The Philosophy of Nature

A Guide to the New Essentialism

Brian Ellis

• Publisher: Routledge
• Year: 2014
• eBook ISBN:
  9781317489498
• Print ISBN:
  9781902683614
• Subtopic: Philosophical Metaphysics

In "The Philosophy of Nature," Brian Ellis provides a clear and forthright general summation of, and introduction to, the new essentialist position. Although the theory that the laws of nature are immanent in things, rather than imposed on them from without, is an ancient one, much recent work has been done to revive interest in essentialism and "The Philosophy of Nature" is a distinctive contribution to this lively current debate. Brian Ellis exposes the philosophical and scientific credentials of the prevailing Humean metaphysic as less than compelling and makes the case for new essentialism as an alternative metaphysical perspective in lucid and unambiguous terms. This book develops this alternative metaphysic and considers the consequences for philosophy, and for some other areas of investigation, of working with such a metaphysic. Ellis argues that these consequences are profound and that a new essentialism provides a comprehensive new philosophy of nature for a modern scientific understanding of the world.

Chapter 1
Essentialist Philosophies of Nature

Classical essentialism

Classical essentialism was a theory of nature developed in ancient Greece, mainly by Aristotle (4th century BCE), to provide a metaphysical foundation for the science of that time. It sought to explain and synthesize Greek knowledge in fields as diverse as cosmology and biology. It was the cornerstone of Aristotle’s metaphysics. Aristotle believed that the world below the sphere of the moon consists ultimately of four elements (earth, air, fire and water), while the heavens above are composed of a special element (the ether) that is essentially different from any of the others. Each natural kind of object, or substance, he thought, has its own special place in the cosmos, and its own natural motion. Thus, heavenly bodies were supposed naturally to move in circles (or combinations of circles) about the centre of the cosmos, while terrestrial bodies of the various kinds all had their proper places, and would naturally return to these places by the shortest paths should they be forced out of them. There were no forces required to maintain the circular motions of the stars or planets, Aristotle argued, and none were required to bring heavy objects back to earth, once they had been lifted up, for these motions were all natural motions. Forces would only be required to prevent them from occurring, or cause the bodies to move otherwise.

Aristotle believed that the things that exist in the world can all be divided into those that exist by nature, those that exist by art and those that exist by chance. Those that exist by nature, Aristotle supposed, include the animals and their parts, the plants and the elements of which all terrestial and celestial bodies are ultimately composed. The things that exist by nature, Aristotle argued, are distinguished from things of other kinds in that each has within itself (Aristotle’s emphasis) various principles of change and resistance to change: principles that are the intrinsic causes of its formal development (its formal causes), and of its role in nature (its final cause). These principles, Aristotle argued, are distinctive of the various kinds of things that exist by nature, and are definitive of them. They are their essences. The essence of an elephant, for example, is the particular set of principles of growth and development inherent in the semen of the male elephant that sired it, and it is in virtue of its having just these principles (and, of course, this particular father), that it is the elephant it is. (Aristotle thought that the mother mainly had the lesser role of supplying the matter for the embryo’s development, but he did allow that she might have some influence on the form.)

In general, Aristotle believed that material objects of various kinds are distinguished from each other by the substances of which they are composed (their material causes), by their shapes, sizes, textures, arrangements of parts and so on (their formal causes), by what brought them into being (their efficient causes), and by the purposes for which they exist (their final causes). The “natural kinds”, as we should now call them, are distinguished by being the products of nature, rather than those of art or chance.

According to Aristotle’s theory, things of different natural kinds must be essentially different from each other: they must have different intrinsic determinants of their characteristics and development. Aristotle did not, of course, deny that the actual development of a thing that is a member of a natural kind may be affected by poor nutrition, or by other accidental circumstances. But these are extrinsic (efficient) causes, he would have said, acting to counter or modify the natural development that is intrinsically determined. Thus, an animal that is naturally four-legged might lose a leg through accident, but it still remains essentially a four-legged creature, for that is what it is by nature. Aristotle was thus able to solve the ancient (even in his day) problem of identity through change. The acorn and the oak tree are two very different objects. Nevertheless, they may be just different stages of what is essentially one and the same thing.

If things that are members of a given natural kind must be essentially the same – have the same internal dynamic – then we should expect to find that these things have certain distinctive characteristics that are the direct consequences of their essential sameness. The distinctive characteristics will necessarily include those that anything must have if it is to be a member of the kind, or which nothing could lose without ceasing to be a member of it. Aristotle’s essentialism thus leads to a very important distinction between essence and accident. The essence of a thing refers to those characteristics it has by nature, and that it could not lose without becoming denatured – that is, ceasing to be a thing of that nature. The accidental properties of a thing are those it has acquired accidentally, or that depend on its particular circumstances, and that it could lose without loss of identity.

