November 28, 2013, by Neil Sinclair

Biodiversity Offsetting and Extrinsic Properties

In September the UK government published a consultation paper on “biodiversity offsetting”. This is a mechanism whereby damage to one part of the natural environment (in the process of development) is compensated for by nurturing or creating a different part of the natural environment. Nottinghamshire is involved in the piloting phase.

The scheme raises the issue of whether there is a type of value in nature whose loss cannot be compensated and this in turn raises the issue of what makes nature valuable in the first place.

Some philosophical distinctions help map out the possibilities. One distinction is between intrinsic and extrinsic properties. Roughly, an intrinsic property of an object is one that can be understood entirely in isolation of that object’s relations to other things. An extrinsic property is one that cannot be so understood. So, for example, mass is an intrinsic property, but being created by humans is extrinsic.

Now suppose that the value of nature is wholly dependent on its intrinsic properties. Intrinsic properties can usually be recreated. For example, suppose that the value of a forest depends on the number of sentient individuals it contains. It is (logically) possible to destroy this forest and recreate another one with the same number of sentient individuals. But suppose the value of some things, and in particular the value of nature, depends at least in part on extrinsic properties. Suppose, for example, the value of a forest partly depends on extrinsic facts about its causal history or facts about its particular location, i.e. relation to other things. (This view is expressed by George Monbiot, here, at 2.46pm, and defended by Robert Elliot). On this view, for example, the fact that a forest is untouched by human hands, and has developed organically, unaided by human design, adds to its value. And, of course, these properties are much harder to recreate. If we replant a forest in compensation for one that we have destroyed, then by definition it will be a human creation. If the value of the original forest in part depends on its untouchedness then this value is irretrievably lost.

So whether or not the value of nature can be adequately compensated for turns on the issue of whether that value depends on the extrinsic properties of nature (more precisely on aspects of its causal history).  It seems we need to settle the latter issue before we can know whether the proposed biodiversity offsetting scheme really does provide adequate compensation for lost natural value.

One last thought: In some cases it is clear that the value of an object does depend on its causal history: this is why art forgeries are less valuable than originals. If the value of nature is analogous, then we have grounds for thinking that it can depend on extrinsic properties like causal history.


Lewis, David (1983a), “Extrinsic Properties”, Philosophical Studies, 44: 197–200.

Robert Elliot (1982). “Faking Nature”, Inquiry 25 (1):81 – 93.

Posted in Ethics