Jacques Maritain Center: Thomistic Institute

Top Down, Bottom Up or Inside Out?
Retrieving Aristotelian Causality in Contemporary Science

Michael J. Dodds, OP
July 25, 1997

Ever since the time of Thales (d.546 B.C), philosophers and scientists have wondered about the ultimate stuff of the universe. What are all the things we see around us really, ultimately, fundamentally -- down deep? Thales saw water as the fundamental principle of all things. Other pre-Socratic philosophers chose air or fire. The Greek atomists believed the universe was composed of indivisible atoms of matter, a notion later resurrected in classical Newtonian physics. Contemporary science would probably look to mass-energy or perhaps the murky indeterminacies of quantum mechanics.

The common intuition behind all such thinking is that to find the real nature of things, one must break them down into their fundamental components. Real understanding begins only when one gets to the bottom of things, and somehow the things at the bottom explain everything else all the way up.

This "bottom up" thinking became the creed of modern science. The method of understanding things by breaking them down to their basic components became a metaphysics -- a conviction that the most basic stuff of the universe is also the most real and that the rules that govern its behavior can ultimately explain everything else. The method of reduction became the metaphysics of reductionism.

This philosophical view has been challenged in this century by discoveries coming from within science itself. In physics, chemistry and biology there is a growing conviction that characteristic activities of whole entities or systems in nature cannot be explained by the behavior of their parts. New properties emerge in the whole that are not found in the part, and in some cases the behavior of the part, far from explaining the whole, can itself be accounted for only in reference to the whole. This "top down" thinking is now seen by many as a necessary complement to the "bottom up" approach of modern science.

In this paper, I will briefly review these "bottom up" and "top down" ways of thinking. I will then argue that top down thinking is itself liable to "bottom out,"-- to slide into reductionism -- unless it can show that the "wholes" of which it speaks are anything more than conglomerations of parts. Finally, I will suggest that the Aristotelian understanding of substantial form can provide an ontological foundation for the whole, explaining its causality not from "bottom up" or "top down" but from "inside out."

2. Causality from the bottom up

Bottom up thinking in contemporary science may have it remote roots in the Greek quest for the ultimate stuff of the universe, but it finds its more immediate inspiration in Galileo's scientific method. This method first breaks down a phenomenon into simple parts that can be represented mathematically, then makes certain predictions from those representations, and finally verifies the predictions by experiment.(1) Through its enormous success in all branches of science, it has vindicated the thoroughgoing bottom up approach of reductionism, reinforcing both the epistemological notion that a whole can best be understood or explained through an analysis of its parts and the ontological idea that the part is somehow more fundamental or "real" than the whole.(2)

Epistemologically, reductionism involves "the explanation of a theory or a set of experimental laws established in one area of inquiry, by a theory ... formulated for some other domain."(3) This practice has been quite successful in some areas of science. The description of light in traditional optics, for instance, has been reduced to electromagnetism.(4) In other areas, however, reductionism remains controversial. As Evandro Agazzi points out:

In the case of other reductions..., the thesis of epistemological reductionism becomes more and more problematic and even false (reduction of chemistry to physics, or biology to chemistry, of psychology to biology, etc.). For example, despite all the progress of molecular biology and biochemistry, one is not in a position to remedy the absence of biological concepts in the vocabulary of chemistry, nor to give truly exhaustive definitions of the fundamental biological notions in chemical terms, which is preliminary to every enterprise which could translate all true biological propositions in as many theorems of chemistry.(5)

Understood ontologically, reductionism ceases to be a methodological tool and becomes a metaphysical claim about reality. The fundamental components of a thing (or of the universe) are considered most real and are thought to explain everything else. Other aspects of things must be excluded from the realm of "what really exists."(6)

If the ultimate reality is atoms and void, for instance, then qualities such as color and taste become merely subjective experiences. We can find this notion already in Democritus, the Greek atomist who maintained: "by convention color exists, by convention bitter, by convention sweet, but in reality atoms and void."(7) Centuries later, Galileo arrived at the same conclusion that matter is really "infinitely small indivisible atoms," and likewise questioned the objective reality of sense qualities: "But that external bodies, to excite in us these tastes, these odors, and these sounds, demanded other than size, figure, number, and slow or rapid motions, I do not believe."(8) Taken to its logical conclusion, ontological reductionism maintains that the ultimate stuff of the universe alone is real and its properties explain everything else.

To know the truth about the ultimate stuff of the universe is to know the fundamental secret of creation. According to Ian Stewart and Jack Cohen, this as the promise of a "Theory of Everything" in the mind of popular science:

The philosophy involved in such a concept of explanation is called reductionism... The rules on a given level of explanation are all consequences -- at least to some useful degree of approximation -- of those on lower levels. Deeper levels are more fundamental, and if a Theory of Everything exists, it lies at the deepest level of all. In an extreme but common view, it is not just a useful approximation to the truth: it is the truth."(9)

This is reminiscent of Stephen Hawking's provocative suggestion that a Theory of Everything might be the first step in discovering "why it is that we and the universe exist," and so coming to "know the mind of God."(10)

3. Causality from the top down

Reductionism promises a great deal, but its promises have been seriously challenged by recent discoveries in science. These suggest that, though reductionism is a useful tool, it is a limited tool which must be complemented by a more holistic or "top down" view of everything from atoms to organisms.

