latin Dictionary, 1958)  There is nothing in the original Latin conception of miraculum that requires a belief in the suspension of physical laws.  Miraculum is simply about wonder.

Wonder as an activity is an intellectual exercise, but it is also an emotional disposition.  We wonder about the improbable nature of our existence, we wonder about the vastness of the universe, we wonder about the enormous complexity and diversity of life.  From wonder often comes other emotional dispositions: astonishment, puzzlement, joy, and gratitude.

The problem is that in our humdrum, everyday lives, it is easy to lose wonder.  We become accustomed to existence through repeated exposure to the same events happening over and over, and we no longer wonder.  The satirical newspaper The Onion expresses this disposition well: “Miracle Of Birth Occurs For 83 Billionth Time,” reads one headline.

Is it really the case, though, that a wondrous event ceases to be wondrous because it occurs frequently, regularly, and appears to be guided by causal laws?  The birth of a human being begins with blueprints provided by an egg cell and sperm cell; over the course of nine months, over 100,000,000,000,000,000,000,000,000 atoms of oxygen, carbon, hydrogen, nitrogen and other elements gradually come together in the right place at the right time to form the extremely intricate arrangement known as a human being.  If anything is a miraculum, or wonder, it is this event.  But because it happens so often, we stop noticing.  Stories about crying statues, or people seeing the heart of Jesus in a communion wafer, or the face of Jesus in a sock get our attention and are hailed as miracles because these alleged events are unusual.  But if you think about it, these so-called miracles are pretty insignificant in comparison to human birth.  And if crying statues were a frequent event, people would gradually become accustomed to it; after a while, they would stop caring, and start looking around for something new to wonder about it.

What a paradox.  We are surrounded by genuine miracles every day, but we don’t notice them.  So we grasp at the most trivial coincidences and hoaxes in order to restore our sense of wonder, when what we should be doing is not taking so many wonders for granted.

How Powerful is God?

In a previous post, we discussed the non-omnipotent God of process theology as a possible explanation for the twin facts that the universe appears to be fine-tuned for life and yet evolution is extremely slow and life precarious.  The problem with process theology, however, is that God appears to be extremely weak.  Is the concept of a non-omnipotent God worthwhile?

One response to this criticism is that portraying God as weak simply because the universe was not instantaneously and perfectly constructed for life is to misconstrue what the meaning of “weak” is.  The mere fact that the universe, consisting of a least 10,000,000,000,000,000,000,000 stars, was created out of nothingness and has lasted over 13 billion years does not seem to indicate weakness.

Another response would be that the very gradual incrementalism of evolution may be a necessary component of a fantastically complex system that cannot tolerate errors that would threaten to destroy the system.  That is, the various physical laws and numerical constants that underlie the order of the universe exist in such an intricate relationship that a violation of a law in one particular case or sudden change in one of the constants would cause the universe to self-destruct, in the same way that a computer program may crash if a single line of code is incorrect or is incompatible with the other lines of code.

In fact, a number of physicists have explicitly described the universe as a type of computer, in the sense that the order of the universe is based on the processing of information in the form of the physical laws and constants.  Of course, the chief difference between the universe and a computer is that we can live with a computer crashing occasionally — we cannot live with the universe crashing even once.  Thus the fact that the universe, while not immortal, never seems to crash, indicates that gradual evolution may be necessary.  Perhaps instability on the micro level of the universe (an asteroid occasionally crashing into a planet with life) is the price to be paid for stability on the macro level.

Alternatively, we can conceptualize the order behind the universe as a type of mind, “mind” being defined broadly as any system for processing information.  We can posit three types of mind in the historical development of the universe: cosmic mind (God), biological mind (human/animal mind), and electronic mind (computer).

Cosmic mind can be thought of as pure spirit, or pure information, if you will.  Cosmic mind can create matter and a stable foundation for the universe, but once matter is created, the influence of spirit on matter is relatively weak.  That is, there is a division between the world of spirit and the world of matter that is difficult to bridge.  Biological mind does not know everything cosmic mind does and it is limited in time and space, but biological mind can more efficiently act on matter, since it is part of the world of matter.  Electronic mind (computer) is a creation of biological mind but processes larger amounts of information more quickly, assisting biological mind in the manipulation of matter.

