Van Huyssteen J.W. (editor) Encyclopedia of Science and Religion

Подождите немного. Документ загружается.

DIVINE ACTION

— 219—

history of divine action receives its definitive artic-

ulation in the text of Qurhan given by Allah to the

Prophet Mohammed. Each of these religions of the

book places stories of divine action at the center of

its understanding of God; God is known, in part,

as the One Who Acts in these ways, and diver-

gences in the stories told by these traditions con-

tribute crucially to differences in their conceptions

of the character and purposes of God. The canon-

ical narratives, therefore, do not remain simply a

record of past understandings of God’s activity;

rather they set the context within which communi-

ties of faith interpret their contemporary experi-

ence as part of an ongoing history of divine action

in the world.

Modern challenges

In addition to playing this central role in the theis-

tic traditions, the idea that God acts in the world

raises a host of difficult questions. The transition

from sacred stories to theological claims about di-

vine action involves subtle interpretive judgments.

The biblical texts, for example, do not speak with

a single voice, but rather depict God in strikingly

diverse ways; in order to construe them as con-

tributing to a relatively unified narrative of God’s

acts, decisions must be made about which ele-

ments are central and which are peripheral, and

these theological choices can generate a wide

range of different readings. Further, modern tech-

niques of critical scholarship have contributed

greatly to understanding the literary forms, func-

tions, and history of these texts. One effect of this

scholarship has been to show how complicated it

is to move from scriptural stories to conclusions

about historical events. A theologian who appeals

to biblical and liturgical talk about God’s mighty

acts in history must think through what this lan-

guage means once it is granted that the stories are

not straightforward reports of surprising things that

happened long ago. If, for example, one acknowl-

edges the legendary and symbolic character of sig-

nificant aspects of the exodus story, and if one

doubts that each of the miraculous divine inter-

ventions occurred just as it is related in the text,

then what should one say about what God did to

liberate the Hebrew people from slavery in Egypt?

This is a question that Langdon Gilkey (1919– )

pressed with great effectiveness against the biblical

theology movement, represented by theologians

like G. Ernest Wright (1909–1974) and Reginald H.

Fuller (1915– ), who insisted that God is known

through mighty acts in history but who were un-

willing to take at face value the biblical stories of

those acts.

The natural sciences raise additional powerful

questions for traditional claims about divine action.

In a prescientific view of the world, one com-

pelling way to make sense of events is to ascribe

them to the action of person-like but super-human

powers. With the rise of the sciences, these super-

natural agencies and teleological (i.e., purposive)

explanations tend to be displaced in favor of ap-

peal to efficient causes that are themselves a part

of nature. As the various sciences developed, the

web of explanations they offer has expanded and

become increasingly integrated in interlocking

structures of natural law. At the same time, the sci-

ences have progressively eliminated from their the-

ories the remaining elements of explicit theological

explanation that reflect the close historic associa-

tion of science and religion. A paradigm here, per-

haps, is the transition from Isaac Newton (1642–

1727) to Pierre-Simon Laplace (1749–1827). New-

ton’s calculations indicated that there would be ac-

cumulating errors in the orbits of the planets. This,

he suggested, is corrected by God, who intervenes

periodically to set the solar system aright. A hun-

dred years later, Laplace demonstrated that these

variations in orbital speed are part of a mathemat-

ically predictable cycle, and it is said that when he

was asked about the role of God in his physics, he

triumphantly replied that he had “no need of that

hypothesis.” The sciences, it appears, can get along

perfectly well without appealing to God as a ele-

ment in their account of the world. Theologians

have had to grapple, therefore, with questions

about the relation between the traditional affirma-

tion that God acts in the world and scientific ac-

counts of that world as an intelligible natural order.

How do God’s purposes engage a world whose

history develops within a finely woven skein of

natural law?

Creation as God’s fundamental act

At the heart of virtually any theological account of

divine action will be some understanding of God’s

fundamental activity as creator. Creation has been

construed in various ways in the history of the the-

istic religions, but one particularly prominent view

LetterD.qxd 3/18/03 1:05 PM Page 219

DIVINE ACTION

— 220—

has understood creation as a free and intentional

divine act that calls the world into being and con-

tinuously sustains its existence. There are four ele-

ments in this account. First, creation is a free divine

act in the sense that it does not follow necessarily

from the divine nature; God could exist without

the world in undiminished fullness of being. God

chooses to create not because God must have the

creature, but because it is good for the creature to

be. The act of creation, therefore, is an expression

of generosity and love. Second, creation is an in-

tentional action insofar as God brings the world

into existence knowingly and purposefully. These

first two claims distinguish classical accounts of

creation from emanationist accounts, such as that

of the neo-platonic philosopher Plotinus (205–270

C.E), according to which the perfection of being in

God necessarily overflows into a progression of di-

minishing forms of existence. Third, perhaps the

most striking feature of this theological view is that

God’s creative act accounts for the very being of

the creature. There is no pre-existing unformed

“stuff” that constrains and shapes God’s creative

choice. God creates from nothing (ex nihilo), that

is, apart from God’s creative act, nothing at all

would exist other than God. Finally, the world that

God creates has no power to continue to exist on

its own. Finite things depend at every moment on

a divine creative action that continuously sustains,

or conserves, their existence. Creation, therefore, is

not a one-time event completed at some moment

long ago but rather is an ongoing active relation-

ship of God to the whole finite world throughout

its history. This stands in contrast to the view asso-

ciated with eighteenth century deism, which re-

sponded to the rise of Newtonian mechanics by ar-

guing that the creator establishes the structure of

the world and then leaves it to exist and to oper-

ate on its own.