Aristotle’s essentialism was developed primarily to explain the existence and continuation through many generations of apparently distinct species of animals and plants, the degree to which these species are evidently adapted to the world about them, the separations of function of the various parts of animals, and the specific design features of these parts. Aristotle believed that these salient facts about the animal and plant kingdoms could be explained if it could reasonably be supposed that each animal and plant has within itself a certain intrinsic capacity for development, which could be passed on in the process of reproduction to the next generation. The concepts of formal and final causation that are postulated to account for this capacity are thus central to Aristotle’s account of these matters, and it comes as no surprise to learn that the essence of an animal or plant kind consists of the formal and final causal powers of its soul (human, animal or vegetative). Aristotle can thus be said to have believed in the existence of intrinsic causal powers.

The final cause is said by Aristotle to be “that for the sake of which a thing is (i.e. exists)” (Metaphysics V, 1013a, 33). Final causes are thus essentially purposive, and explanations given in such terms are said to be “teleological” (from the Greek word telos meaning, roughly, “purpose”). Philosophers and scientists today would generally agree that teleological explanations have no role to play in science. They are relevant to understanding works of art or craft, perhaps, where the artist’s or the craftman’s intentions are in question. But they are not relevant in such fields as physics or biology, where the objects of study are not artefacts, but things that exist by nature. It is true that we are often interested in the causal roles of things in complex ongoing systems (as we are, for example, in ecology or physiology). That is, the question of how something functions to help maintain the system is raised. But this is not a question of purpose; it is one of functional role, which is different. If something is brought into being in order to fulfil a certain role, then it is brought into being for this purpose. But something might happen to exist that fulfils a certain role, even though it was not brought into being for this purpose. It might just have this role accidentally. Aristotle’s telos is therefore much more like purpose than it is like functional role, for the telos of anything that exists by nature is never accidental. Indeed, Aristotle assumes that everything that exists by nature has a telos that belongs to its essence. Hence the telos of anything that exists by nature exists independently of anything else. He further postulates that the ultimate aim of all philosophical (including scientific) enquiry is to know the telos of things: the reasons for their existence. In this sense, the final cause is the highest of all causes.

Modern essentialism

The new essentialism retains the Aristotelian idea that there are natural kinds of substances (roughly, kinds of things of a material nature), but rejects Aristotelian essentialism about animal and plant species. According to the new essentialism, the true natural kinds of substances exist only at a much deeper level than that of living species. They include the basic kinds of physical and chemical substances, such as the various species of atoms, molecules and subatomic particles, but not the biological kinds. The biological species concepts are really cluster concepts, a modern essentialist will say. They have some similarities with natural kinds concepts, as we shall see, but the biological species are not natural kinds.

The new essentialism also retains Aristotelian ideas about essential properties, but it distinguishes more clearly than Aristotle ever did between “individual essences” and “kind essences”. The individual essence of a thing is the set of its characteristics in virtue of which it is the individual it is. This sort of essence is at issue, for example, if we are dealing with questions of personal identity. Is this man now the same man as that man 30 years ago? The kind essence of a thing, on the other hand, is the set of its properties in virtue of which it is a thing of the kind it is. Of these two conceptions of essence, the most important one, from the point of view of scientific understanding, is the kind essence, since science is much more concerned with kinds than with individuals. Consequently, when I speak about the essences, or essential properties, of things, I should always be understood as talking about their kind essences unless I specifically indicate otherwise. The essence of a copper atom, for example, will be just the set of its properties in virtue of which it is a copper atom, and which it could not lose without ceasing to be a copper atom. It is not the set of properties in virtue of which it is the particular thing it is.

Aristotle’s concept of final cause – that is, that for the sake of which a thing exists – has no role in the new essentialism. The parts of animals do not exist for the sake of the animals of which they are parts, as Aristotle believed, nor organisms for the sake of the ecological systems in which they are found. Nor do modern essentialists conceive of the world as a grand teleological system in which the parts exist for the sake of the whole. However, modern essentialists do believe that things may have potentialities for development, or have inbuilt behavioural dispositions of one kind or another. Indeed, they believe that all things belonging to natural kinds have at least some such dispositional properties. So the modern essentialist’s world is not as organismic as Aristotle’s world, and it is never true to say that its parts exist for the sake of any greater wholes. But it is an integrated world, nevertheless, in which things are intrinsically disposed to interact with each other in various ways, depending on their essential natures.

Today’s essentialists suppose that the basic dispositions of things to interact with each other in the ways in which they do derive from the intrinsic causal powers, capacities and propensities of their most fundamental constituents. They suppose that these causal powers, and the like, are among the essential properties of things of these kinds, and therefore properties that things of these kinds have necessarily, since they could not possibly fail to have them, while yet being things of these kinds. Electrons, for example, are necessarily charged particles. That is, they are necessarily disposed to generate and respond in certain ways to electromagnetic fields. If a particle lacked this causal power, essentialists say, then, whatever else it might be, it would not be an electron. So, there is at least this affinity between the new essentialism and the old. According to the new essentialism (as well as the old), the essential properties of things may include their potentialities: their dispositions to act or react in various ways, depending on their circumstances.