3.1. Physics

We might begin with discoveries in physics. To account for the many subatomic particles that physicists were discovering, it was proposed in 1963 that such particles were composed of even smaller particles called "quarks." This greatly simplified particle physics, since there were only a few types of quarks (classified by "flavor" and "color"). But, as Ian Barbour explains, it also left physicists with a rather unusual component part:

[Q]uarks are a strange type of 'component': free quarks have never been observed, and it appears that a quark cannot exist alone, according to the theory of quark confinement. A proton is made up of three quarks, for example, but if you try to separate them you need a great deal of energy and you end by creating more quarks, which combine with the ones you already had to make new protons and other particles. Quarks are parts that apparently cannot exist except in a larger whole.(11)

Quantum theory required physicists to think of the atom as a whole, not a conglomeration of parts:

In quantum theory the atom must be represented as a whole rather than as a collection of parts. Consider the helium atom, composed of two protons and two neutrons (in its nucleus) and two orbital electrons. In the "planetary model" it was pictured as a nucleus around which circled two separate identifiable electrons; the atom's parts were clearly distinguishable, and the laws of its total behavior were derivable from analysis of the behavior of these components. But in quantum theory the helium atom is a total pattern with no distinguishable parts. Its wave function is not at all the sum of two separate single-electron wave functions. The electrons have lost their individuality; we do not have electron A and electron B, but simply a two-electron pattern in which all separate identity is lost.(12)

Not only is the part unable to explain the behavior of the whole in contemporary physics; it is now the whole that explains the behavior of the part. William Wallace illustrates this using the Bohr model of the sodium atom. The atom is composed of a nucleus of twelve neutrons and eleven protons and has eleven orbital electrons, but none of these acts independently. Each acts only as a part of the whole, following laws that apply to the whole, such as Bohr's quantum rules and the Pauli exclusion principle. A "free" electron, for instance, will act only according to its own mass and electric charge, but an electron that is "bound" within the sodium atom "'obeys' Bohr's quantum rules -- not falling into the nucleus or radiating when in its assigned orbit, making only its 'allowed' transitions." The bound electron also follows the Pauli exclusion principle. This principle considers the atom as a whole and specifies that within the atom no two electrons can have the same state (specified by the four quantum numbers that describe energy, angular momentum, orientation and spin). Although "on its own, each electron would be indifferent to the particular energy state it might occupy within the atom, within the atom, according to the Pauli exclusion principle, each electron is assigned to a unique state occupied by no other."(13)

Ian Barbour argues that a bound electron is best described not as an individual particle but as the state of a system.

A bound electron in an atom has to be considered as a state of the whole atom rather than as a separate entity. ... In quantum reasoning any attempt to describe the behavior of the constituent electrons is simply abandoned: the properties of the atom as a whole are analyzed by new laws unrelated to those governing its separate "parts," which have now lost their identity.(14)

Henry Margenau agrees that the laws which govern electrons in an atomic whole are different from those that govern them in isolation:

It is as though here, for the first time, physics had discovered within its own precincts a purely social law, a law that is simple in its basic formulation and yet immense in its collective effects. Mechanistic reasoning, already far behind, has gone out of sight as a result of this latest advance... In the Pauli principle is a way of understanding why entities show in their togetherness laws of behavior different from the laws which govern them in isolation. The emergence of new properties on composition is a rather general phenomenon in modern physics and owes its occurrence to the exclusion principle.(15)

The new properties that emerge as atoms combine cannot be explained by the parts:

As more complex systems are built up, new properties appear that were not foreshadowed in the parts alone. New wholes have distinctive principles of organization as systems and therefore exhibit properties and activities not found in their components.(16)

3.2. Chemistry

If new wholes with new properties can arise in the science of physics, they are all the more common in chemistry. Here again, what was valid regarding a simple object is often "no longer...valid when one passes to the consideration of a complex system." We might think of the distinction between chemical "mixtures" and "compounds." Each part of a mixture, "retains all of its properties, and the properties of the mixture are in a certain manner the sum or the 'resultant' of the properties of the constituents." In a compound, however, there seems to be a new "thing" with completely new properties. Water, for instance, "possesses different properties from those of hydrogen and oxygen."(17)

3.3. Biology

With the discovery of the structure of the DNA molecule by James Watson and Francis Crick in 1953, some thought it would be possible to reduce biology to chemistry and chemistry to physics. Crick himself considered this the fundamental work of biology:

The ultimate aim of the modern movement in biology is in fact to explain all biology in terms of physics and chemistry. ... Eventually one may hope to have the whole of biology "explained" in terms of the level below it, and so on right down to the atomic level.(18)

While the chemical study of biological phenomena has proved enormously fruitful, it does seem not that biology can be reduced to chemistry either in practice or in principle. Mario Bunge explains:

At first sight, the discovery that the genetic material is composed of DNA molecules proves that genetics has been reduced to chemistry. However chemistry only accounts for DNA chemistry: it tells us nothing about the biological functions of DNA -- e.g., that it controls morphogenesis and protein synthesis. In other words, DNA does not perform any such functions when outside a cell. ... Consequently biology, though based on physics and chemistry, is not fully reducible to the latter.(19)

DNA is the "blueprint" of the living organism, but analysis of the blueprint alone does not explain the route from DNA "information" to the actual organism. Ian Stewart and Jack Cohen illustrate the limits of our knowledge:

[T]he common image of an organism's DNA as a "blueprint" begs the question of how the information in the blueprint is actually converted into a functioning organism. We know that some sections of DNA code for proteins, and we have an excellent understanding of how particular DNA sequences lead to the construction of particular protein molecules. We have a few inklings that other sequences of DNA have a more global function, switching other sequences on or off and thereby coordinating protein production. But what goes on between all that and a working organism is a total mystery. If we liken an organism to a ten-course banquet, then our current model of how to produce a banquet is that "it's all in Mrs. Beeton," and about 99% of our effort is going into listing all her recipes, page by page. ... We are convinced that important structures that we observe being used in real banquets, such as "eggbeater" or "oven," are specified somewhere or somehow in the recipe book,...but...we don't know where or how. The concept "kitchen" has not yet occurred to anybody. ... We collectively remain obsessed with sequencing the recipes, and any speculations about the need for eggbeaters or kitchens are dismissed with an airy "it's all in the book," as if they don't matter.(20)

Though chemistry is involved in all biological processes, it is not able in itself to explain them. As Niels Bohr observed, "The recognition of the essential importance of fundamentally atomistic features in the functions of living organisms is by no means sufficient for a comprehensive explanation of biological phenomena."(21)

New features and behaviors emerge in biological organisms that are not found in chemistry. Molecules, for instance, do not run, walk, cry or laugh. Such behaviors cannot be explained by the laws that describe the behaviors of molecules. If anything, the opposite is the case. It is the behavior of organisms that explains the motions of molecules. Roger Sperry describes this kind of top down causality:

[I]n the reciprocal interaction of lower and higher levels, the higher laws and forces (once evolved) exert downward causal control over the lower forces. ... In scientific theory this means that the trajectories through space and time of most of the atoms on our planet are not determined primarily by atomic or subatomic laws and forces, as quantum physics would have it, but rather are determined by the laws and forces of classical physics, of chemistry, of biology, of geology, of meteorology, of psychology, even sociology, politics, and the like. The molecules of all higher living things, for example, are not moved around in our biosphere so much by molecular laws and forces as they are by the living, vital powers of the particular species in which they are embedded. Such molecules are flown the through air, galloped across the planes, propelled through the water, and so on, not by molecular forces (nor by quantum mechanics) but by the specific holistic vital properties possessed by the organisms in question.(22)

This top down causality of the whole organism is evident even on the molecular level, as Holmes Rolston III explains:

A biological molecule, though it is always physical material, is readily separable from merely physical material right down to the molecular level. ... If we examine an iron poker microscopically, its functional character is entirely gross and not evident in the microstructures of the iron. But biofunctioning is structurally present down to 10 nanometers and below. Nonbiologial molecules have only to be; biological molecules have to work in order to be. Otherwise they disintegrate. Indeed, the behavior of the particular atoms and electrons involved, right down to the level of quantum indeterminacies, is not understood until it is understood in terms of a biofunctional analysis.(23)

The causality of the whole is readily evident when part of a living thing is separated from the whole. Though the parts of a machine do not change when they are separated from the whole, the parts of an organism "have properties in situ which they do not have in isolation."(24) The behaviors of cells when studied in vitro, for instance, "can be very different from those which they manifest in the interior of an organism. ... The organism has certain properties because its cells are organized in a certain manner." This organic arrangement "modifies their properties, and their behavior with respect to that which they do when isolated."(25)

4. Getting on top of top down causality

We have seen that, in many areas, science has found properties or characteristic activities of the whole which cannot be accounted for by the part. It has also found instances where the part behaves differently when incorporated into the whole than it does in isolation. How are we to account for these findings?

One way to approach them is througgh the principle that "action follows being." Both science and philosophy use this principle, at least implicitly. In science, for instance, we use it when we determine what kind of particle or chemical or organism we are observing by watching how it acts or reacts. Its action discloses the kind of thing, the kind of being, it is.(26) (If it quacks like a duck, perhaps it is a duck.) In philosophy, we find the ontological grounding for the principle: action follows being because a thing's being is the source of its actions.(27) (So if it is a duck, chances are it will quack like one.)

Since a thing's being is the source of its action, we can account for the action of the thing only if we account for its being. In particular, we can account for the action of the whole only if we account for the being of the whole. We cannot claim that a thing's action is due to the "top down" causality of the whole unless we have first reached the top -- unless we have first accounted for the distinctive being of the whole as a whole. If the "whole" is merely a conglomeration of parts, then it will always be the action of the part that accounts for the whole and not vice versa. How are we to account for the distinctive being of the whole, especially "wholes" such as organisms that are evidently composed of a variety of parts?

And if the action of the part, within the whole, is different from its action in isolation, we have reason to suspect that the being of the part within the whole is different from its being in isolation. How are we to account for the distinctive being (and so for the distinctive activity) of the part in these different contexts?

Different ways of accounting for the being of the whole and the distinctive activity of the part are offered by reductionism, vitalism, and emergence. The first offers a "bottom up" approach; the latter two offer "top down" approaches. We will examine each of these approaches and then consider the "inside out" approach of Aristotelian causality.

4.1. Reductionism

Reductionism sees the whole as an incidental arrangement of parts. The part is the fundamental reality which explains the whole. As a "whole pile" of sand is explained by the individual grains that compose it and a "whole toaster" is explained by its plastic and metal parts, so every "whole" is explained as a product of its parts. If we knew the ultimate parts of the universe (whether conceived as water, fire, air, atoms, or mass-energy), we could explain everything else.

As an incidental arrangement of parts, the whole has only incidental or accidental being. And since action follows being, an accidental whole can have only accidental activity. Properly speaking, it is the parts that are acting. Incidentally, they produce a common effect that is attributed to the whole. So each part of the toaster, for instance, acts according to its own nature, and the combined effect (toasting the bread) is attributed to the toaster.

This approach is adequate so long as the whole produces only incidental activity which can be traced back in principle to the activity of the part. But as we have seen, science is now discovering activities of the whole that cannot be traced back to the part. Reductionism cannot explain such activities since it cannot explain the being of the whole. Nor can it explain why the whole should affect the activity of the part if the whole owes its activity to the part and not vice versa. Reductionism cannot admit top down causality because it never sees the "top"-- the being of the whole from which follows its the proper activity.(28)

4.2. Vitalism

Vitalism sees an essential difference between living things and non- living matter. It explains the being and activity of the whole living organism by attributing to it a vital principle or force (élan) not found in inanimate matter. Though some scientists of this century, such as Niels Bohr, have embraced vitalism, it has generally come in for criticism from the scientific community.(29)

Vitalism seems to do both too much and too little in accounting for the activity of the whole. It does too much by introducing a mysterious new force, the elan vital, that is undetectable to science:

Through it all, biochemistry finds nothing but common chemicals and no sort of elementary force that is not likewise present in physics. ... No separately isolable bioforce, no élan vital has ever been detected in the laboratory.(30)

On the other hand, vitalism seems to do too little since it does not explain how some inanimate entities in nature (such as the sodium atom or the water molecule) also seem to act as "wholes" with activities distinct from their parts. And even among living things, it does not explain how the organism is truly a "whole." If anything, it suggests a fundamental dualism within the organism if inanimate matter, as one sort of entity, is somehow guided by a "vital force" as another sort of entity. The living organism is then not one integral whole but a conglomeration of different things.(31) Although vitalism is sometimes characterized as a kind of top down causality, in reality it seems that vitalism never gets to the top -- to the being of the whole from which its proper activity follows.