This way of thinking about God’s action at the

foundation of the world will pervasively shape

one’s interpretation of traditional talk about God’s

action within its history. On this account of cre-

ation, every event in the world depends upon the

action of God; it will be true to say that God acts

in all things. Theologians have not wanted to con-

clude from this, however, that God is the only ef-

fective cause or agent, or that created causes

merely appear to bring about effects in the world

while God alone directly produces all change.

Views of this sort came to be called occasionalism,

because they regard created causes merely as oc-

casions for the action of God in bringing about the

effect. In rejecting this view, Thomas Aquinas (c.

1225–1274) affirmed that God gives created things

active and passive causal powers of their own, that

is, the capacity to affect other things and to be af-

fected by them. God is always the primary cause

who directly sustains the existence of every crea-

ture, but God also chooses to act indirectly

through the operation of created, or secondary,

causes. This provides a further sense in which

events in the world may be understood as God’s

acts, namely, that God acts by means of the order

of nature to produce effects in the world. This

mode of divine action is analogous to indirect

human action in which various means are used to

achieve one’s ends. Aquinas notes that when the

artisan uses a hammer and chisel to shape stone,

the effect is produced both by the tools and by the

human agent who wields them, though the two

causes operate on different levels. Similarly, God

acts by means of the entire network of causal rela-

tions that constitutes the created world. God’s en-

gagement with finite causes goes much deeper, of

course, than the involvement of human agents

with the tools they use. For God directly sustains

the very existence of the finite cause (traditionally

called divine conservation) and, on some accounts,

empowers it to act as it does (traditionally called

divine concurrence). Hence, by establishing the

lawful structures of nature and setting the bound-

ary conditions under which they operate, God in-

directly produces the vast range of effects that to-

gether make up the history of the universe.

Indeed, if the universe were a causally closed, de-

terministic system, then everything that happens

would be an indirect act of God. On the other

hand, if the universe includes moments of indeter-

ministic openness within its structure (e.g., either

as chance or as self-determining freedom), then

God will set the direction of cosmic history but not

necessarily specify all of its details.

The classical conception of creation that un-

derlies this account of divine action is by no means

the only view found in the theistic traditions. Proc-

ess, or neo-classical, theologies reflect a contem-

porary alternative approach that has different im-

plications for divine action in the world. These

theologians make use in various ways of the

thought of Alfred North Whitehead (1861–1947)

and Charles Hartshorne (1897–2000). Within

LetterD.qxd 3/18/03 1:05 PM Page 220

DIVINE ACTION

— 221—

Whitehead’s metaphysical scheme, every entity,

from the simplest elements of the physical world to

God, is a creative synthesis of relations to others.

God is not the absolute source of the world’s exis-

tence, rather God and the world together consti-

tute the basic structure of reality, which is a proc-

ess of creative becoming. God plays a central role,

however, in the world’s unfolding history, for God

makes a crucial contribution to the direction of

each entity’s development and God embraces that

individual’s achievement within the ongoing divine

experience. On this view, God acts in every event

to lure and persuade, and though God’s power is

limited, the reach of God’s influence is not. Charles

Hartshorne explores similar ideas about the inher-

ently social nature and persuasive power of God,

but develops them through the analogy of divine

embodiment in the world. God and world form an

organic unity of many distinct sub-centers of activ-

ity; God shares the experience of all the parts and

acts through them with an immediacy analogous to

(but even more profound than) that with which

humans act through their bodies. Once again,

God’s powers of action are limited by the given

structure of the divine life as a social organism and

by the partial independence and self-creativity of

the constituents that are united in this structure.

One of the strengths of this approach, however, is

that it provides a vivid expression of God’s univer-

sal responsiveness and preeminent influence in

shaping the destiny of the cosmos.

Particular divine action

The theistic traditions have affirmed not only that

God shapes the overall direction of cosmic history

through the act of creation, but also that God acts

in particular events to advance the divine purposes

for the world. The mighty acts of God related in

the biblical stories provide paradigmatic examples

of this form of divine action. Modern theologians

have struggled to know what to say about particu-

lar divine action. There are at least three senses in

which specific events might be singled out as acts

of God in a special way. First, an event may be dis-

tinguished from others by virtue of its disclosive, or

revelatory, importance. Particular events may be-

come the occasion through which individuals and

communities recognize with special clarity the

presence and purposes of God. It need not be the

case that God acts in these events in a way that is

different from God’s universal action in every

event. What marks them out as special is not a dis-

tinctive mode of divine action within them but

rather their power to reveal and exemplify the di-

rection of God’s work in history. If, for example,

the escape of the Hebrew people across the shal-

lows of the Red Sea involved only the ordinary

processes of nature coupled with free human de-

cisions, this event may reveal for this community

God’s liberating purposes. Second, an event may

be distinguished from others by virtue of its causal

role in advancing God’s purposes in the world.

