From the point of view of Life itself, as a branching tree of evolving life forms, human life is just one other form it takes, and no one form of life - plant, animal, or human - is any more or less valuable than any other.

And life largely feeds upon itself. Animals kill and consume plants and animals, and plants in turn fertilized by the decomposed remains of plants and animals. Life is always destroying and consuming and reconstructing itself.

Humans may value themselves above every other form of life, but then every form of life always values itself above every other. And individual humans usually value themselves above all other humans.

Humans have to eat food to live, and this food is almost entirely plant and animal life. For humans to go on living, they have to kill and eat plants and animals. And yet if, from the point of view of Life, all life is equal in worth, why should plants and animals sacrifice their lives for the sake of humans, rather than humans sacrifice their lives for plants and animals?

Idle Theory's approach to this problem is to compare the total of what is lost with the total of what is gained, and to prefer those outcomes which gain more life than lose it. If a man lives for 70 years, and is 10% idle during that lifetime, then the value of his life to himself is 7 years. And if a man lives for 70 years, and is 90% idle during that lifetime, then the value of his life is 63 years. And the value of a man's life, at any point in it, is its remaining idle time, given some life expectancy. And so, half way through a a 70-year-long, 90%-idle lifetime, a man's life is worth 31.5 years. And exactly the same applies to any other living creature, plant or animal.

To kill some creature is to deprive it of its remaining idle time. And for one creature to eat another creature is to gain some period of idle time, and retain the possibility of living out a natural lifespan.

And so in weighing up whether a sheep should sacrifice its life to allow a man to live, or whether a man should allow himself to die rather than kill and eat a sheep, the gains and losses of idle time associated with the two alternatives need to be found.

First we need to find how long plants and animals live. Compared to a human life expectancy of 70 years, the lifetimes of micro-organisms may be very brief. Mayflies live for one day. Grasshoppers live for one summer. Female black widow spiders live 3 years. Frogs may live 3 years. Robins may live for 2 or 3 years. Chickens live for 7 years. The natural lifespan of sheep is 12 years, and of pigs 15 years. Owls live for 20 years. Cats can live for 20 years. Most dogs for 10 years. The natural lifespan of cattle is 20 years. Dolphins live 25 years. Sperm whales and elephants live for about 65 years. Birch trees live about 40 years. Saguaro cactus live for about 100 years. Hemlocks can live to 400 years. Sequoia trees can live for 2000 years. Bristlecone pines can live 5000 years. In general, it seems that the larger any creature is, the longer it lives. (All these figures have been grabbed from various internet sources).

So, taking the natural lifespan of sheep as 12 years, and of humans 70 years, and assuming both are perfectly idle, the resultants of the two courses of action can be compared:

Of the two alternatives, one results in a loss of 70 - 12 years, and the other a gain of 70 - 12 years. And so, it is best, in that it provides more life, if sheep die than rather than humans.

But then, if a 69 year old man kills and eats a 6 month old lamb, there is a net loss of idle time.

The unit of life: individual or cell?

And we may introduce a further complication into this calculation by arguing that many living creatures are composed of some number of cells, and that the fundamental unit of life is not a man or a sheep or a cabbage, but the individual cells that make up these different life forms. And so, if the number of cells in any multicellular organism roughly corresponds with its weight or mass, then the the value of any life to itself, V_i, is not simply its idleness multiplied by its remaining lifetime, but its mass, M, times its idleness, I, times its remaining lifetime, L_r.

V_i = M.I.L_r

A Natural Order?

And using this measure, there emerges a scale of relative values, with small, short-lived, busy creatures at the the bottom, and large, long-lived, idle creatures at the top. And it is in this natural order of things that the the large and long-lived consume the small and shortlived.

And to a great extent the natural world would appear to follow this order of things, with large animals consuming smaller ones, and grazing animals consuming small plants and leaves. And where a predator like a lion kills and eats a larger animal, very often these will be the oldest approaching the ends of their lives. And if it kills and eats the young calves of these large animals, it is counterweighed by the small mass of these calves.

This natural order breaks down when, for example, bacterial disease decimates a population of large animals. In this case, the small and shortlived kills the large and long-lived. If the natural order were to be inverted, all life would be composed of shortlived unicellular organisms.

In this particular natural order, human beings aren't at the very top, but only somewhere near the top. Since elephants live to a similar age as humans, but are much larger, elephants are more valuable than humans. And large and long-lived oak trees are more valuable than either elephants or humans.

And if there is a moral rule that comes out of it, it is that it is permissible for humans to kill and consume relatively small and short-lived plants and animals, but impermissible to kill and consume relatively large and long-lived plants and animals - like elephants and whales and oak trees and sequoias and bristlecone pines.

And also, it is always impermissible to wantonly kill any creature, because in this case there is only loss of life, and no corresponding gain. Or, it is permissible to kill insects that infest a house, and consume or ruin food and clothing and furniture, thus costing the human occupants time and trouble. But it is impermissible to kill the same insects living in the wild, where they pose no threat.

Objections

Now there may be a great number of objections to this way of considering the relative values of living creatures.