4.3. Emergence

In an attempt to get away from the problems of vitalism while maintaining the distinctive being and activity of each whole entity, some thinkers have embraced the notion of emergence. This approach rejects reductionism by asserting that the whole is more than just a conglomeration of parts. It also rejects vitalism, finding no need for a vital force to explain the activity of the whole. Rather the whole, with its distinctive activities, simply "emerges" from the arrangement of the parts. Its activity is not reducible to and cannot be predicated from the activity of its parts. Lloyd Morgan explained the difference between emergence and vitalism is his Gifford Lectures on "Emergent Evolution" in 1923:

Since it is pretty sure to be said that to speak of an emergent quality of life savours of vitalism, one should here parenthetically say, with due emphasis that if vitalism connotes anything of the nature of Entelechy or Elan -- any insertion into physico-chemical evolution of an alien influence which must be invoked to explain the phenomena of life -- then, so far from this being implied, it is explicitly rejected under the concept of emergent evolution.(32)

Ian Barbour makes the same point for all wholes, not just biological entities:

New wholes do not of course contain any mysterious entities in addition to their parts, but they do have distinctive principles of organization as system, and therefore exhibit properties and activities not found in their components.(33)

In emergence, the "part" no longer has a privileged status over the whole. The whole can influence the part, and the part can influence the whole. So John Polkinghorne can argue that "Subatomic particles are not only not 'more real' than a bacterial cell; they also have no greater privileged share in determining the nature of reality."(34)

It might seem, at first, that emergence overcomes the shortcomings of both reductionism and vitalism.(35) Where reductionism sees only "bottom up" causation from more elementary parts and vitalism sees only "top down" causation from some vital force, emergence recognizes both the upward and the downward direction. The more complex structure arises from the "bottom up." It springs from and consists in nothing other than the interactions and relationships at more basic levels. Yet the complex structure can in turn act from the "top down," affecting behavior at more basic levels.(36)

Science explains this top down and bottom up activity through the theories of "chaos" and "complexity." Chaos theory described how complex behavior can arise from simple rules. The classic example is the so-called "butterfly effect," where a butterfly flexing its wings in Beijing sets up a chain of events that eventually leads to new storm patterns over New York.(37) Complexity theory works in the opposite direction, explaining how highly complex interactions can lead to large-scale but simple patterns.(38) So the enormously complex processes within the growing embryo give rise to the mature organism, and the complex interaction of billions of neurons in the brain are said to give rise to consciousness.(39) In each case, there are computer models to show how a simple rule can give rises to complexity and how complex initial conditions can yield simple patterns.(40)

Can emergence explain the top down causality of atoms, molecules and organisms?(41) Using the principle that action follows being, we can say that one will find no secure metaphysical basis for speaking of the causality of the whole unless one first establishes the being of the whole as something more than an incidental arrangement of parts. To the extent that emergence denies to the whole any unity beyond the incidental arrangement of its parts, it fails to explain the being of the whole. And without some grounding in the being of the whole, emergence can only affirm but not explain the activity that proceeds from the whole. So long as emergence remains unable to account for the being of the whole, its tendency will be to slip back into a kind of reductionism, attributing to the part a more fundamental reality than to the whole.

5. Causality from the inside out

Using the Aristotelian notion of substantial form, we can better explain the being and activity of the whole and why the part may act differently within the whole than it does in isolation. First, however, we need to know something about formal causality, and to do that we should know something about the nature of change.

Aristotle recognizes two fundamentally different kinds of change in the natural world.(42) In one kind, called "accidental change," a substance is modified incidentally while remaining the same kind of thing (as a block of clay might be formed into a sphere while still remaining clay). In the other, called "substantial change," the substance itself becomes a different kind of thing (as when a dog dies and so is a dog no longer). In either type, there must be a principle of continuity (something that endures through the change) and a principle of newness. If there is nothing new, there is no change; and if there is no continuity, there may be substitution of one thing for another, but not change of one thing into the other.

5.1. Accidental form

In accidental change, the principle of continuity is a substance (such as the clay). This substance has the possibility or potentiality for some new quality or condition (as the square clay has the possibility to become round). The new quality or condition (in this case the round shape), is called the accidental form. In some way the accidental form actualizes the possibility or potentiality that was there originally in the substance. It does not do this by exerting any kind of force on the substance. Rather, after the mode of a formal cause, it exercises its causality by making the thing to be the kind of thing it is.(43) The round shape, the accidental form, makes the clay actually round. The sculptor, as an efficient cause, may push, pull, tug and bend the clay, but it will not actually be round until it has acquired a round shape. We might say the sculptor causes the clay to become round, but the formal cause (the shape) that causes the clay to be round.

Since action follows being, an accidental form, by causing a thing to be of a certain kind, may also cause it to act in a certain way. By causing the clay to be a sphere, for instance, the accidental form also causes it to act like a sphere. Placed on an inclined plane, for instance, a block of clay does not move, while a sphere rolls down.(44)

Fundamentally, however, the clay remains clay and continues to act as clay throughout this accidental change. Action follows being, and since the clay remains the same kind of being, it exhibits the same kind of action. (Whether it is round or square, rolling or stationary, for instance, the clay exhibits the same gravitational attraction.)

If all changes in nature were accidental -- if in each case the substance remained the same while being modified incidentally -- then reductionism and emergence might account for them. For then the fundamental components of things would remain always the same (as the clay remains the same kind of thing when its shape changes). Remaining the same kinds of things, they would continue to exhibit the same kinds of action. New properties might "emerge" which could affect the basic components in a top down fashion (as the property of rolling emerges from and influences the behavior of the clay), but these would not imply any change in the being of the fundamental components (as the property of rolling does not imply that the clay has become anything other than clay).(45) We have seen instances on the physical, chemical and biological levels, however, where whole entities exhibit activities not explained by their parts. Such new modes of activity suggest that these wholes may be new kinds of being. We have also seen that in some instances the fundamental components of a thing behave differently as part of the whole than they do in isolation. This suggests that, as parts of the whole, they may be radically different sorts of being than they are in isolation. They do not undergo mere incidental rearrangement or restructuring (like the clay). They become different substances. To account for this kind of change, we must consider principles more fundamental than those of accidental change.