Once again, the event need not be brought about

by God in any distinctive way; one can suppose

that God acts in this special event in just the way

God acts everywhere, namely (on the classical ac-

count) as the creator and sustainer of a system of

natural causes and free human agents. Yet this

event may in fact mark a turning point in the

progress of God’s purposes in history. The escape

of Hebrew people, according to this view, not only

discloses God’s intentions to humankind, it also

advances God’s intentions in a particularly signifi-

cant way. Third, an event may be distinguished

from others because God acts directly in it to turn

events in a direction they would not otherwise

have gone. What makes the event special is that

God acts, on this occasion, to alter the course of

the world’s history. On this view, God not only

acts indirectly through created causes and agents,

God also acts directly in the world to bring about

particular states of affairs. An event of this sort may

or may not evoke a recognition of God’s working,

and it may or may not represent an especially sig-

nificant turning point in the course of events, but

even if it remains hidden in the minutia of history,

it constitutes a particular divine action in the world.

Many modern theologians have sought to

avoid this third, and strongest, claim about divine

action and have interpreted traditional talk about

God’s acts in history exclusively in terms of the first

two. This treats particular divine action as a subset

of God’s universal activity as creator; it incorpo-

rates the idea of divine providence entirely into

the doctrine of creation. At the founding of mod-

ern Protestant theology, for example, Friedrich

Schleiermacher (1768–1834) contended that God

bears the same relation to every event, though

some events play a special role in awakening in

human beings a deepened experience of their ab-

solute dependence upon God as the source of all

things. This approach has important implications

LetterD.qxd 3/18/03 1:05 PM Page 221

DIVINE ACTION

— 222—

for a number of central topics in Christian theology

(e.g., in giving an account of the person and work

of Christ), and is a matter of controversy. There are

powerful considerations that push in this direction,

however, not the least of which are those derived

from the impact of the natural sciences.

It has become commonplace for modern the-

ologians to argue that a scientifically informed un-

derstanding of the world presents fatal objections

to the assertion that God acts in history to affect

the course of events. Rudolph Bultmann

(1884–1976), for example, contended that one can-

not embrace a scientific world view and also affirm

that God acts within objective history. The lawful

structures described by the sciences leave, in Bult-

mann’s phrase, “no room for God’s working,” and

any divine action will necessarily be a miraculous

intervention that disrupts the natural order. Similar

claims have been made by a succession of con-

temporary theologians. Bultmann’s solution was to

insist that God’s action should be understood as an

engagement with the human self that leaves the

natural order untouched. This strategy can suc-

ceed, of course, only if one thinks that selves can

be affected without altering their physical condi-

tions, and if this idea is rejected, then it is far from

clear that God can interact with embodied persons

without affecting the natural world.

There are at least two considerations at work in

these scientifically based worries about particular

divine action. Both have to do with miracles, un-

derstood in the rather artificial but familiar modern

sense of divine actions that contravene the struc-

tures of nature. The first concerns the epistemic

status of claims about miracles. Although it is some-

times said that science has shown that miracles

cannot occur, there is little prospect of vindicating

this general claim. It is more plausible to note that

scientifically literate people find their expectations

about the world to have been shaped in ways that

raise significant evidential barriers to accepting

claims about miracles. David Hume (1711–1776)

gave early and elegant expression to an argument

that it will always be more reasonable to conclude

that testimony about miracles is mistaken or fraud-

ulent than to believe that a well-evidenced law of

nature has been abrogated. There are also distinc-

tively theological objections to giving miracles a

pervasive role in one’s account of divine action.

Nonetheless, while there are good reasons for cau-

tion about claims regarding miracles, it important

to note that, at least on a classical account of cre-

ation, there is no theological ground for denying

that the creator of the universe is free to act in ways

that exceed the causal powers of creatures.

The second issue concerns the claim that any

divine action that affects the course of events will

necessarily constitute a miraculous intervention in

the lawful structures of nature. This conclusion

may appear inevitable if one thinks of the natural

order as a deterministic system; it appears that in a

closed structure of sufficient finite causes, God can

act either by determining the design of the struc-

ture in the initial act of creation or by miraculously

intervening within it. In the modern discussion of

divine action it has often been assumed that uni-

versal causal determinism has been endorsed by

the natural sciences, either as result of its investi-

gations or as a presupposition of its methods.

There are good reasons not to embrace this con-

clusion, however. Determinism has neither been

established nor refuted by the sciences to date;

rather, it represents a metaphysical view that ex-

trapolates beyond the findings of the sciences and

that need not be assumed in scientific research.

A number of theologians have sought ways to

conceive of particular divine actions that do not in-

volve any disruption of the structures of nature.