As a result, the evolution of the universe began very slowly, but has recently accelerated as a result of incremental improvements to mind.  According to Stephen Hawking,

The process of biological evolution was very slow at first. It took two and a half billion years, to evolve from the earliest cells to multi-cell animals, and another billion years to evolve through fish and reptiles, to mammals. But then evolution seemed to have speeded up. It only took about a hundred million years, to develop from the early mammals to us. . . . [W]ith the human race, evolution reached a critical stage, comparable in importance with the development of DNA. This was the development of language, and particularly written language. It meant that information can be passed on, from generation to generation, other than genetically, through DNA. . . .  [W]e are now entering a new phase, of what might be called, self designed evolution, in which we will be able to change and improve our DNA. . . . If this race manages to redesign itself, to reduce or eliminate the risk of self-destruction, it will probably spread out, and colonise other planets and stars.  (“Life in the Universe“)

According to physicist Freeman Dyson (Disturbing the Universe), even if interstellar spacecraft achieve only one percent of the speed of light, a speed within the possibility of present-day technology, the Milky Way galaxy could be colonized end-to-end in ten million years –  a very long time from an individual human’s perspective, but a remarkably short time in the history of evolution, considering it took 2.5 billion years simply to make the transition from single-celled life forms to multi-celled creatures.

So cosmic mind can be very powerful in the long run, but patience is required!

A Universe Half Full?

It has often been said that the difference between a pessimist and an optimist is that a pessimist sees a half-poured beverage as a glass half empty, whereas an optimist sees the glass as being half full.  I think the decision to adopt or reject atheism may originate from such a perspective — that is, atheists see the universe as half empty, whereas believers see the universe as half full.  We all go through life experiencing events both good and bad, moments of joy, beauty, and wonder, along with moments of despair, ugliness, and boredom.  When we experience the positive, we may be inclined to attribute purpose and benevolence to the universal order; when we experience the negative, we may be more apt to attribute disorder and meaninglessness to the universe.

So, is it all a matter of perspective?  If we are serious thinkers, we have to reject the conclusion that it is merely a matter of perspective.  Either there is a God or there isn’t.  If we are going to explain the universe, we have to explain everything, good and bad, and not neglect facts that don’t fit.

The case for atheism is fairly straightforward: the facts of science indicate a universe that is not very hospitable to either the emergence of life or the protection of life, which greatly undercuts the case for an intelligent designer.  Most planets have no life, except perhaps for the most primitive, insignificant forms of life.  Where life does exist, life is precarious and cruel; on a daily basis, life forms are attacked and destroyed by hostile physical forces and other life forms.  There is not the slightest historical and archeological evidence of a “golden age” or a “Garden of Eden” which once existed but was lost because of man’s sinfulness; life has always been precarious and cruel.  Even where life has developed, it has developed in a process of very gradual evolution, consisting of much randomness, over the course of billions of years.  And even despite progress after billions of years, life on earth has been subject to occasional mass extinction events, from an asteroid or comet striking the planet, to volcanic eruptions, to dramatic climate change.  Even if one granted that God created life very gradually, the notion that God would allow a dumb rock from space to wipe out the accomplishments of several billions of years of evolution seems inexplicable.

The case for belief in God rests on a contrary claim, namely that order in the universe is too complex and unusual to be explained merely by reference to purposeless physical laws and random events.  It may appear that physical laws operate without apparent purpose, such as when an asteroid causes mass extinction, and evolution certainly consists of many random events.  But there is too much order to subscribe to the view that the universe is nothing but blind laws and random events.  When one studies the development of the stars and planets and their predictable motions, the vast diversity and complexity of life on earth, and the amount of information contained in a single DNA molecule, randomness is not the first thing one thinks of.  Total randomness implies total disorder and a total lack of pattern, but the randomness we see in the universe takes place within a certain structure.  If you roll a die, there are six possible outcomes; if you flip a coin there are two possible outcomes.  Both actions are random, but a structure of order determines the range of possible outcomes.  Likewise, there is randomness and disorder in the universe, but there is a larger structure of order that provides general stability and restricts outcomes.  Mutations take place in life forms, but these mutations are limited and incremental, restricting the range of possible outcomes and allowing the development of new forms of life on top of old forms of life.

Physicists tend to agree that we appear to live in a universe “fine-tuned” for life, in the sense that many physical constants can only exist with certain values, or life would not be able to evolve.  According to Stephen Hawking, “The laws of science, as we know them at present, contain many fundamental numbers, like the size of the electric charge of the electron and the ratio of the masses of the proton and electron. . . . The remarkable fact is that the values of these numbers seem to have been very finely adjusted to make possible the development of life.”  Physicist Paul Davies writes:

 [L]ife as we know it depends very sensitively on the form of the laws of physics, and on some seemingly fortuitous accidents in the actual values that nature has chosen for various particle masses, force strengths, and so on. . . . [I]f we could play God, and select values for these quantities at whim by twiddling a set of knobs, we would find that almost all knob settings would render the universe uninhabitable.  In some cases it seems as if the different knobs have to be fine-tuned to enormous precision if the universe is to be such that life will flourish. (The Mind of God, pp. 199-200).