5.2. Substantial form

In substantial change, as in accidental change, there must be a principle of continuity and a principle of newness. In this case, however, the principle of continuity cannot be a substance (like the clay) since it is the substance itself that is undergoing the change. The substance is precisely what does not endure through the change. Nor can the principle of newness be merely an incidental factor (such as the shape of the clay) since it is not incidental novelty that needs to be explained, but substantial newness -- a new substance, a new being, as evidenced by radically new activity. Here the principle of continuity is not a substance, but the mere "possibility" of being a substance. It is called "primary matter." And the principle of newness is not a substance. It is not a "thing" or a "what." It is rather "that by which" a thing is the sort of thing or the sort of substance that it is. It is called "substantial form."

5.2.1. Matter as potency

We began this paper by alluding to the perennial search for the ultimate actual stuff of the universe -- the most basic actual component of everything else. We have found, however, that any basic component we name (whether quarks, electrons, atoms, molecules or living cells) is always able to change and become something else. Quarks (the possibility of whose individual existence is still questioned) can become protons or other particles. The electron may become part of the sodium atom. The atom of chlorine may become salt. The cell which exists as part of the dog will cease to be dog and become something else if separated from that organism. If all of these things are substances that can become other substances, there must be some principle more basic than any of them which endures through such changes. Far from being the most fundamental actuality in the universe, this principle, in itself, will have no actuality at all. Not the ultimate actuality, it is something still more basic: the ultimate principle of possibility, that aspect of each things which explains why it can cease to be what it is and become a different kind of thing.(46) It is not a being, but the mere "possibility-of-being." As Norbert Luyten describes it, it is "the constitutive or fundamental inadequacy of substantial determination... It is a constitutive deficiency, that is, it indicates the possibility of this thing's becoming another thing in which latter thing it will again have the meaning of fundamental deficiency."(47) William Wallace describes it as "a radical indeterminacy at the root of all natural changes."(48) Aristotle gives it the name "primary matter."(49)

5.2.2. Form as act

Corresponding to this principle of potency is a principle of actuality, substantial form, which makes a thing to be what it is. Analogous to the way accidental form made the clay to be actually a sphere, substantial form makes primary matter to be actually clay (or a quark, an electron, sodium, a dog, etc.). As the accidental form acted along the lines of formal causality to make the clay to be a sphere, so substantial form acts as a formal cause, to make a thing to be the kind of substance that it is and so to act the way it does. The accidental form was a secondary or incidental actualization. (The substance which was already actually clay became incidentally spherical.) Substantial form is the primary actualization of a substance, the first actualization of primary matter. Substantial form is not something added to a complete substance, as a vitalist "life force" might be added to a conglomeration of inanimate substances. Nor is it a complete substance in itself. It is an incomplete substantial principle, corresponding to the complementary principle of primary matter. Only together do they comprise the one unified actual substance, whether it be the one electron, the one sodium atom, the one chemical compound, or the one living organism. As the round shape caused the clay to be actually round, so the substantial form, for example of hydrogen, causes primary matter be actually hydrogen with the characteristic structure and activity of hydrogen. All "parts" of the substance have the same one substantial form and so are that substance. So the electron in sodium is sodium, not just an electron. And similarly the chlorine in salt is salt and the living cell in the dog is dog. The substantial form is also the source of the characteristic activity of the substance. Making the substance to be what it is, it also causes the substance to act as it does.(50) Since action flows from being, we can think of the form exercising its causality not so much from "bottom up" or "top down," but from "inside out." The substantial form accounts for the being and characteristic activity of the whole.(51) Unlike the vitalist principle, it implies no dualism since it is not itself a complete substance and is not added to an already complete substance. It is an incomplete substantial principle which, together with its complementary principle of primary matter, constitutes the complete substance as one whole. This account may imply duality, but not dualism. And the duality implied is no more than the duality that is evident in nature where each thing, while being the sort of thing it is, is always capable of ceasing to be that thing and becoming something else.

5.3. Substantial form and contemporary science

Our analysis of substantial form can now be applied to some of the instances of the causality of the whole which contemporary science has discovered. Through the "inside out" causality of the substantial form, we can ground the being of the whole and so account for the activity that follows from that being. We can also see why a part may act differently within the whole than it does in isolation If the protons, neutrons and electrons in the sodium atom, for instance, act differently in the atom from the way they do in isolation, it is because within that atom each exists not simply as an elementary particle, but as sodium. As William Wallace explains, each is an integral part of the whole substance: Just as the behavior of the electron in the Bohr atom of sodium is dictated not by the form of electron as this might exist outside the atom but by the unifying form of sodium, so the behavior of the neutron within, say, the liquid-drop model of the nucleus is dictated not by the form of neutron as it might exist outside the atom but by the form of sodium also. In other words, the nature of sodium is such that the specifying form of that element actually informs protomatter in a distinctive way so as to structure all of its components -- the nucleus and its constituents, plus the orbiting electrons -- into an integral whole that responds in a way characteristic of sodium to various external influences.(52) Similarly, the seventeen protons, eighteen or twenty neutrons and seventeen electrons of the chlorine atom do not act as 52 or 54 unrelated entities, but as a single unity in virtue of the substantial form: [T]he distinguishing feature of chlorine is not its material composition but rather the way its components are arranged. But again what is at issue here is not merely a structural or artificial arrangement; rather what is present is a dynamic unity that makes each component of the atom behave not as an independent nature but as a part of chlorine. The unifying or stabilizing form gives specific identity to the element and so constitutes it a natural substance in its own right.(53) The substantial form is not a short cut around the arduous scientific work of discovering the characteristic activities of substances. But it does make those activities intelligible by providing an ontological ground for the being of the whole and so allowing us to speak coherently of the characteristic activities that follow that being: It is because of this unity [of form that gives unity to the substance] that one can speak of an element such as radium as radioactive. The source of radium's radioactivity is indeed lodged in its nucleus, just as the source of its chemical activity is lodged in its valence electrons, but both activities are those of the specifying form of radium, which actually structures the protomatter of which this element is composed and enables it to act and react precisely as it does.(54) As the substantial form causes the primary matter of an atom to exist as chlorine or sodium, each with its characteristic structure and activity, it also causes the primary matter of a living organism to exist as one unified whole with all its complex parts and structures: Each organism effectively constitutes a unity, but a unity which does not deny the difference [of parts] and which is even assured by the existence of the difference... If we do not fear using old notions, we can say that the unity is guaranteed by the form, in the profound Aristotelian sense of this concept, which means at the same time an ontological criterion of specificity, a factor of organization, and of functional and finalized coordination.(55)