Arthur Peacocke (1924– ) notes that the world de-

scribed by the natural sciences is structured as a

complex, nested hierarchy of causal systems; for

example, biochemical processes operate within a

cell located within an organ that functions within

an organism. The higher levels of organization

constrain the operation of their parts without abro-

gating the causal laws proper to those parts. Pea-

cocke couples this picture of the natural order with

a panentheistic conception of God according to

which the world is encompassed within God, and

God constitutes the ultimate whole that unites all

finite systems. This opens the way to proposing

whole-part as the model for God’s action; God af-

fects the world as a higher level system affects is

parts, channeling their operation in particular ways

without violating the lawful structures that govern

them. Note that this account would allow for non-

miraculous particular divine influences upon the

course of events whether or not the world consti-

tutes a closed system of sufficient (i.e., determinis-

tic) causes. The crucial task facing such a position

is to vindicate the claim that God can affect the op-

erations of finite causal systems without this divine

LetterD.qxd 3/18/03 1:05 PM Page 222

DIVINE ACTION

— 223—

influence registering as a discontinuity in the

causal series.

Another strategy in developing an account of

particular divine action explores the theological

possibilities that arise if the universe is not in fact

thoroughly deterministic in its structure. If the

order of nature does not constitute a lock step of

deterministic law but rather includes elements of

under-determination, whether as mere chance or

as self-determining freedom, then perhaps God

can act in the world without in any way disrupting

its inherent structures. The world that God created

might, that is, incorporate both lawful regularities

and openness to novel developments that are not

entirely prescribed by the past.

John Polkinghorne (1930– ) has proposed that

the science of chaotic systems, which are highly

sensitive to initial conditions and functionally un-

predictable, provides a window on what may be a

more supple and flexible network of relations in

nature. Although these systems are described in

deterministic equations, Polkinghorne notes that

the laws of nature formulated by the sciences are

a simplification and abstraction from the actual

complexities of nature. This suggests that God

might act by affecting the conditioning context

within which these malleable systems operate.

Other thinkers have explored the possibilities cre-

ated by indeterministic interpretations of quantum

mechanics. William Pollard (1911– ) was the first to

develop a proposal of this kind, but the idea has

been explored and refined by a number of others.

On what is arguably the dominant (though by no

means the only) interpretation of quantum me-

chanics, there are transitions in quantum systems

(namely, from a probabilistically described super-

position of states to a determinate value for a

measured variable) that have necessary but not

sufficient conditions in preceding states. If the ef-

fects of these chance transitions are sometimes am-

plified by the larger systems in which they occur,

then they can make a difference in the macro-

scopic course of events. Robert John Russell

(1946– ) has argued that this amplification can be

found in a number of natural structures, notably in

genetics. The structures of nature, in this case,

would be open and flexible in such a way that

God could, without disrupting the probabilistic

regularity of those structures, act through them to

bring about particular effects in the world. It might

be objected that this represents a return to the

God-of-the-Gaps, that is, the hasty appeal to divine

action at points of scientific ignorance. In this case,

however, the relevant gaps occur in nature, not

simply in human knowledge of nature. If the

Copenhagen Interpretation of quantum theory is

correct, then the deepest structures in nature are

indeterministically open, and that is a fact about

the world that theological reflection will need to

take into account. Of course, the viability of par-

ticular theological proposals of this sort will de-

pend in part on developments in the relevant sci-

ences. Given the multiple options in interpreting

quantum theory and the persistence of unresolved

fundamental questions within the theory itself, any

theological use of this science must remain a ten-

tative exploration of intriguing possibilities.

Conclusion

The affirmation that God acts in the world has

played a central role in the theistic religious tradi-

tions, and there are a number of ways in which

this idea can be understood. God acts as the cre-

ator who calls all finite things into being and sus-

tains their existence at every moment. In this way

God acts directly with every causal operation or in-

tentional action of creatures. By virtue of endow-

ing created things with causal powers of their own,

God can be also understood to act indirectly by

means of the order of nature. Theists have typically

affirmed that particular events can be identified as

special acts of God, at least in the sense that they

play a distinctive epistemic or causal role, and per-

haps also in the sense that they reflect a direct di-

vine action that affects the course of events or the

lives of individuals. The latter form of special di-

vine action raises difficult questions of theological

interpretation, and it presents one of the points at

which the dialogue between religion and science

has been most fascinating and fruitful.

See also CLOCKWORK UNIVERSE; COPENHAGEN

INTERPRETATION; CREATIO EX NIHILO; DEISM;

ETERMINISM; DOUBLE AGENCY; GOD OF THE

GAPS; MIRACLE; PANENTHEISM; PROCESS THOUGHT;

ROVIDENCE; SPECIAL DIVINE ACTION; SPECIAL

PROVIDENCE; THEISM; WHITEHEAD, ALFRED NORTH

Bibliography

Aquinas, Thomas. Summa Theologiae (1266–1273), Ia,

QQ. 22–23, 103–05, ed. Timothy McDermott. London:

Blackfriars, 1964.

LetterD.qxd 3/18/03 1:05 PM Page 223

DNA

— 224—

Barth, Karl. Church Dogmatics (1935), Vol. 3, Part 3: Doc-

trine of Creation, the Creator, His Creature, eds. G.

W. Bromiley and T. F. Torrence. Edinburgh, UK: T&T

Clark, 1977.

Bultmann, Rudolph. Jesus Christ and Mythology. New

York: Scribner, 1958.

Burrell, David. Aquinas: God and Action. Notre Dame,

Ind.: University of Notre Dame Press, 1979.

