Where the Conflict Really Lies: Science, Religion, and Naturalism (36 page)

All we’re ordinarily told is that this necessity is weaker than logical necessity (the laws of nature are not logically necessary), but still stronger than mere universal truth (not all true universal generalizations are necessary in this sense). But what
is
this necessity? What is its nature? This is the real rub. It seems impossible to say what it is. The philosopher David Armstrong at one time spoke of laws as involving a necessitating relationship among universals: a law is just the expression of a certain necessary relationship between universals.
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But, as David Lewis pointed out, naming this relation “necessity” doesn’t tell us much. It also doesn’t mean that it really
is
necessity—anymore, said Lewis, than being named “Armstrong” confers mighty biceps.
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Armstrong added that the class of propositions necessary in this sense is larger than the class of logically necessary propositions, but smaller than that of true propositions. But this too is no real help: any class of true propositions that includes all the logically necessary propositions, but doesn’t include all true propositions, meets this
condition. (For example, the class of true propositions minus the proposition
China is a large country
meets this condition: but obviously this tells us nothing about the intended sense of “necessary.”) Armstrong later decided that the laws of nature are logically necessary after all, prompted no doubt by the difficulty of saying what this other brand of necessity might be. It is also this difficulty, one suspects, that prompts others who hold that the laws of nature, despite appearances to the contrary, are logically necessary.

Theism offers important resources here: we can think of the necessity of natural law both as a consequence and also as a sort of measure of divine power. Natural laws, obviously enough, impose limits on our technology. We can do many wonderful things: for example, we can fly from Paris to New York in less than four hours. No doubt our abilities along these lines will continue to expand; perhaps one day we will be able to travel from Paris to New York in under four minutes. Even so, we will never be able to travel to the nearest star, Proxima Centauri, in less than four years. That is because Proxima Centauri is about 4.3 light years from us, and
c
, the velocity of light, is an upper limit on the relative velocity of one body with respect to another.
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That it
is
such an upper limit, we think, is a natural law. But the distance to
Proxima Centauri
is such that if I were to travel there (in a spaceship, say) in less than four years, my velocity with respect to the earth would have to exceed that limit. And if, indeed, this restriction on the relative velocities of moving objects
is
a law of nature, we won’t be able to manage that feat, no matter how hard we try, and no matter how good our technology.

From a theistic perspective, the reason is that God has established and upholds this law for our cosmos, and no creature (actual or
possible) has the power to act contrary to what God establishes and upholds. God is omnipotent; there are no non-logical limits on his power; we might say that his power is infinite. The sense in which the laws of nature are necessary, therefore, is that they are propositions God has established or decreed, and no creature—no finite power, we might say—has the power to act against these propositions, that is, to bring it about that they are false. It is as if God says: “Let
c
, the speed of light, be such that no material object accelerates from a velocity less than
c
to a velocity greater than
c
”; no creaturely power is then able to cause a material object to accelerate from a velocity less than
c
to one greater than
c
. The laws of nature, therefore, resemble necessary truths in that there is nothing we or other creatures can do to render them false. We could say that they are
finitely inviolable
.

Though these laws are finitely inviolable, they are nevertheless contingent, in that it is not necessary, not part of the divine nature, to institute or promulgate just
these
laws. God could have created our world in such a way that the speed of light should have been something quite different from
c
; he could have created things in such a way that Newton’s laws don’t hold for middle-sized objects. As we saw in
chapter 7
on fine-tuning, there are many physical constants that are finitely inviolable (
we
can’t change them) but could have been different and are therefore contingent. The natural laws are finitely inviolably, but not necessarily true.

Still further, these laws are not like the laws of the Medes and Persians (see
chapter 3
); it is not true that once God has established or instituted them, they limit or constrain his power to act. As we saw in
chapter 3
, this is a bit tricky. Say that God acts specially in the world when he acts in a way that goes beyond creation and conservation. We can then think of the natural laws as of the following form:

When God is not acting specially, p.

For example,

When God is not acting specially, no material object accelerates from a speed less than
c
to a speed greater than
c
.

But of course that doesn’t mean that
God
cannot bring it about that some material object accelerate from a speed less than
c
to one greater than
c
. Neither we nor any other creature can do this; it doesn’t follow that God cannot. If the laws take the above form they are really conditionals: the antecedent of a law specifies that God is not acting specially, and the consequent is a proposition describing how things ordinarily work, how they work when God is not acting specially. For example, when God isn’t acting specially, no material object accelerates through the speed of light, any two objects attract each other with a force directly proportional to the product of their masses and inversely proportional to the square of the distance between them, and so on. The thing to see is that while no creatures, no finite beings, can bring about a state of affairs incompatible with the consequent of a law, God has the power to do so.

With respect to the laws of nature, therefore, there are at least three ways in which theism is hospitable to science and its success, three ways in which there is deep concord between theistic religion and science. First, science requires regularity, predictability, and constancy; it requires that our world conform to laws of nature. In the west (which includes the United States, Canada, Europe, and, for these purposes, Australia and New Zealand) the main rival to theism is naturalism, the thought that there is no such person as God or anything like God. Naturalism is trumpeted by, for example, three of the four horsemen of atheism: Richard Dawkins, Daniel Dennett,
and Christopher Hitchens.
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(The fourth horseman, Sam Harris, is an atheist, all right, but doesn’t seem to rise to the lofty heights—or descend to the murky depths—of naturalism: he displays a decided list towards Buddhism.
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) From the point of view of naturalism, the fact that our world displays the sort of regularity and lawlike behavior necessary for science is a piece of enormous cosmic luck, a not-to-be-expected bit of serendipity. But regularity and lawlikeness obviously fit well with the thought that God is a rational person who has created our world, and instituted the laws of nature.