Passivism denies this possibility. If things are essentially passive, as defenders of this view insist, then nothing can be intrinsically disposed to act in any one way rather than any other. Some things, in their special circumstances, might be disposed to behave in some ways rather than others, but only because the laws of nature happen to be as they are, and the things happen to be in the states in which they are. Change either of these conditions sufficiently, and they would no longer be so disposed. Hence, according to passivism, the dispositional properties of things are never determined just by their intrinsic natures.¹ Remember, the laws of nature are not supposed to be immanent in things, as essentialists believe, but externally imposed on them. Remember, too, that material things are supposed to be essentially passive, and so incapable of having any intrinsic dispositions. So, how a thing is disposed to behave can only depend on its passive, non-dispositional properties, and on what the laws of nature happen to be. Any dispositions that material things might have must therefore be wholly dependent on the passive states they are in, and on the laws of nature as they apply to things in those states.

Modern essentialism works with a much stricter conception of natural kinds than the old Aristotelian theory. In Aristotle there is the idea of things existing by nature, and it is evident that Aristotle believed that different individuals could have the same nature, since most of the essences he discusses are the essences of kinds of things, rather than individuals. So he is clearly committed to the existence of natural kinds in something like the modern sense of this term, and to the view that such kinds have distinctive essences. But in Aristotle there is a certain looseness about membership of a natural kind, and properties that are said to be essential to a kind may occasionally not be present. A man may lack rationality, for example, even though rationality is said to be essential to human kind. Modern essentialists would not accept such looseness. They would insist that any two members of the same natural kind must be identical in all essential respects. Moreover, they would insist that the essential properties of a thing be properties or structures in virtue of which it is a thing of the kind it is, and which it could not lack, or lose, while still being a member of the kind. Essentiality implies necessity in the strict sense of metaphysical necessity.

Metaphysical necessity is one of several species of necessity distinguished by essentialists. These species of necessity do not differ from each other in strictness, for none of them allows any possible exception. The other species of necessity that are commonly recognized are formal logical necessity and linguistic (i.e. analytic) necessity. Propositions that are necessary in any of these strict senses are true in all possible worlds. That is, they are such that not even God (even if He should be an omnipotent being) could create a world in which any of them are false. The different kinds of necessities differ from each other in the manner in which they are grounded.

Formal logical necessities are grounded in logical form, that is, in the meanings of the connectives and operators of the language. Thus if a statement is formally logically necessary, then it is true under all interpretations of its non-logical terms. The proposition that horses either exist or do not exist, for example, is formally logically necessary. Substitute any other name for “horses”, and you still have a necessarily true proposition. So horses can be interpreted as any kind of thing you like, and this proposition will still be true.

Linguistic or analytic necessities are sentences that are true in virtue of the meanings of words, and these are also true in all possible worlds. But they are not true under all interpretations of their nonlogical terms. On the contrary, their truth derives from the conventions of language, and is therefore strongly dependent on how the non-logical terms of the language are understood. The sentence “A bachelor is an unmarried man”, for example, is an analytic sentence of English, and this English sentence must be true in any world in which it is significant. Of course, there might be worlds in which there are no men, or where there is no institution of marriage, but it would still be true, vacuously true,² even in these worlds, that a bachelor is an unmarried man; it is just that we should have no use for this part of the vocabulary of English in describing such a world.

Metaphysical necessities are propositions that are true in virtue of the essences of things. Of course, if one does not believe that there are any natural kinds, or if one does not accept that things have essential natures, then one will not believe that there are any metaphysical necessities. But for an essentialist the concept of metaphysical necessity is fundamental. To explicate the concept of metaphysical necessity, essentialists distinguish between “real essences” and “nominal essences”. The real essence of a thing of a given kind is that set of its properties or structures in virtue of which it is a thing of that kind. The nominal essence of a thing of a given kind is that set of its properties or structures in virtue of which it is described as a thing of that kind. The two concepts, although formally similar, are really quite different. The nominal essence of a thing depends on what distinctions we care to make, and how we choose to make them. It thus refers to how we classify things in the world, and to the language we use to mark the different classes. But the real essence of a thing of a given kind is independent of our conceptualization of reality, and also of the language we use to describe it, for the real essences of things refer to their natural classifications, and these have to be discovered by scientific investigation.

Consider the proposition that water is H₂O. The fact that water is essentially a compound of hydrogen and oxygen was discovered in the eighteenth century, and its molecular formula ...

Table of contents

• Cover
• Half Title
• Title
• Copyright
• Contents
• Introduction
• 1 Essentialist Philosophies of Nature
• 2 Empiricist and Realist Perspectives on the World
• 3 Properties and Relations
• 4 Powers and Dispositions
• 5 Laws of Nature
• 6 Natural Necessity
• 7 Philosophical Implications
• 8 Wider Implications
• Appendix
• Bibliography
• Index