Axiology is the name of the field of philosophical inquiry that concerns the nature of values and value judgments. As noted earlier, there are many kinds of values, aesthetic, medicial, commercial, and functional or instrumental values of various kinds. The basic distinction is between intrinsic and derived values. A bio-centric axiology is a theory of value that takes Life as the basis of intrinsic moral value, and assumes that all of the various kinds of derived value acquire their values in relation to living beings. One can understand the bio-centric axiological perspective from ecological, evolutionary, and ontogenetic perspectives.
The Ecological View of Intrinsic Moral Value
When Aldo Leopold's classic work "A Sand County Almanac" appeared in 1949, the ecological crisis that human activities were producing on Earth had only become apparent to a few people. Because of his love for the land, and his work with the U.S. Forest Service, Leopold had a better view than most people of the ways in which humans were destroying the land because of their indifference to its moral status. He hoped for an enlargement of the human sense of moral community to include a "land ethic" that would include a regard for preserving the "integrity, stability, and beauty" of the land for its own sake, and not only for the economic value that certain portions of land, or certain species of plants and animals might have for human beings. He wrote that, "All ethics so far evolved rest upon a single premise: that the individual is a member of a community of interdependent parts. His instincts prompt him to compete for his place in that community, but his ethics prompt him also to co-operate….The land ethic simply enlarges the boundaries of the community to include soils, waters, plants, and animals, or collectively: the land" (Leopold, 1948, 203-4).
It is important to appreciate that for Leopold, the land is not merely soil;
...it is a fountain of energy flowing through a circuit of soils, plants, and animals. Food chains are the living channels which conduct the energy upward; death and decay return it to the soil. The circuit is not closed; some energy is dissipated in decay, some is added by absorption for the air, some is stored in soils, peats, and long-lived forests; but it is a sustained circuit, like a slowly augmented revolving fund of life. (216)
Land is used here as a collective noun, like "furniture" which encompasses a number of distinct types of things. But unlike furniture which is just a collection of different kinds of man-made inanimate objects, the land supports a biotic community, a place of life. Without its living members there would be no energy circuit and the soil would be as dry and lifeless as dust on the Moon, the Earth's barren twin. The energy of the Sun reaches the Moon just as it reaches the Earth, but there it is only reflected back out into space. While on Earth some of this solar energy is captured and converted into living forms.
In order to understand the land in this sense, one needs to understand ecology, but this turns out to be very difficult to do. We humans are only beginning to comprehend the exquisite balance that sustains biotic communities in different regions and locales of the Earth and under its seas. Like the evolution of our scientific understanding of ecological systems, Leopold thought that a land ethic would evolve once we humans "quit thinking about decent land use as solely an economic problem," and began to examine the land "in terms of what is ethically and esthetically right, as well as what is economically expedient" (224). He offered as a guide to what "right" means in this context when he wrote: "A thing is right when it tends to preserve the integrity, stability, and beauty of the biotic community. It is wrong when it tends otherwise" (224-5).
Since Leopold's time significantly more human beings have come to appreciate the wisdom of this perspective and have come to regard biotic communities, the land in this sense, as something worth preserving for its own sake. By adopting this moral response to the land, we humans create and extend the boundaries of our moral community. We do so in part because we have come to understand that we ourselves are part of the land and draw our energy from the same fountains of energy that support other living beings, so that when we harm the land, we harm ourselves as well. School children now learn this, but few fully understand it.
But we do no need to think that the elements of a biotic community have equal moral status. Soil and air, water and sunlight, for instance, which are necessary for life, are not themselves things which are intrinsically valuable. Some people think that the microbes and bacteria are intrinsically valuable because they are living things, and more people may admit that the plants and animals which nourish themselves on these microscopic creatures have some kind of moral standing. But these remain controversial views.
On the other hand, most people will readily agree that they themselves have intrinsic value. Each of us, from an egocentric point of view, regards our own life as intrinsically valuable, and we have come around to understanding that we must, to be consistent, universalize this idea and regard all other human being as "ends in themselves," as things which have their own good and to whom moral obligations can be owed for their own sakes. This understanding is what shapes the idea of global human moral community based on the ethics of human rights
However, under the conventional ethical theory most humans accept, human beings are the only creatures that are ends in themselves. The value that all other living things on the land in the sea and in the air have is only an instrumental value, a value for us, not an intrinsic value. This homocentric (human-centered) perspective is what most humans use to understand the moral domain. From this perspective we need inquire only about the usefulness or utility of other members of the biotic community for us, their ability to satisfy our appetites and desires. When we see the moral world in this way, other living beings have no intrinsic value at all; their value is only instrumental and is derived from their utility to us. Since most other living things have little or no use for us, we tend not to care about them.
