Philosophy of Nature

What it asks

Natural philosophy was the old name for what is now science, and when the sciences separated they took the empirical questions with them. What was left is a set of questions the sciences use and do not examine.

What is a law of nature - a rule the world obeys, or a summary of what it happens to do? Are there natural kinds, joints at which the world genuinely divides, or does every classification reflect an interest of the classifier? And is anything natural, once a species has reshaped the surface of the planet it evolved on?

The recurring problems

What makes a law a law. Every gold sphere is under a mile across, and so is every uranium sphere, but only one of those is a law - the other is an accident. The Humean answer, that laws are the best summary of what happens, has to explain that difference without appealing to necessity. The alternative posits necessity and has to say what it is.

Natural kinds. Chemical elements look like real divisions; species are messier; races are not kinds at all. Where the line falls between finding a category and imposing one is not settled.

The natural and the artificial. A beaver dam is natural and a hydroelectric dam is not, though both are structures built by animals to hold back water. Any principled version of the distinction has trouble with that case.

Whether nature is one subject. The natural world is studied by a dozen sciences that do not reduce to one another, and the assumption that they are describing a single layered thing is a philosophical position rather than a finding.

How it developed

Aristotle's Physics is the founding work, and its question is what it is for something to have a nature - an internal principle of change - as against being made.

The seventeenth century replaced natures with laws. On the new picture, matter is inert and behaves as it does because of rules imposed from outside, which suited a theological framework and outlasted it.

The German Romantics reacted with Naturphilosophie, treating nature as a single developing organism rather than a mechanism. It was speculative, was largely discredited, and is more influential than that suggests, since much environmental thought descends from it.

The twentieth century split the subject. The empirical part became physics, chemistry and biology, and philosophy of nature survived as the study of laws, kinds, dispositions and powers - with a recent revival of exactly the Aristotelian idea the seventeenth century discarded, that things have causal powers in virtue of what they are.

The positions within it

Humean regularity and necessitarian accounts divide over laws. Dispositionalism revives natures as causal powers. Mechanism and organicism divide over whether nature is a machine or a system with its own tendencies. All are in the Schools section.

Where it stands now

Powers and dispositions are the growth area, and their return has made this the branch where a genuinely pre-modern position is again live.

The distinction between natural and artificial has meanwhile stopped being an academic question. Gene editing, synthetic organisms and climate engineering all turn on it, and environmental ethics keeps discovering that its central term will not hold still.