Calvin, John. Institutes of the Christian Religion

(1535–1559), Vols. 1 and 2, ed. John T. McNeill.

Louisville, Ky.: Westminster John Knox Press,

1960.

Gilkey, Langdon. “Cosmology, Ontology, and the Travail

of Biblical Language.” Journal of Religion 41 (1961):

194–205.

Gilkey, Landgon. Reaping the Whirlwind: A Christian In-

terpretation of History. New York: Seabury Press, 1981.

Hartshorne, Charles. Man’s Vision of God and the Logic of

Theism. Hamden, Conn.: Archon Books, 1964.

Hume, David. “On Miracles” In An Enquiry Concerning

Human Understanding (1748), Section 10. The

Clarendon Edition of the Works of David Hume, ed.

Thomas L. Beauchamp. New York: Oxford University

Press, 2001.

Kaufman, Gordon. God the Problem. Cambridge, Mass.:

Harvard University Press, 1972.

Morris, Thomas V., ed. Divine and Human Action: Essays

in the Metaphysics of Theism. Ithaca, N.Y.: Cornell

University Press, 1988.

Peacocke, Arthur. Theology for a Scientific Age: Being and

Becoming, Natural and Divine. Oxford: Basil Black-

well, 1990.

Polkinghorne, John. Science and Providence: God’s Inter-

action with the World. London: SPCK Press, 1989.

Pollard, William. Chance and Providence: God’s Action in

a World Governed by Scientific Law. New York: Scrib-

ners, 1958.

Russell, Robert John; Murphy, Nancey; Isham, C.J., eds.

Quantum Cosmology and the Laws of Nature: Scien-

tific Perspectives on Divine Action, rev. edition. Vati-

can City State: Vatican Observatory Publications, 1996.

Russell, Robert John; Murphy, Nancey; Peacocke, Arthur,

eds. Chaos and Complexity: Scientific Perspectives on

Divine Action. Vatican City State: Vatican Observatory

Publications, 1995.

Russell, Robert John; Stoeger, William; Ayala, Francisco J.,

eds. Evolutionary and Molecular Biology: Scientific

Perspectives on Divine Action. Vatican City State: Vati-

can Observatory Publications, 1998.

Russell, Robert John; Murphy, Nancey; Meyering, Theo C.;

Arbib, Michael A., eds. Neuroscience and the Person:

Scientific Perspectives on Divine Action. Vatican City

State: Vatican Observatory Publications, 1999.

Russell, Robert John; Clayton, Philip; Wegter-McNelly,

Kirk; Polkinghorne, John, eds. Quantum Mechanics:

Scientific Perspectives on Divine Action. Vatican City

State: Vatican Observatory Publications, 2001.

Schleiermacher, Friedrich. The Christian Faith

(1830–1831), Vols. 1 and 2, trans. H. R. Mackintosh.

Edinburgh, UK: T&T Clark, 2001.

Tanner, Kathryn. God and Creation in Christian Theol-

ogy: Tyranny or Empowerment. London: Basil Black-

well, 1988.

Tracy, Thomas F., ed. The God Who Acts: Philosophical

and Theological Explorations. University Park: Penn-

sylvania State University Press, 1995.

Ward, Keith. Divine Action. London: Collins, 1990.

Whitehead, Alfred North. Process and Reality: An Essay in

Cosmology. New York: Macmillan, 1929.

Wiles, Maurice. God’s Action in the World: The Bampton

Lectures for 1986. London: SCM, 1986.

Wright, G. Ernest, and Fuller, Reginald H. The Book of the

Acts of God. Garden City, N.Y.: Doubleday, 1957.

THOMAS F. TRACY

DNA

DNA (deoxyribonucleic acid) carries design infor-

mation between generations, and thus accounts for

inherited biological traits (phenotypes). At concep-

tion, a father’s sperm injects a set of DNA mole-

cules into a mother’s egg, which already contains a

nearly matching set. Those molecules contain the

designs for all the material components their child

needs for growth, development, and daily living.

Structure of DNA

The designs are called genes. Some genes play a

role in regulating other genes, and some design ri-

bonucleic acid, a close relative of DNA. But

mostly, the designs in DNA are for the class of

LetterD.qxd 3/18/03 1:05 PM Page 224

DNA

— 225—

chemicals called proteins. The human body con-

tains tens of thousands of kinds of proteins, which

do all the body’s work. Interactions among those

proteins, and interactions between them and envi-

ronmental factors account for the processes and

structures of the body. Those processes and struc-

tures are manifested as inherited traits. DNA is

comprised of chains of chemical subunits called

nucleotides, each of which contains one nitroge-

nous base: adenine (A), thymine (T), cytosine (C),

or guanine (G). The design instructions in DNA

are spelled out as particular sequences of these

four bases. This is analogous to conveying instruc-

tions in printed books by particular arrangements

of the twenty-six letters of the alphabet. In the case

of genes, however, there are only four letters in the

alphabet. Hundreds of nucleotides are linked in a

DNA chain in a sequence that spells out instruc-

tions for a single gene.