6. Conclusion

Some three centuries ago, the notion of substantial form was largely abandoned by the scientific community since, like final causality, it was neither quantifiable nor empirically observable, and so lay "beyond the reach of experiment."(56) Ironically, it is now the very discoveries of contemporary science that invite its reconsideration. We have seen that science is becoming increasingly aware of a causality of the whole at the atomic, molecular and biological levels -- a causality that cannot be accounted for by an analysis of the part. Since action follows being, an explanation of the causality of the whole requires an account of the being of the whole. We have noted that reductionism, vitalism and emergence all fail to explain this adequately. By retrieving the Aristotelian notion of formal causality, we have been able to make sense of the being of the whole and its consequent activity. In this way, we can also make sense of the kinds of causality that science is now discovering, seeing them not from bottom up or top down, but from inside out.



1. See E.A. Burtt, Metaphysical Foundations of Modern Science Garden City, N.Y.: Doubleday, 1954, p.81.

2. Ian Barbour defines reductionism as "the attributing of reality exclusively to the smallest constituents of the world, and the tendency to interpret higher levels of organization in terms of lower levels." --Ian Barbour, Issues in Science and Religion, (Englewood Cliffs, N.J.: Prentice Hall, 1966), p.52. On the origin of the term "reductionism" see Manfred Stöckler, "A Short History of Emergence and Reductionism," in E. Agazzi, The Problem of Reductionism in Science, Dordrecht: Kluwer Academic Publishers, 1991, p.71-90.

3. F.J. Ayala, "Biology as an autonomous science," American Scientist 56(1968) 207, quoted in Renzo Morchio, "Reductionism in Biology, in E. Agazzi, The Problem of Reductionism in Science, Dordrecht: Kluwer Academic Publishers, 1991, p. 149-160, at 151. Quoting E. Nagel, Ayala says that two formal conditions must be satisfied to effect the reduction of one science to another one: "the condition of derivability (all the experimental laws and theories of the 'reduced' science must be shown to be logical consequences of the theoretical constructs of the primary science) and the condition of connectability (if the laws of the 'reduced' science contain some terms that do not occur in the primary science it is necessary to establish suitable connections between the terms of the two sciences through a redefinition of the terms of the secondary science, using terms of the primary science)." (Renzo Morchio, p.151).

4. E. Agazzi, "Reductionism as Negation of the Scientific Spirit," in E. Agazzi, The Problem of Reductionism in Science, Dordrecht: Kluwer Academic Publishers, 1991, p.14.

5. E. Agazzi, "Reductionism," p.14. Hans Primas uses stronger language regarding certain claims that one science has been reduced to another "In their famous paper on reductionism, Kemeny and Oppenheim write: '...a great part of classical chemistry has been reduced to atomic physics.' No reference for a proof are given. Evidently, the authors have no idea what they are talking about. Queries: How are the non-linear differential equations of chemical kinetics derived from linear quantum mechanics? Does there exist a universal relation between chemical substances and molecules?" -"Reductionism: Palaver without Precedent," in E. Agazzi, The Problem of Reductionism in Science, Dordrecht: Kluwer Academic Publishers, 1991, p.161-172, at 163.

6. See E. Agazzi, "Reductionism," p.24.

7. Democritus as quoted by Galen in Milton Nahm, Selections from Early Greek Philosophy, New York: Appleton-Century-Crofts, 1964, p.160.

8. Galileo Galilei, Opere Complete di Galileo Galilei, (Firenze, 1842), vol. IV, p.336, as quoted in E.A. Burtt, Metaphysical Foundations of Modern Science Garden City, N.Y.: Doubleday, 1954, p.86, 88.

9. Ian Stewart and Jack Cohen, "Why are there Simple Rules in a Complicated Universe," Futures 26(1994) 648-664 at 650.

10. "However, if we do discover a complete theory, it should in time be understandable in broad principle by everyone, not just a few scientists. Then we shall all, philosophers, scientists, and just ordinary people, be able to take part in the discussion of the question of why it is that we and the universe exist. If we find the answer to that, it would be the ultimate triumph of human reason -- for then we would know the mind of God." --Stephen Hawking, A Brief History of Time, New York: Bantam, 1988), p.175.

11. Ian Barbour, Religion in an Age of Science, (San Francisco: Harper, 1990), p.104.

12. Ian Barbour, Issues, p.295; cf I. Barbour, Religion, p.105.

13. William Wallace, The Modeling of Nature: Philosophy of Science and Philosophy of Nature in Synthesis, (Washington, D.C.: Catholic University of America Press, 1996) p.46-47.

14. Ian Barbour, Religion, p.104-105. cf: Issues, p.295-6

15. Henry Margenau, The Nature of Physical Reality, p. 442, 444, quoted in Ian Barbour, Issues, p.296.

16. Ian Barbour, Religion, p.104-105.

17. E. Agazzi, "Reductionism", p.20.

18. Francis Crick, Of Molecules and Men (Seattle: U. of Washington Press, 1966, p.10, 14, quoted in Holmes Rolston III, Science and Religion: a Critical Survey, (New York: Random House, 1987), p.84.

19. Mario Bunge, "The Power and Limits of Reduction," in E. Agazzi, The Problem of Reductionism in Science, Dordrecht: Kluwer Academic Publishers, 1991, p.43-44.