Second, not only must our world in fact manifest regularity and law-like behavior: for science to flourish, scientists and others must
believe
that it does. As Whitehead put it (earlier in this chapter): “There can be no living science unless there is a widespread instinctive conviction in the existence of an
Order of Things
;” such a conviction fits well with the theistic doctrine of the image of God.

Third, theism enables us to understand the necessity or inevitableness or inviolability of natural law: this necessity is to be explained and understood in terms of the difference between divine power and the power of finite creatures. Again, from the point of view of naturalism, the character of these laws is something of an enigma. What is this alleged necessity they display, weaker than logical necessity, but necessity nonetheless? What if anything explains the fact that these laws govern what happens? What reason if any is there for expecting them to continue to govern these phenomena? Theism provides a natural answer to these questions; naturalism stands mute before them.

The distinguished scientist Eugene Wigner spoke of the “unreasonable efficacy of mathematics in the natural sciences.”
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What might he have meant? Mathematics and natural science in the West have developed hand in hand, from the Leibniz/Newton discovery of the differential calculus in the seventeenth century to the non-Abelian gauge theory of contemporary quantum chromodynamics. Much of this mathematics is abstruse, going immensely beyond the elementary arithmetic we learn in grade school. Why should the world be significantly describable by
these
mathematical structures? Why should these complex and deep structures be applicable in interesting and useful ways?

Perhaps you will claim that no matter how the world had been, it would have been describable by mathematics of some kind or other. Perhaps so; but what is unreasonable, in Wigner’s terms, is that the sort of mathematics effective in science is extremely challenging mathematics, though still such that we human beings can grasp and use it (if only after considerable effort). No matter how things had been, perhaps there would have been mathematical formulas describing the world’s behavior. For example, here is one way things could have been: nothing but atomless gunk with nothing happening. I guess there could be mathematical descriptions of such a reality, but they would be supremely uninteresting. Here is another way things could have been: lots of events happening in kaleidoscopic variety and succession, but with no rhyme or reason, no patterns, or at any rate no patterns discernible to creatures
like us. Here too mathematical description might be possible: event A happened and lasted ten seconds; then event B happened and lasted twice as long as A; then C happened and had more components than A, and so on. But again, under that scenario the world would not be mathematically describable in ways of interest to creatures with our kinds of cognitive faculties. Still a third way things could have been: there could have been surface variety and chaos and unpredictability with deep regularity and law—so deep, in fact, as to be humanly inaccessible.

All of these are ways in which mathematical description would be possible; these ways would also be of no interest to us. What Wigner notes, on the other hand, is that our world is mathematically describable in terms of fascinating underlying mathematical structures of astounding complexity but also deep simplicity. To discover it has required strenuous and cooperative effort on the part of many scientists and mathematicians. That mathematics of this sort should be applicable to the world is indeed astounding. It is also properly thought of as unreasonable, in the sense that from a naturalistic perspective it would be wholly unreasonable to expect this sort of mathematics to be useful in describing our world. It makes eminently good sense from the perspective of theism, however. Science is a splendid achievement, and much of its splendor depends upon mathematics being applicable to the world in such a way that it is both accessible to us but also offers a challenge of a high order. According to theism, God creates human beings in his image, a crucial component of which is the ability to know worthwhile and important things about our world. Science with its mathematical emphasis is a prime example of this image in us: science requires our very best efforts—both as communities and individuals—and it delivers magnificent results. All of this seems wholly appropriate from a theistic point of view; as Paul Dirac, who came up with an influential formulation of quantum theory, put it, “God is a mathematician of a very high order and He
used advanced mathematics in constructing the universe.”
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So here we have another manifestation of deep concord between science and theistic religion: the way in which mathematics is applicable to the universe.

Just as it is unreasonable, from a naturalistic perspective, to expect mathematics of this sort to be efficacious, so it is unreasonable, from that perspective, to expect human beings to be able to grasp and practice the kind of mathematics employed in contemporary science. From that point of view, the best guess about our origins is that we human beings and our cognitive faculties have come to be by way of natural selection winnowing some form of genetic variation. The purpose of our cognitive faculties, from that perspective, is to contribute to our reproductive fitness, to contribute to survival and reproduction. Current physics with its ubiquitous partial differential equations (not to mention relativity theory with its tensors, quantum mechanics with its non-Abelian group theory, and current set theory with its daunting complexities) involves mathematics of great depth, requiring cognitive powers going enormously beyond what is required for survival and reproduction. Indeed, it is only the occasional assistant professor of mathematics or logic who needs to be able to prove Gödel’s first incompleteness theorem in order to survive and reproduce.

These abilities far surpass what is required for reproductive fitness now, and even further beyond what would have been required for reproductive fitness back there on the plains of Serengeti. That sort of ability and interest would have been of scant adaptive use in
the Pleistocene. As a matter of fact, it would have been a positive hindrance, due to the nerdiness factor. What prehistoric female would be interested in a male who wanted to think about whether a set could be equal in cardinality to its power set, instead of where to look for game?
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