[This addendum is to "Ontological Hierarchy of Differentiation—Life
I wrote in the introduction to the article on life that the physical relative qualities account for all the characteristics of material existence called physical. "What they cannot account for is that aspect of material existence called life."
In one of her journals, The Journals of Ayn Rand, "Part 4 - Atlas Shrugged, 11 - The Mind On Strike: April 26, 1946," Ayn Rand wrote:
"The supposition of man's physical descent from monkeys does not necessarily mean that man's soul, the rational faculty, is only an elaboration of an animal faculty, different from the animal's consciousness only in degree, not in kind. It is possible that there was a sharp break, that the rational faculty was like a spark, added to the animal who was ready for it—and this would be actually like a soul entering a body. Or it might be that there is a metaphysical mistake in considering animals as pure matter. There is, scientifically, a most profound break between the living and the non-living. Now life may be the spirit; the animals may be the forms of spirit and matter, in which matter predominates; man may be the highest form, the crown and final goal of the universe, the form of spirit and matter in which the spirit predominates and triumphs. (If there's any value in 'feelings' and 'hunches'—God! how I feel that this is true!)"
I want to emphasize these words: "... it might be that there is a metaphysical mistake in considering animals as pure matter. There is, scientifically, a most profound break between the living and the non-living.
Although she did not develop these thoughts, because she never did write anything ontological, her supposition is correct, which of course is what the article this is an addendum to attempts to explicate. That explication is somewhat formal and I want to address the subject life, and its nature somewhat differently here.
Life, An Attribute
Whatever life is, it is that which differentiates those things which are living organisms from all other non-living things. It is the attribute of a thing that makes it an organism.
At the physical level life manifests itself as a process that is self-sustained, and determines the behavior of an organism as living entity. The living behavior of an organism cannot be understood or explained apart from the life process. The living behavior of an organism sustains the organism as an organism.
From a physical perspective, only the physical aspects of that process can be directly observed, that is, science can only deal with those aspects of life that are physical. The sciences that study the physical aspects of an organism are biology, anatomy, neurology, and biochemistry, for example. What science cannot study, are those aspects of the life process that are not physical, which are the attributes unique to living organisms because of their life, not their physical characteristics, which cannot give rise to them.
1. Self-sustaining nature.
2. Unique response (sentience)
Though addressed in the original article, I want to expand on each of these somewhat.
Non-living physical things do not sustain themselves. They may remain for long periods of time the kind of thing they are if substantial enough (like a diamond) or quickly change into something else (like a drop of water). But no physical thing acts to maintain itself as the kind of thing it is. All its behavior can be explained entirely in terms of physics and chemistry.
An organism's behavior, as an organism, must sustain itself as the kind of organism it is, else, it ceases to live, that is, to exist. There can be no physical explanation for why anything's behavior should be to sustain itself, which means, there is no physical reason for life.
All living things must have some level of sentience. It may not be (and cannot be in the simplest organisms) what we mean by sentience in the more complex organisms, but it must perform the function of sentience, which is exhibited by two attributes of all living behavior: detection and discrimination. Only living organisms have these attributes and they both cease if the life process ceases. We call the behavior associated with these attributes, "response to stimuli."
A living "response to stimuli" is unlike a mere physical reaction precisely because it requires the two characteristics, detection and discrimination. A mere physical reaction does not require either.
By detection is meant, an organism must be able to "sense" or "be aware" of some internal or external event, entity, or substance. By discrimination is meant, an organism must be able to distinguish between different detected events, entities, or substances, which will determine its response to it.
If an organism could not detect that which it reacts to, its actions would be mere physical reactions, not living responses. If an organism could not discriminate between different stimuli, its response to all stimuli would be the same, or random, and therefore useless to the organism's survival.
While science will be able to discover the physical (chemical, electrical, etc.) aspects of an organisms behavior, the fact that a response is only possible if the organism is alive means that whatever aspects of the response are physical, they cannot be sufficient to explain the living aspects of that response, or how the life makes those responses possible.
For merely physical events, there is no connection between the cause of the events and the consequences of them, except the physical events themselves. For living behavior, however, both the cause of the behavior (or what makes it possible), and the consequence of the behavior (what it produces) is the same thing, the life of the organism. There is no other reason for living behavior than the sustaining of the life which makes it possible.