20. Ian Stewart, "Simple Rules," p.656.

21. Niels Bohr, as quoted in Roger Lewin, Complexity: Life on the Edge of Chaos (New York: Macmillan, 1992), p.179.

22. Roger Sperry, "Changed Concepts of Brain and Consciousness: Some Value Implications," Zygon 20(1985) 48.

23. Holmes Rolston III, Science and Religion, p.84. Richard Green also affirms that living things must act in order to be, since they must continuously overcome the effects of the second law of thermodynamics: "the living thing needs energy to overcome such disruptive effects of the second law of thermodynamics as the natural tendency for the distinctive concentrations and distributions of molecules comprising a living thing compared with its surroundings to become dissipated. (The same tendency is a work when a hot potato cools, eventually becoming the same temperature as it s surrounding.) On this analysis the defining attribute of lie is its metabolism, understood as a sort of fight against the effects of the second law." "The boundary separating living things from things that are not alive is sharp. Only living things use energy to counter the threats to their structural integrity arising from the effects of the second law of thermodynamics and other hazards." --Richard Green, The Thwarting of Laplace's Demon: Arguments against the Mechanistic World-View, (New York: St. Martin's Press, 1995) pp.8, 170.

24. Ian Barbour, Issues, p.327.

25. E. Agazzi, "Reductionism," p.20-21.

26. Galileo noted, "it is apparent that a different motion indicates a different nature." Quoted in Wallace, Modeling, p.3.

27. "For since everything acts insofar as it is actual...and since every being is actual through form, it is necessary for the operation of a thing to follow its form. Therefore, if there are different forms, they must have different operations." --SCG 3, 97, nr.4. "Everything, according as it is in act and is perfect, is the active principle of something." --ST I, 25, 1, co. cf: ST I-II, 6, 1, co.; SCG 2, 6, nr.4; Sent. IV, 49, 2, 3, ad 6. "Praeterea agere sequitur ad esse perfectum, cum unumquodque agat secundum quod est in actu." --Sent. III, 3, 2, 1, co. "...agere sequitur ad esse in actu..." --SCG 3, 69, nr.20. "Essentia...est principium actus in supposito." --Sent. I, 5, 1, 1, co.

28. While we can suggest inadequacies in the reductionist approach, we cannot completely overcome the reductionist mentality since the reductionist can always appeal to still more fundamental and as yet undiscovered parts and properties: "If one begins with the presupposition that life does not correspond to something superior with respect to inanimate matter, if one begins from the presupposition that the intelligence is not something superior with respect to matter, one intends to prove that, and estimates that one should be able to do it: reduction then appears as a way to successfully implement this program and no failure is able to make one desist from this purpose, for he will say that, in principle, reduction is possible, but that we still need time and research in order to complete it." --E. Agazzi, "Reductionism," p.26. It is not difficult to find examples of this mentality: 'Consciousness is not something that can be said to be present in a single atom or even in a single neuron, for that matter. Just as one has different properties in a water molecule than were present in the two hydrogen and one oxygen atom that comprise the molecule, so the organized mass of neurons and glia in the brain can have different properties. It is the organization of the matter that gives rise to the ability to develop subjective experience and personal self. Today many physicists feel relatively confident that the properties of a group of water molecules, such as boiling pint and density, can be predicted or approximated from a knowledge of hydrogen and oxygen atoms by using quantum mechanics. This is a reductionistic view of the water molecule. The reductionistic view receives support from the demonstration that quantum mechanics can predict the properties of the hydrogen molecule (H2) from a knowledge of hydrogen atoms (H) alone. For water and other molecules, the difficulties appear to arise more from complexity of calculations that from inadequacy of principles. We may someday be capable of a description of mental processes from a knowledge of neurons, glia, and brain structure. Such properties as consciousness may be new but that does not make them emergent in the philosophical sense of the term. [See P.E. Meehl and W. Sellars, "The concept of Emergence." in H. Feigl and M. Scrivden eds, Minnesota Studies in the Philosophy of Science. Minneapolis: U. of Minn Press, 1956. An emergence hypothesis would consider mind and consciousness to be subject to scientific analysis but would consider the analysis to involve new laws and principle going beyond the laws that govern inanimate nature. Emergence does not necessarily entail violation of the laws of physics and chemistry, but does assert that such laws will be incomplete and incapable of accounting for higher brain functions. Without compelling evidence, the postulation of emergence unjustifiably precludes reductionistic approaches to understanding mind.' --David L. Wilson, "Brain Mechanisms, Consciousness, and Introspection," in Expanding Dimensions of Consciousness, A. Sugerman and R. Tarter, eds., (New York: Springer, 1978), p.10.

29. See Roger Lewin, Complexity, p.179.

30. Holmes Rolston III, Science and Religion, p.83-84.

31. Ian Barbour remarks that the vitalist "turns out to be a mechanist at heart, since he merely adds an invisible agent to run the machine!" -Issues, p.326.

32. C. Lloyd Morgan, Emergent Evolution (Gifford Lectures, 1922), London: Williams and Norgate, 1923, p.12. For an overview of emergence and top down causality, see Bernd-Olaf Kuppers, "Understanding Complexity," in Chaos and Complexity: Scientific Perspectives on Divine Action, (Vatican City: Vatican Observatory Publications, 1995), p.95-105.

33. Ian Barbour, Issues, p.297. cf: Religion, p.105. E. Purcell argues that there are "new organizing principle as we proceed from the individual to the system," which result in "qualitatively new phenomena." E. Purcell, "Parts and Wholes in Physics," in D. Lerner, ed., Parts and Wholes (New York: Free Press of Glencoe, Inc., 1963), quoted in Ian Barbour, Issues, p.296. Holmes Rolston III names "information" as the principle that separates life from non-life: "What is irreducibly there is not entelechy but vital information. This is the 'force' that animates matter so distinctively. ... Here is what more there is in life, a 'more' never found in physical matter: an informed organization of ordinary chemicals, a morphology and metabolism extraordinary for physics and chemistry, though ordinary to life. Life thus involves no new physical force, no new materials, but it does involve a new process and power, that of informational control." --Holmes Rolston III, Science and Religion, p.85, 86.

