Many critics of science, including Christian philosophers like Alvin Plantinga and William Lane Craig,attack something they call “naturalism”, the view that the natural world is all there is. As Papineau notes in the Stanford Encyclopedia of Philosophy entry, the term has no very precise meaning in philosophy, or in science. However, as he goes on to note, there are two streams: ontological naturalism (the view that all that is, is natural) and methodological naturalism (the view that all that can be known can be known via natural methodologies such as scientific method). It is the former that I want to discuss today.
Naturalism relies upon there being some meaning to the term “nature”. It derives from the Latin word natus, meaning, birth. Nature is (in a human context) what you are born with. The Greek cognate term that natura translates is ousia which is a form of the verb “to be”. But despite the role that ousia played in Christian theology (the phrase “not one iota of difference” has to do with the Eastern and Western churches disputing whether the Son was of the same nature as the Father – homoousias – or a similar nature as the Father – homoiousias – quite literally one iota of difference, which split Christendom), it is the Latin term that plays a crucial role in western philosophy.
We often see advertisements that something is “all natural”, which philosophically is an absurd claim: if it exists, it is natural even if synthesised in an industrial chemical vat. And it should also be noted that arsenic is a natural substance, so make of that what you will. The word “natural” carries a lot of connotations.
John Stuart Mill, in an influential 1874 essay, noted that
As the nature of any given thing is the aggregate of its powers and properties, so Nature in the abstract is the aggregate of the powers and properties of all things. Nature means the sum of all phenomena, together with the causes which produce them; including not only all that happens, but all that is capable of happening; the unused capabilities of causes being as much a part of the idea of Nature as those which take effect.
“Nature”, however, is often held to exclude the “supernatural”, which is defined against the natural. If nature is all there is and their properties, then the supernatural doesn’t exist, or is propertyless. This cannot be the view Plantinga and Craig wish to defend, so the question remains: what is nature? Mill goes on to note that the natural is regular and lawful, that it behaves in ways which are predictable. This view is stressed, but not broken, by the existence of stochastic quantum properties like quantum foam and Hawking radiation. The regularities are just now the properties of ensembles of things, rather than of the things themselves.
This leads to the reason why ousias and nature were introduced. Around the 6th century BCE, a group of philosophers known as the Milesians started to ask what things were made of and how their properties led to the phenomena we see around us. Previously, explanations of events were tied into the role the gods played, rather capriciously and whimsically, in bring these events about. Gods were responsible for the seasons, fertility, and catastrophes. Science began when the assumption was made that the causes of things were the properties of the parts of things, which permitted us to begin to investigate these causes.
The supernatural, then, is that which does not follow from the regularities of the properties of things. The gods may have their own natures, but these are hidden from us, and their plans are opaque.
So Mill is roughly right: nature is the inherent properties and capacities of things.But the word “nature” is much more nuanced than this bare philosophical analysis. In our modern world, it has a number of meanings. The historian of nature, Peter Coates, notes five meanings:
1 – nature as a particular set of physical places, notably those parts of the world more or less unmodified by people. This meaning is captured in the phrase ‘unspoiled nature’;
2 – nature as all physical places and things, including those touched and untouched by people. Nature in this sense more or less equates with the word ‘environment’;
3 – nature as force or entity with almost religious qualities. This meaning is captured in the phrase ‘mother nature’or the ‘laws of nature’ which cause certain things to happen;
4 – nature as an essence, for example phrase human nature to explain certain behaviours;
5 – nature as the opposite of culture, so that it is everything that has nothing to do with humans.
[Coates, Peter (1998) Nature: Western attitudes since ancient times, Polity Press, Cambridge, pp 3–10.]
Nature in our time means, broadly, the world apart from human beings. Why are humans usually exempted from nature? The roots of this go back a long way. For the bulk of our existence, we humans lived as foragers (which used to be called “hunter-gatherers” by anthropologists). Like all species, though, we constructed our environment as much as we depended upon it. Elephants, for example, knock down trees and generate grassland savannahs and paths through forests. We used fire farming, selective hunting, and coevolution with other species like dogs to create our environments. Around 12,000 years ago, though, we began to use agriculture (called the neolithic transition in anthropology), and this affected our environments enormously. With a larger population density, and the effects of goats and cattle, we changed a heavily wooded Europe and the Ancient Near East into sparse shrub-dominated regions. The same thing happened also in America and Australia before the Europeans arrived. Megafauna and animals like lions and bears were hunted to local extinction. We constructed a human environment rapidly.
The availability of large food stores permitted an increase in populations. The first cities, like Ur in Mesopotamia (modern Iraq), had thousands of individuals. By the time Rome hit its stride, that was millions. And the constructed environments we created were inward looking. In urbanised civilisations (the very word gives it away: city-fied), human society was more isolated from nature and even the rustic tradition in Rome was not for wild nature, but a tame agricultural environment. We saw ourselves as distinct from nature, taming it, or civilising it. The Christian tradition, in which humans were the pinnacle of creation and had dominance over nature, led further into this dualism of human/natural. As Lynn White said, the roots of our modern ecological crisis are the medieval institutionalisation of the Christian view that we dominate nature. Nature is there for us to exploit. Even so bucolic an author as Gilbert White, whose Natural History of Selbourne in the 18th century is regarded as a paen to nature, thought that the purpose of nature was for humans to find useful items. As historian Donald Worster notes:
These notes of pious admiration for the ecological order apparently did not interfere seriously with another assumption White carried along his rambles. The productions of nature, he was sure, exist partly, if not chiefly, to provide a benign and profitable environment for mankind. [Nature’s Economy: A history of ecological ideas, Cambridge University Press, Cambridge, 1977, p8]
The “Arcadian” vision of nature was something for the benefit of humanity, decreed by a benevolent deity. So our separation from nature was based upon our agrarian, civilised, theistic vision of ourselves.
In recent years, we have seen a trend to “naturalise” humans, however. We have discovered the natural causes of mental activities and failures, of our physiology, our evolution, and even our abilities to know the world. Philosophers have attempted (or objected) to “naturalise” our epistemology, our ethics and our behaviours. A seminal essay by perhaps the most influential of American philosophers of the last century, Quine, was entitled “Epistemology naturalized”, in which he gave an evolutionary account of how it is that we can reliably know our world: evolution has made us thus:
Creatures inveterately wrong in their inductions have a pathetic but praiseworthy tendency to die before reproducing their kind. [Quine, W.V.O., 1969, Ontological Relativity and Other Essays, New York: Columbia University Press, p126.]
And this brings us back to our starting point. Plantinga argues that naturalism, if true, is self defeating. He calls this the Evolutionary Argument Against Naturalism [I have previously discussed this here, here and here]. If we evolved, then we have no warrant for our beliefs, since our beliefs are unreliable. So we cannot use evolution to reject the idea of God. Or something. But humans are a part of nature, as our present ecological crisis indicates. What we do has ecological consequences.We are just as bounded by nature as anything else, and our knowledge of the world depends on our being able to eliminate false beliefs, either through survival of the more correct, or by a process of eliminating beliefs that are unreliable (as in science).
In the end our idea of nature is incoherent or needs to be revised to be coherent, as Mill suggested. The world has its properties, and behaves regularly, and if there is a supernatural realm, then it cannot be investigated unless it, too, follows regular patterns.