There are two complementary chains in the

structure of DNA. Each nucleotide in DNA has a

sugar component joined to a phosphate group

at one point on the sugar, and to a nitrogen-

containing base attached at another point. The

chains in DNA have the phosphate of one nu-

cleotide linked to the sugar of the next nucleotide

to form a strand of alternating sugars and phos-

phates with dangling nitrogenous bases. DNA con-

tains two such chains, twisted around each other

to form a double-stranded helix with the bases on

the inside. Every A on one chain forms weak

bonds with a T on the other strand, and every C on

a strand bonds weakly to a G on the opposite

chain. The two strands, held together weakly by

the pairing of A with T, and G with C, are thus

complementary, and the sequence in one can be

deduced from the other’s sequence.

Design information is transmitted as new DNA

to new cells during development and growth. The

complementarity of the two DNA strands allows

their information to be copied. Each old strand is

used as a template in synthesizing a new comple-

mentary one. Intricate cellular machinery makes

new copies of the DNA when a fertilized egg di-

vides into two progeny cells. When each of the

progeny divides again, the new progeny all receive

complete copies of the parental DNA. As the fertil-

ized egg grows to become successively an embryo,

a fetus, a child, and finally an adult, cells go

through many rounds of division with replication

of the DNA in each round. Finally, adult humans

have trillions of cells, each one (except sperm and

ovum) containing complete copies of the DNA ini-

tially contributed by the parents.

On rare occasions mutations (changes) are

made in nucleotides by chemicals, radiation, or er-

rors in copying DNA. In a nucleotide chain, one

nucleotide may be substituted for another, or one

or more nucleotides might be inserted or deleted.

Sometimes the change in DNA structure has little

or no effect on the function of the gene’s product,

but it frequently harms the function to some de-

gree, or very rarely enhances it. Harmful mutations

cause gene-based diseases, but enhancing muta-

tions allow organisms to evolve new or more ef-

fective functions. Like normal phenotypes, disease

phenotypes usually require the products of multi-

ple genes, so most defective genes predispose an

organism to disease rather than directly causing it.

The accumulation of mutations within the human

species accounts for such phenotypic differences

as eye color, stature, or skin pigmentation. The

number of mutations among human genes is so

large that no two persons, except for identical

twins, have exactly the same nucleotide sequence

in the three billion bases of their DNA.

Control of gene expression

DNA information is expressed as proteins and their

feedback networks. The information resident in

nucleotide sequences is used not only for replicat-

ing DNA, but also for synthesizing proteins. Pro-

teins are chains of a few hundred subunits called

amino acids, of which there are twenty kinds. The

amino acids in a protein are arranged in a specific

sequence by cellular machinery that translates the

genetic information coded in DNA. The sequence

of nucleotides, read three at a time, corresponds to

the sequence of amino acids in a protein. The

amino acids differ among themselves in chemical

character so that every kind of protein differs in

chemical character from others. For the work of

the human body many thousands of proteins are

needed, each having a highly specific function like

catalyzing a chemical reaction or transporting oxy-

gen. Observable phenotypes are the result of pro-

tein action, usually the coordinated action of many

proteins. The functions of many proteins are inte-

grated into large networks, and these webs of

chemical processes act as feedback control systems

LetterD.qxd 3/18/03 1:05 PM Page 225

DNA

— 226—

allowing organisms to shift the balance of their ac-

tivities to adapt to changes in the demand for the

system’s output. Often the networks possess alter-

nate pathways for achieving a desired output.

Differentiation into specialized cells requires

the control of gene expression. The development

of a human being starts with a single-celled, fertil-

ized egg. As the egg divides into two cells, and as

successive rounds of cell division occur, every

progeny cell receives a complete copy of parental

DNA. In the first few divisions, the cells produced

are identical in all observable characteristics, but as

cell division continues, cells are produced that dif-

fer in phenotype even though all the cells con-

tinue to have identical DNA. In this differentiation,

particular genes are controlled by blocking their

expression, not by changing nucleotide sequence.

Regulatory molecules block particular sites in DNA

preventing translation of the corresponding genes

into their products. Specific blocking thus gener-

ates different patterns of gene expression. Chang-

ing patterns of gene expression produce distinct

populations of cells, diverging in phenotype as dif-

ferentiation progresses. Eventually, differentiation

in humans produces more than two hundred cell

types, organized into different tissues and organs.

In any one cell type the majority of its approxi-

mately 35,000 genes is repressed, leaving a small

subset of expressed genes that differs from the

subsets expressed in other cell types. Phenotypic

differences between progeny in a given cell gener-

ation depend on the location of the cells in differ-

ent microenvironments. During differentiation cells

adapt to a succession of environmental changes

produced by changes in their neighboring cells

and extracellular fluids. Each successive adaptation

is superimposed on its predecessor so that each

terminally differentiated cell manifests the entire

history of its lineage and not merely its immediate

state. Since differentiation is irreversible in animals,

(except in special cases), history as well as DNA

designs a person, even in the material sense.