34. John Polkinghorne, Reason and Reality, (Philadelphia: Trinity Press International, 1991), p.39.

35. Sohail Inayatulla, for instance, argues: "Complexity theory claims to resolve the classic conflict between vitalists who believe evolution is externally caused by spirit or other vital forces and mechanists who believe evolution is bottom-up, with survival of the fittest or adaptation as the key variable. In contrast, complexity theory asserts that evolution occurs through emergence. ... From simple conditions emerge complex conditions." -"Life, the Universe and Emergence," Futures, 26(1994)683-696 at 683.

36. Roger Lewin provides a diagram to illustrate this in Complexity. p.189.

37. See Roger Lewin, Complexity, p. 11; John Polkinghorne, Reason and Reality, p.36.

38. See Ian Stewart and Jack Cohen, "Simple Rules," p.648-649.

39. Roger Lewin, Complexity, p.13-14.

40. In a computer model one can follow the movements of "Langton's ant." (See Ian Stewart and Jack Cohen, "Simple Rules," p.659-660.) In the real world, one can watch the patterns of movement of a fluid between two horizontal plates as the lower plate is heated in the phenomenon of Bérnard instability. (See John Polkinghorne, Science and Creation (Boston: Shambhala, 1988), p.45.)

41. See, e.g., I Stewart and J. Cohen's argument that the top down and bottom-up views in fact never meet, but disappear into a vague middle ground that they call "ant country" (after Langton's ant), a territory we traverse by "substituting computer simulations for proofs, making far reaching generalizations from a few special solutions." -"Simple Rules," p.657, 661.

42. Aristotle, De Generatione et Corruptione, I, 4 (320a 1-2) in W.D. Ross, ed., The Works of Aristotle (Oxford: Clarendon Press, 1930), Vol. II.

43. Aristotle, Physics Book II, c.7 (198a 15-20). cf: Thomas Aquinas, Commentary on Aristotle's Physics, R. Blackwell et. al., trs., (New Haven: Yale U. Press, 1963), Book II, lecture 10, nr.240, p.110.

44. William Wallace explains this in the case of the round shape of a wooden wheel. Modeling of Nature, p.11.

45. There is a sense, even on the accidental level, in which a whole is more than a collection of parts. Å

46. Noting that the elementary particles of modern physics can all be transmuted into other particles and into energy, Werner Heisenberg suggested that "all the elementary particles are made of the same substance, which we may call energy or universal matter" and compared this substance to Aristotle's primary matter: "If we compare this situation with the Aristotelian concepts of matter and form, we can say that the matter of Aristotle, which is mere 'potentia,' should be compared to our concept of energy, which gets into 'actuality' by means of the form, when the elementary particle is created." We would note only that Heisenberg has not yet achieved a level as basic as Aristotle since energy itself already has some actuality and so is not the same principle as Aristotle's primary matter which, having no actuality at all, is more basic than energy. See Werner Heisenberg, Physics and Philosophy, (New York: Harper and Row, 1958), p.160.

47. Norbert Luyten, OP, "Matter as Potency," in E. McMullin, ed., The Concept of Matter, (Notre Dame: U. of Notre Dame, 1963), p.108.

48. Wallace, Modeling of Nature, p.56.

49. "Aristotle spoke of the ultimate material component of natural entities as hule prote, a Greek expression meaning protomatter (PM) or first matter. In the second book of the Physics, 193a28-29, [Aristotle] describes it as the 'immediate material substratum of things which have in themselves a principle of motion or change.' Earlier he had identified it in the first book as the hypokeimene phusis or the 'substratum of nature' or simply as hule or 'matter' (191a7-11)." --W. Wallace, Modeling of Nature, p.8

50. "Natural forms are the inner source of these activities, but such forms are equipped with powers that can be activated and so enable substances to act on, and interact with, things external to them in distinctive ways. It is the ability of one substance to act on another that explains why it is possible to identify agents and reagents in the order of nature." --W. Wallace, Modeling of Nature, p.12. To get a complete picture of the thing's actions and reactions, we must refer both to substantial form and primary matter. Together they constitute the "nature" of the thing, the ontological ground of the thing's characteristic actions and reactions. Aristotle defines "nature" in his Physics (192b21-3) as: 'a principle and cause of being moved or of rest in the thing to which it belongs primarily and in virtue of that thing, but not accidentally.' "Another sense of the natural differentiates it not from the artificial but from the forced or violent, what is done from without or by coercion instead of coming from within the subject being studied. In this way of speaking, things have natures that are the sources of the activities they originate and so are peculiarly their own." --See W. Wallace, Modeling of Nature, p.3.

51. On the respective roles of accidental and substantial forms regarding accidental and substantial wholes, see Laura Landen, "Of Forests and Trees: the Limits of Form," American Catholic Philosophical Quarterly 69(1995) 81-89, at 84-86.

52. Wallace, Modeling of Nature, p.56-57. cf: "One who comprehends the Bohr model must see that none of the three components of the sodium atom [12 neutrons, eleven protons and eleven orbital electrons] acts simply as an electron, proton, or neutron, that each functions instead as a part of sodium. The form that is known and that is modeled in the Bohr atom is therefore a natural form, a unifying form that confers substantial identity on the parts that make up the composite.... It gives unity to the parts by specifying the substance they compose as sodium, and it stabilizes them by rearranging them, when necessary, to maintain that element's specific identity." Wallace, Modeling of Nature, p.46.

53. Wallace, Modeling of Nature, p.48.

54. Wallace, Modeling of Nature, p.57

55. E. Agazzi, "Reductionism," p.23.

56. Mario Bunge, Causality and Modern Science, (New York: Dover, 1979), p.32. William Wallace notes, however, that such causes were not immediately abandoned by modern science. The material cause was sought by Galileo, Newton and Hobbes, and the formal cause, by Gilbert, Kepler and Bacon. The final cause "was not generally accorded explanatory power within the physical sciences" in the classical period, but was still used by Leibniz in physics and Harvey and Bernard in biology. Wallace notes that "only in the contemporary period has causality generally been narrowed to its Humean understanding." The See Causality and Scientific Explanation, (Ann Arbor: U. of Michigan Press, 1974), vol.2, p.246.