[Note: The behavior of organisms extends beyond that which merely sustains the life of organisms, especially for the higher organisms and includes all that fulfills the requirements of their nature, including the enjoyment of their lives. Here, it is only that which distinguishes living behavior from non-living actions that is meant.]
There is no reason for any physical behavior except the laws of physics, but the life process has an end, a "purpose," which is the life process itself, and without that end, there would be no life process.
Life, A Thing
Life is an existent, a thing, but it is not physical, therefore it must not be thought of as an entity, or a substance, but an existent uniquely identified by its attributes or qualities. Everything that exists is identified by its attributes and qualities. Physical things are identified by their physical qualities, such as size, weight, color, shape, or temperature. Life is not physical, and therefore has no physical attributes or qualities.
The attributes of life are those just discussed, that which differentiates living organisms from non-living physical entities which manifests itself as a self-sustained process that is responsible for an organisms sentience and purpose.
Life is not physical, but it cannot exist independently of a physical organism of which it is the life. It is not supernatural, but a perfectly natural aspect of reality, the aspect that is the life of all living organisms.
As a thing, life is not something "added to" the physical, like a spirit entering into non-living matter, giving it life. It is very much the opposite, in fact. Life always takes on non-living matter and makes it living by making it part of the organism it is the life of. Life grows, not by moving out into more and more non-living matter, but by including more and more non-living matter in itself.
As far as we know, life only comes from life, and the growth and expansion of life has only one source and cause, which is life itself. It is not within the province of philosophy to speculate about the origins of things, or even if there are origins. (Although it is philosophically correct to deny the possibility of nothingness.) It is the purpose of philosophy to discover the nature of what is, not how it got here.
[Note: I've been told one reason to study origins is to help understand how things are now. That might be if we had a record of how things got here first, like the auto-mechanic asking the customer, complaining of a rattle, if he has hit any really bad bumps recently. For those interested in how things got here, there is only what is here to go on. First, what is here must be understood and perhaps some things might be discovered from that how they got here. Trying to figure out the nature of things that are here, from how they got here, is simply backwards.]
In all of my discussion of the nature of life, there is still something left out, which Rand was moved by, that, "profound break between the living and the non-living," which poets seem to notice, and some philosophers, but not so many scientists, although some do, especially those in the field of medicine.
In this universe there is life, even if the only life in it is in this tiny speck in the universe we call earth. Without that life we would not be either. I do not believe existence is contingent, so the universe that is what it is, and could not have been anything else; but we might be able to imagine a universe without life, or at least say it, but what would that universe be? If there were such a thing, it certainly wouldn't matter—nothing matters if there is no life, because there is nothing for it to matter to.
The break between the merely physical and life is indeed profound, in ways perhaps only a poet can rightly express, but this poor philosopher at least recognizes that, as astounding as the physical universe in all its grandeur is, without life it is a pointless show in an empty theater that would never be seen or matter. But the universe does have a point, because there is life in it, and it is astounding, because we are in it to be astounded by it.
Why Is This Important
The common view of materialism, which is really physicalism, meaning that all that exists is the physical and that science is therefore the only tool for the study of everything, is a mistake. Most philosophers have been reluctant to make any case for the non-physical, however, first because they have assumed the only alternative to the physical is the supernatural, and that in the realm of mind, a non-physical consciousness must result in a kind of dualism, such as mind vs. matter, for example.
Neither of these assumptions is correct, however, which is why I have written extensively about the nature of life, consciousness, and volition to demonstrate they are not physical, and cannot be understood in terms of the physical, but are perfectly natural and require no "dichotomies" of any kind.
In a summation of the remainder of my ontology, volition, consciousness, life, and physical matter are all attributes of the same natural existence or reality. Where they exist, they are inseparable, but not everything has all these attributes. Men have them all, volition, consciousness, life, and all the physical attributes. All the higher animals have consciousness, life and the physical attributes, and the simplest living organisms have life and the physical attributes only. The mere physical is missing all the others, and can be studied entirely in terms of the physical sciences.
[I intend to do a similar lighter treatment of consciousness and volition similar to this on life. In the meantime you may refer to the more formal article, "Ontological Hierarchy of Differentiation—Consciousness, Volition," if you choose to.]