The counterargument to the “fine-tuned” argument is that there could exist many universes that self-destruct in a short period of time or don’t have life — we just happen to live in a fine-tuned universe because only a fine-tuned universe can allow the existence of life forms that think about how fine-tuned the universe is!  However, this argument rests on the hypothetical belief that many alternative universes have existed or do exist, and until there is evidence for other universes, it must remain highly speculative.

So how do we reconcile the two sets of facts presented by the atheists and the believers?  On the one hand, the universe appears to allow life to develop only extremely gradually under often hostile conditions, with many setbacks along the way.  On the other hand, the universe appears to be fine-tuned to support life, suggesting some sort of cosmic purpose or intelligence.

In my view, the only way to reconcile the two sets of facts is to conceive of God as being very powerful, but not omnipotent.  (See a previous posting on this subject.)  According to process theology, God’s power is not coercive but persuasive, and God acts over long periods of time to create.  Existing things are not subject to total central control, but God can influence outcomes.

An analogy could be made with the human mind and its control over the body.  It is easy to raise one’s right arm by using one’s thoughts, but to pitch a fastball, play a piano, or make a high-quality sculpture requires a level of coordination and skill that most of us do not have — as well as an extraordinary amount of training and practice.  In the course of life, we attempt many things, but are never successful at all we attempt; in fact, the ambitions in our minds usually outpace our physical abilities.  Some people do not even have the ability to raise their right arm.  The relation of a cosmic mind to the “body” of the universe may be similar in principle.

Some would object that the God of process theology is ridiculously weak.  A God that has only the slightest influence over matter and cannot even stop an asteroid from hitting a planet does not seem like a God worth worshiping or even respecting.  In fact, why do we even need the concept of a weak God — wouldn’t we be better off without it?  I will address this topic in a future posting.

God as Love

The Greek philosopher Empedocles wrote that the universe was characterized by conflict between two cosmic forces, Love and Strife.  In his view, the universe originally existed in a state of perfect love and unity, with no distinct elements or separate life forms.  However, the force of Strife emerged and began to destroy this unity; separate parts broke off from the whole, forming the elements of matter.  The attractive force of Love exerted its remaining influence by bringing the elements together in different combinations, creating animals and humans.  But these beings were mortal, as the force of Strife gradually pulled the elements apart again, leading to disintegration and death.

There are obviously fascinating parallels between Empedocles’ philosophy and Christianity in terms of the centrality of love, though in contrast to Christianity, Empedocles viewed cosmic history as cyclic.  But whether we accept Greek philosophy or Christianity, or both, is it helpful in understanding the order of the universe If we think of God as Love?

From a purely scientific standpoint, the notion that particles come together to form larger structures, including life forms, because of love sounds ridiculous.  Do hydrogen atoms really come together with oxygen atoms to form water because of love?  It makes no sense, many would argue, to anthropomorphize mindless matter and attribute human desire and emotion to particles.  However, I would argue that it makes sense to think of love as a broader phenomenon of attraction, with attraction between humans being a highly complex and sophisticated type of love, attraction between animals being a less complex type of love, and attraction between particles being a very primitive type of love, but love nevertheless.

Although it used to be thought that animals had no real emotions, we now know that animals do have emotions, that they are capable of love between their own kind and love of those from other species.  The question of whether insects have emotions is less settled, though some scientists who study the issue argue that at least some insects have primitive emotional responses originating in rudimentary brain structures.

It seems unlikely that there would be emotions in lower life forms, such as cells and bacteria.  However, even though we can’t know exactly how lower life forms “feel,” scientific studies have demonstrated forces of attraction and repulsion even in these lower life forms.  Paramecium will swim away from unfavorable environments (such as cold water), but remain in favorable environments (containing warm temperatures and/or the presence of food).  Egg cells in both humans and animals will exercise choice in determining which sperm cells with which to join, weeding out bad sperm cells from good.  In fact, the human body itself has been described as a cooperative “society of cells.”

Given that forces of attraction and repulsion exist in even the lowest life forms, is it really absurd to posit such forces as affecting even atomic and subatomic particles?  I believe that the general principle is the same, if love is defined simply as an attractive force that brings separate entities together to form a greater whole.  The only difference is that the principle is expressed in a very primitive form among lower forms of order and in a more sophisticated form among higher forms of order, such as animals and humans.