Feedback networks and regulation of genes

allow individual organisms to adapt to changing

conditions throughout life. When environment in-

creases the need for the product of a network of

chemical reactions, the overall process will be ac-

celerated, and when need decreases the process

will be inhibited. Obviously, adaptation to envi-

ronment is induced by contact with physical and

chemical forces, but adaptation can be evoked

even without physical contact, as in the adaptation

of the brain through learning, and emotional reac-

tion. Many of these adaptive responses affect pat-

terns of gene expression, and therefore environ-

ment, as well as history, joins with DNA in

designing persons.

At the level of populations, long-term adapta-

tion to environment occurs more by changes in

gene structure than by changes in the expression

of genes. The mechanism for this adaptation is the

natural selection that underlies evolution. For ex-

ample, skin pigmentation may be an adaptation

that protects against exposure to the sun, and the

genes that design the pigment systems would be

naturally selected in successive generations that

are exposed to much sunlight. Similarly, sickle-cell

hemoglobin seems to have evolved in Africa be-

cause it offers resistance to malaria that is preva-

lent there.

Long-term adaptation through natural selection

is most obvious in the case of physical and chemi-

cal aspects of human beings. Less obvious is the

adaptation of behaviors through natural selection

of genes, a possibility actively studied under the

title “sociobiology.” Although the mechanisms pro-

ducing material phenotypes may seem more obvi-

ous than those producing social behaviors, a mech-

anism giving rise to a certain behavior may be

thoroughly materialistic, although far more com-

plex. Behavior modification by psychoactive drugs

reveals a material mechanism for behavior. A mech-

anism can be pictured, for example, in the courting

and mating behaviors that are correlated with the

release of hormones from the brain, when an ani-

mal or human senses that a potential mate is near.

Those released hormones induce particular chemi-

cal reactions at many sites throughout the body, giv-

ing rise to an appropriate pattern of bodily actions.

Moreover, feedback responses between the mates

guide further behavioral interactions between them.

The hormonal system that links brain functions to

bodily functions is, of course, designed by genes,

and the mechanism just sketched is clearly materi-

alistic. The frequent association of natural selection

with notions of “survival of the fittest,” makes altru-

ism an especially challenging kind of behavior to

study in testing the validity of sociobiology theory,

and much of the research of sociobiologists is fo-

cused on the evolution of a gene for altruism.

LetterD.qxd 3/18/03 1:05 PM Page 226

DOUBLE AGENCY

— 227—

Genes affect behavior, but as is the case with

most human phenotypes, genes act in combinations

and their expression is modulated by the histories

and environments of individuals, as already de-

scribed. Through the invariability of individual his-

tories and environments, natural selection must be

able to recognize the difference between organisms

that possess a particular behavioral gene, and those

that do not possess it. In order for a behavioral gene

to evolve through natural selection it must be pow-

erful enough in determining the behavior, to avoid

substantial compromise by variable non-genetic

factors. Sociobiology, then, tends to favor a strongly

deterministic and materialistic view of behavior.

Human nature and genetic determinism

Choosing is part of human nature, but its degree of

autonomy is debated. All agree that choice is con-

strained by genes, history, and environment, but

does any degree of freedom remain? Science de-

scribes material brain mechanisms as chains of

causes and effects, but every cause is an effect hav-

ing a prior cause. Since the initial cause is not rec-

ognized by science, some say thought initiation is

due to chance. Others look for initiation outside

the material realm of science by distinguishing be-

tween mind and brain, or even spirit and brain.

Some degree of genetic determinism is neces-

sary in describing human nature. All the possible

scenarios of a person’s life must conform to the de-

signs in DNA, and thus genes set rigid, though spa-

cious boundaries on what a person can be and do.

But genes are insufficient for explaining what ac-

tually happens. What actually happens within the

boundaries set by genes, depends on factors that

control genes, including environment, history, and

mental state. The question arises whether spiritual

forces can be added to the list of controlling fac-

tors. Material determinism argues that a complete

physicochemical description of the history and

state of a person would explain everything without

including a spiritual component. Some, however,

argue that human spirituality is a capacity that

emerged as gene-based human biology evolved,

and that its activity cannot be fully comprehended

at the molecular level. Still others add spirit as a

control factor in human nature in accepting a dual-

ism where body and spirit are distinct, though co-

existent, in a person. The disparity in these views

of human nature has theological consequences.

A view of human nature according to material

determinism fits atheism and deism. It provides no

locus for personal interaction with God, although

deists might suppose that God influences humans

through environment. Belief in human spirituality,

either as an emerged capacity or as a distinct part

of human nature does provide such a locus. Scien-

tific understanding of gene-based human biology

does not perceive a spiritual component in human

nature, but it might not be expected that a physico-

chemico-molecular description of humans would

be capable of such discernment in the first place.

See also GENE PATENTING; GENETIC DEFECT; GENETIC

DETERMINISM; GENETICS; HUMAN GENOME

PROJECT; MUTATION; NATURE VERSUS NURTURE

Bibliography

Avise, John C. “Evolving Genomic Metaphors: A New Look

at the Language of DNA.” Science 294 (2001): 86-87.

Barbour, Ian. Religion in an Age of Science. New York:

Harper Collins, 1990.

Dawkins, Richard. The Selfish Gene. Oxford: Oxford Uni-

versity Press, 1989.