But this homocentric (or anthropocentric) view is cock-eyed from the ecological perspective. Human beings, standing as we do at the top of the food chain, may represent the apex of the biotic pyramid on Earth, but we are not its base, nor its intermediate levels. We have the moral stature that we do because we stand upon the backs of all of the other creatures of the land and sea, and along with them upon the Earth itself rotating on its axis and revolving around the sun. Moral stature is built from the bottom up, not bestowed from the top down. We humans have the moral stature we do because we stand upon a pyramid of value which sustains our existence as a species. That pyramid of value is what Leopold called the Land, the living Earth, which encompasses the land and sea and air and all of the biological forms that inhabit them. As living forms human beings have intrinsic value, but we only have the moral stature we do because we stand upon a high plateau on the great pyramid of life.
The Evolutionary View of Intrinsic Value
The biological basis of intrinsic moral value can also be understood from the evolutionary perspective. The human beings who are now living are the growing end of an evolutionary process that began billions of years ago when life first appeared on the planet Earth. Our present understanding of the evolutionary epic which led to our existence while limited and incomplete enables us to understand that through a coincidence of fortuitous circumstances life was somehow able to spring forth from the Earth. The conditions of the primordial planet, its atmospheric composition, the abundance of heavy atoms born from exploding stars in its soil, the presence of water, and the continuous influx of energy from the sun, somehow enabled living forms to arise. The first of these life forms, primitive microbes, such as cyanobacteria, discovered how to convert sunlight and carbon dioxide into life sustaining energy, producing oxygen as a byproduct, and so began an evolutionary process that over billions of years produced the manifold living forms that now inhabit the planet.
Each living link in this great evolutionary chain of being possessed intrinsic value because it contained the spark of life, the sacred fire. This value was passed onto its progeny and from them onto theirs by means of biological inheritance encoded in the DNA molecules that all life forms have. As life became more complex and multi-cellular animals and plants can into existence these living things increased in moral stature. The emergence of sensation and intelligence in some creatures further enhanced their stature. And finally, at the end of one branch of the great tree of life, homo sapiens came forth into the world with the power of language and thought. But the capacity for language and thought is not the basis of our value; rather it is the product of a process of cosmic evolution through which living value grew slowly over billions of years. We are only the inheritors of this intrinsic value, not its creators.
The Ontogenetic View of Intrinsic Value
One can grasp this conception of intrinsic value in another way. From the ontogenetic perspective each of us now living grew from living seeds, ova and sperm, which when joined together somehow "knew" how to divide and multiply in order to form a new human individual. Those living seeds carried the spark of life inherited from the evolutionary history of the species and, by combining, began a new cycle of life. The fertilized embryo, then, has some intrinsic value, it was valuable in itself, because like other living things, it inherited its value from its ancestors, and perhaps will one day pass that living value onto its progeny.
But the embryo's moral stature is relatively low at this stage in its development compared to other moral patients. It lacks sentience and intelligence, it cannot think or speak, and is not yet a member of human society. Yet, unless it's growth is interrupted, the process of gestation enables the embryo to continue its ontogenetic development by drawing energy and nutrients from its mother's body. As a fetus develops in utero it grows in moral stature as well as in size and functioning. While birth marks the entry of a new member into the human moral community, the growth process continues through infancy, toddlerhood, childhood, adolescence, and into adulthood. The process is itself gradual and seamless and as the individual human being takes shape and grows into an adult its moral stature increases. As adult human beings we have come to have full moral status as moral agents, a moral stature that puts us on a high moral plateau. But we have attained this stature only because we have inherited the value inherent in each of the earlier stages of our individual existences, our earlier living incarnations each of which had its own moral status based, at least in part, on its intrinsic moral value.
One of the great achievements of modern ethics has been to recognize that the equal intrinsic moral value of all human persons. The ethics of human rights creates a single status moral community in which all persons occupy a single moral plateau in which we are all "equal in dignity and rights." This achievement has been the result of a long historical struggle, one which is yet not completed, to secure universal recognition of the inherent dignity, the intrinsic moral value, of all human beings.
But this great egalitarian achievement still depends upon a homocentric axiology. A homocentric axiology which take human beings or rational moral agents as the only things in the universe that have intrinsic moral value stands the living pyramid of intrinsic value upside-down. By assuming that only human beings possess inherent worth it reduces all other living beings to mere things which exist for our sakes, whose value is wholly derived from their utility in relationship to human interests.
But when we invert the value pyramid and place it back on its proper base we see that the moral plateau we humans occupy stands on top of a mountain of life, and at the growing end of a chain of living things each link of which has (or had) its own intrinsic moral value. When we understand the existence of human beings on Earth from the ecological, evolutionary, and ontogenetic perspectives, or, for short, from a biocentric point of view, the intrinsic value that human beings have is seen to be a function of our position within the broader biotic community that has evolved on Earth. From this bio-centric perspective we do not give other living things their value; Life gives intrinsic value to us.