Physical Laws and the Mind of God

The American philosopher of science Charles Sanders Peirce once wrote that the physical laws of the universe were the expression of an evolving cosmic mind.  As he put it, physical laws were the outcome of a mind become habitual: “matter is effete mind, inveterate habits becoming physical laws.”  However, he notes that the cosmic mind is not merely habitual, but has a powerful element of indeterminacy and spontaneity, which is why the universe continues to evolve and to produce life.  The evolution of the universe, in Peirce’s view, is the gradual crystallization of mind.

There is much merit to Peirce’s idea — rather than seeing the physical laws of the universe as separate entities that pop out of nowhere and have no unifying foundation, Peirce’s concept expresses the underlying unity and order of the universe, which is still developing even as the human mind itself develops.

One criticism of conceptualizing the physical laws of the universe as being part of a cosmic mind is that physical laws by their nature have an unvarying determinism and regularity that contradicts the notion of a conscious being capable of thinking, planning, and exercising free will in order to shape events.  But the physical laws of the universe are really only part of the universal order.  On the large, astronomical scale certainly, there is determinism and regularity; but on the very small, subatomic scale, there is a high degree of indeterminism and unpredictability; and life forms have the freedom to partially evade or escape the bounds of physical determinism.  In this conception, determinism and regularity provide a foundation of order on which freedom and creativity can flourish.  One can analogize this conception with the human mind, in which many essential functions of the brain (control of breathing, heart rate, sensation) occur mostly or entirely without conscious planning or control in the lower part of the brain (the “brainstem”), while higher thought processes are conducted on top of this primitive foundational order.

Granted, there are limits to employing the metaphor of “mind” to the cosmic order, as there are with any metaphor.  But metaphors are often a necessary tool to describe things that simply can’t be communicated with literal precision.  Even the most rigorous and skeptical of scientists cannot do without metaphors.  The “physical laws” of the universe is itself a metaphor; the “Big Bang” is a metaphor; and the “selfish gene” is a metaphor.

Omnipotence of God

 Is [God] willing to prevent evil, but not able? then is he impotent. Is he able, but not willing? then is he malevolent. Is he both able and willing? whence then is evil?   —  David Hume

The passage  above from the Scottish philosopher David Hume succinctly summarizes the reasoning behind the decisions of many to adopt the position of atheism, whether they are aware of Hume or not.  In fact, the challenge posed by this short argument has rarely been answered to the complete satisfaction of many.  Theodicy is the term that has been used to denote philosophies that have attempted to reconcile God and the existence of evil.

In the Judeo-Christian tradition, God is conceived as having the attribute of omnipotence, which is usually defined as unlimited power, the ability to do whatever one wants.  However, this conception of God was not held by many ancient Greek and Roman philosophers, who saw God as being very powerful but not all-powerful.  The Roman physician and philosopher Galen argued that God was limited by necessity and matter — God could not do whatever he wanted, and this conception was different from the Jewish and Christian conception:

This is where our opinion, and that of Plato and all others among the Greeks who correctly deal with the rationality of Nature, differs from that of Moses.  For Moses, it is sufficient to say merely that God “willed” to order the universe in a certain way, and it was done.  For he [Moses] thinks that everything is possible for God, even if he wanted to make a horse or a bull out of ashes.  But we know that is not the case.  We say, on the contrary, that certain things are impossible by nature.  God does not even attempt those things, but from what is possible, he chooses the best to come about.  (On the Usefulness of the Parts of the Body, quoted in Dale B. Martin, Inventing Superstition )

In this view, the existence of evil does not pose a problem for the existence of God, because God is not all-powerful to begin with — God is simply very powerful.

In the contemporary, popular view, the conception of God as being less than all-powerful is regarded as blasphemous, ridiculous, or self-contradictory.  However, the notion of limitations on God’s power is found in a number of prominent Christian theologians, including Paul Tillich, Reinhold Niebuhr, Edgar S. Brightman, and Martin Luther King, Jr.  In fact, there is an entire school of thought known as “Process Theology,” that conceives of God as being limited in power and acting gradually on the world over time.  This alternative conception of God is not an entirely satisfactory answer to the problem of evil, but I would argue that it holds much fewer difficulties than the popular conception of a God who can do whatever He wants but chooses not to.  It is also superior to an atheism that sees the universe as being composed merely of a set of physical laws and random events with no underlying, unifying, intelligent order.