Dennis, Carina; Gallagher, Richard; and Campbell, Philip,

eds. “The Human Genome.” Nature 409 (2001): 813-

958.

Edelman, Gerald M. Bright Air, Brilliant Fire: On the Mat-

ter of the Mind. New York: Basic Books, 1992.

Goldsmith, Timothy H. The Biological Roots of Human

Nature: Forging Links Between Evolution and Behav-

ior. New York: Oxford University Press, 1991.

Hefner, Philip. “Determinism, Freedom, and Moral Fail-

ure.” In Genetics: Issues of Social Justice, ed. Ted Pe-

ters. Cleveland, Ohio: Pilgrim Press, 1998.

Kitcher, Philip. The Lives to Come: The Genetic Revolution

and Human Possibilities. New York: Simon and

Schuster, 1996.

Kotulak, Ronald. Inside the Brain: Revolutionary Discover-

ies of How the Mind Works. Kansas City, Mo.: An-

drews McMeel, 1996.

Peters, Ted. “Genes, Theology, and Social Ethics.” In Ge-

netics: Issues of Social Justice, ed. Ted Peters. Cleve-

land, Ohio: Pilgrim Press, 1998.

Raven, Peter H., and Johnson, George B. Biology, 6th edi-

tion. New York: McGraw Hill, 2002.

Stevens, Raymond C.; Shigeyuki, Yokoyama; and Wilson,

Ian A. “Global Efforts in Structural Genomics.” Sci-

ence 294 (2001): 89-92.

LetterD.qxd 3/18/03 1:05 PM Page 227

DOWNWARD CAUSATION

— 228—

Wilson, Edward O. Sociobiology: The New Synthesis. Cam-

bridge, Mass.: Harvard University Press, 1975.

R. DAVID COLE

DOUBLE AGENCY

The idea of double agency arises in discussions of

divine action through the operation of finite causes

and the actions of human agents. Thomas Aquinas

(c. 1225–1274) contended that God as creator is

the first, or primary, cause who gives being to fi-

nite things and empowers them to act as they do.

As a result, the activity of creatures is also the ac-

tion of God, though God and creatures act on dif-

ferent levels. Claims about double agency raise

particularly difficult issues when considering God’s

relation to free human actions. Here one must

grapple with questions about whether and in what

sense the act can simultaneously be ascribed to

more than one agent.

See also DIVINE ACTION; PROVIDENCE; THOMAS

AQUINAS

Bibliography

Aquinas, Thomas. Summa Theologiae (1266–1273), Ia,

QQ. 22-23, 103-05, ed. Timothy McDermott. London:

Blackfriars, 1964.

Farrer, Austin. Faith and Speculation. London: A. & C.

Black; New York: New York University Press, 1967.

THOMAS F. TRACY

DOWNWARD CAUSATION

When the direction of casual influence extends

from “higher” levels of reality (say, above the level

of physics) down to “lower” levels of reality, it is

called downward causation. The ontological struc-

ture of the world may be seen as consisting of

more than one domain, with each domain consist-

ing of different entities, and with different proper-

ties defined over the respective domains. Thus

Cartesian dualism envisaged a bifurcated world of

two metaphysically independent domains, one

containing mental substances defined by “thought”

or “consciousness,” and the other containing phys-

ical “stuff” defined by “extension.” In contempo-

rary emergentism the world is pictured in terms of

a multilayered structure, with microphysical enti-

ties at the bottom and with higher-level entities

(such as molecules, cells, organisms, and social

groups) being mereologically composed of these

lower-level entities, yet characterized by a set of

properties distinctive of the relevant higher level.

In a way, so-called nonreductive physicalism,

which more or less became the received view in

the philosophy of mind of the last quarter of the

twentieth century, may be seen as nothing but a

modern application of classical emergentism

within the philosophy of mind. Although it holds

that, ontologically speaking, all there is are physi-

cal entities and mereological aggregates thereof, it

argues that psychological properties are irreducibly

distinct from the underlying physical and biologi-

cal properties.

Regarding such stratified ontologies, two ques-

tions naturally arise. First, there is the question of

whether higher-level processes may causally inter-

act amongst each other. Secondly, there is the

closely related question of whether higher-level

processes may also exert “downward” causal influ-

ence on events occurring at lower-levels of reality.

Indeed, this so-called downward (or top-down)

causation may hold special interest from a theo-

logical perspective, since the very possibility of di-

vine action may plausibly be seen as dependent on

the possibility of downward causation. It has been

argued that the first question inherits whatever

problems may attach to the second, which is the

more crucial of the two. Thus Jaegwon Kim has

claimed that same-level causation can occur only if

cross-level causation can occur. Accordingly, down-

ward causation is essential to most of the stratified

ontologies under consideration.

The concept of downward causation allegedly

runs into serious difficulties. Specifically, there are

problematic implications of the idea implied in

downward causation; for example, that higher-

level processes, once having emerged from lower-

level physical processes, biological processes, and

so on, would somehow take on a causal life of

their own down to the point of actually interfering

in the underlying chain of physical causes and

events. If, say, emergent mental properties are ir-

reducibly distinct from physical properties (as

maintained in emergentism and non-reductive

LetterD.qxd 3/18/03 1:05 PM Page 228