For example, how do we know what the natural lifetime of a creature might be? In one environment, a plant may be long-lived, but in another short-lived. So how can we say what is a natural lifespan or life expectation?

Again, human life expectancy varies from circumstance to circumstance. In Europe in the 15th century, human life expectancy was about 40 years. And at present, thanks to improved nutrition, easier work, and advances in medicine, it is more like 80 years. So what is a natural human lifespan?

And to what extent are European humans long-lived because they inhabit warm houses and wear warm clothes, while most animals - apart from household pets - do not? And to what extent are animals and plants short-lived because humans kill and eat them, or otherwise make their lives difficult?

And then again, are we to suppose that lions make ethical calculations about which animals they will or will not kill? Is it not more likely that lions kill that which is easiest to kill, and which provides the most sustenance? If lions don't kill adult elephants, it is perhaps not for want of doing so, but inability.

Or again, is a large man more valuable than a small man, assuming that large men are made up of correspondingly more cells? Are fat men more valuable than thin men? Are relatively large males worth more than relatively small females? Are old people less valuable than young people? Do we not cease to regard all men as equal, if we regard them as a society of cells, rather than unique individuals?

And if we are to take cells as the unit of life, should we not also take into account the fact that in, multicellular organisms, cells are continually reproducing and ageing and dying, so that a man aged fifty is not composed for the most part of the same cells that he was composed of at the age of ten? And again, not all cells have equal lifetimes: brain cells are very long-lived, but the cells of the skin and the lining of the gut are very short-lived.

And if a man is faced with the alternative of either killing and eating a whale, or dying of starvation, is he really going to allow himself to die of starvation, on the principle that the whale is larger and more naturally long-lived than him?

Very roughly, the rule might be to allow living creatures to live natural lives to somewhere approaching their natural lifespan before taking their life. And in general, it is the practice of farmers and foresters to do something along these lines. And indeed both, in acting to ensure that trees grow healthily, and animals are fed and watered and protected from predators, act to increase the idleness of the creatures they tend. And if there is revulsion at the battery farming of chickens, it is because these animals are not permitted to enjoy any sort of natural life, but kept cooped up in cages, or crowded together, without any respect for their lives.

If some living creatures are useful to humanity as food or building material, there are other creatures which are either useless or dangerous to humans. The bacteria of diseases, the weeds that grow in wheat fields, the locusts that destroy crops, the wolves that carry off sheep. And here it might be argued that shortlived bacteria and shortlived insects have little value in themselves, yet can do great damage to plants and animals and the humans that depend upon them, and that their destruction will entail little loss, and much gain to plant and animal and human life.

And then again there are forms of life which are of no great value to humans, nor any threat to them. Butterflies and tulips are of no value to humans (except for their beauty, which is a secondary ethical concern), and no threat. To destroy these is to simply destroy life and gain nothing from it. And therefore they should be let live.

In many ways, from the human point of view, there is a set of life forms which are valuable to them, another set which have no value, and another set which are disvalued. The first set includes cattle and sheep and goats and cats and dogs and wheat and barley and potatoes and oak trees and pine trees and the like. The third set includes bacterial diseases, aphids, locusts, rats, mice, wolves, lions, and tigers. And the second set comprises everything else. But while the third set is in some degree a menace, their lives remain valuable in themselves, and as human cultivation expands to remove their natural environment, humans ought to act to preserve them rather than exterminate them, leaving something for them to live on. For example, a farmer who keeps birds and insects off his plants by covering them with nets will produce a larger crop. But the birds and insects will have less to eat. Such farmers ought to give back a little of their abundant crop to support these birds and insects. And where they tend cattle and sheep, they ought to offer a few to wolves and lions.

And again, it should be impermissible to kill any living thing for purely secondary aesthetic purposes - because their plumage is beautiful, or their fur is soft, or their tusks and teeth can be carved into figurines, or their heads mounted on walls. For such killing only takes life, and neither creates nor sustains more life.

In some ways the system of values that seems to grow from this approach to the value of life finds parallels in a growing modern concern to preserve the natural environment, particularly longlived trees and whales and elephants. And it can be argued that it would be more efficient for humans to eat only plants such as rice and wheat, rather than cattle and sheep, because more food energy can be obtained through plants rather than animals. But the justification of many vegetarians for this is that animals are living creatures like us, and plants are not. But Idle Theory would make no distinction between plant and animal life, and simply declare that both are forms of life.

And indeed, it may find parallels in the past worship of holy trees and sacred groves, and the gift of offerings to predatory animals. Perhaps humans have always venerated longlived forms of life, and treated them with appropriate respect.

But also, human attitudes to other forms of life perhaps depend on human idleness. Busy humans are likely to be entirely careless of other life, including other human life. It is only idle humans who can take note of the world in which they live, the variety of its creatures, and have compassion for all life.

This approach to the value of life would suggest that 'mercy killings' are permissible. If someone is dying in great pain, it should be permissible to end that life.

And equally, in the case of abortion, early abortion simply kills off a few cells. And is less important than swatting a fly.

This essay only scratches the surface of large and important moral issues. But it perhaps points towards another way of thinking about the value of life in its widest context, beyond human life.