Life In Plants and Animals

radicalacademylogoThe Philosophy of Man
A brief introduction to rational psychology

Adapted from various sources and edited
by Jonathan Dolhenty, Ph.D.

Part Two: Life in Plants and Animals

Life as it appears in living bodies is sometimes described as the capacity for self-perfective movement or activity. Sometimes this brief description is further shortened, and it is said that life is self-motion.

The philosophic science of ontology tells us that anything moved is moved by something other than itself (see Being and Existence: A brief introduction to ontology). It would seem at first glance that self-motion is a contradiction and an impossibility. But the phrase does not mean that the living body moves itself into existence, or sustains itself there, or equips itself for its activity. Like other creatures, it depends for its being and is activity upon a creator, preserver, and concurrer. But, granted that it is created, preserved, and sustained in function, the living body tends by its activity to express, develop, or perfect itself. In this the living body is distinct from the nonliving body, all activity of which is transient. Perhaps it would be a just revision of the brief description of life given above, to say that life, in living bodies, is a capacity for immanent activity.

Life in living bodies is a capacity for activity, and an exercise of this activity. As a capacity it is called life in actu primo, that is, life in first actuality, or life in basic fact. As the exercise of life-functions, it is life in actu secondo, that is, life in second actuality, or life in actual exercise.

Now, the capacity for life-functions or vital operations is entirely due, in living bodies, to the presence of a substantial principle, a life-principle, a soul, a psyche. Indeed, it is accurate to say that life in actu primo or in basic fact is the soul. For the soul is that actuality whereby the body is alive and can exercise vital operations. The soul or psyche or life-principle is a substance (incomplete in lesser bodily beings than man) which is substantially joined to the body-substance. Indeed, the soul is the substantial form of the body, and is therefore the substantial principle which make the body exist as a living body of its specific kind. The soul is substantially united with the body in such a way that the result is a single living thing, a single if compound substance. (See The Theory of Hylomorphism for more information about substantial form.)

Life is essentially different from nonlife. A living body is not merely a more complex thing than a nonliving body; it is an essentially different kind of thing. Note the following points of difference between living bodies and nonliving bodies:

  • Origin: Living bodies come from parent-bodies, immediately or mediately; they are of the same nature as the parent-bodies. Nonliving bodies come by physical addition or partition, or by chemical fusion, from other bodies, but not by vital generation; and often (as in water generated from hydrogen and oxygen) the generated body is not of the same nature and essence as the generating bodies.
  • Growth and Decline: A living body grows by multiplication of cells into a determinate kind of organism, and to this end it exercises the operation of true nutrition. Nonliving bodies have no true immanent growth, but “grow” by accretion or addition of elements laid on outside (as in crystalline growth or the growth of a snowdrift). Living bodies run their course and then break down and decay, losing all their capacity for vital operation. Nonliving bodies tend to remain stable in equilibrium, and when they are worn down and dissolved this is due to outer agencies, not to the breakdown of an inner substantial principle.
  • Structure and Operation: A living body is cellular in structure. Cells are built up, by an inner drive, into most varied parts or organs which cooperate in the marvelous unity of an organism. Nonliving bodies are not cellular, nor are their activities immanent; they are built up of homogeneous parts without interdependence or organic unity.

Now it is manifest that bodies which exhibit such fundamental differences in origin, development, decline, structure, operation, are not mere varieties of one kind of thing. They are things essentially different; since they are essentially different substances, they are substantially different. And this is proof sufficient that life cannot originate in nonlife through an added complexity of structure to a nonliving body by mechanical, physical, or chemical activity. Life comes from life and a living body comes from living bodies and ultimately from the First Cause or creator of life and living bodies.

Life in living bodies manifests a scale or gradation. There are three types of such life, and these stand related, not like steps in the same stairway, but like three sets of parallel stairs. For the three types are essentially different; one is not merely a more perfect form of another. Yet the second type has all the perfections of the first, plus its own specific perfection. And the third has all the perfection of the second, plus its own specific perfection. These grades of life are called vegetal or plant-life, sentient or animal-life, and rational or human life. Life in living bodies is, therefore, at once of three kinds and of three grades. We assert the essential difference of the three grades of life in living bodies for the compelling reason that each superior grade of life has perfections or operations which are essentially beyond the reach of the lower grade or grades.

As we have said more than once, life in a living body is due to the presence of a substantial principle of life or a soul. The mass or material bulk of a body does not account for its life. The structure of a body as an organism does account for life-activity, but this very structure has to be built according to a set plan before it is operative, and this building is due to an indwelling substantial principle which is not that thing which is built; even after building, the organic structure does not explain its permanence or its actual functioning, for in itself, it is only a structure suited for its functioning, and a substantial activating principle is still required to explain the fact that it does actually exercise vital operations. There must be, in a word, a first informing and substantial principle which makes the body alive; which determines the body as plant, animal, or man; which holds the body in its organic and functioning unity. This substantial principle we call the soul.

Modern scientists do not like the word. They prefer psyche, or entelechy, or bathmic energy, or vital direction, or even “the something over.” But philosophy cannot pause to quarrel about words. We call it the soul, and we say that it is the substantial principle of life which constitutes the organism and is substantially fused with the organism in the unity of a living body, and that it is the root of all operations of the living body, even those activities which it uses as instruments and which are in themselves mechanical or physicochemical.


Dr. Jonathan Dolhenty was the Founder and President of The Center for Applied Philosophy and the Radical Academy, and is Honorary Philosophy Editor at The Moral Liberal. The Moral Liberal has adopted these projects beginning with a republishing and preserving of all of Dr. Dolhenty’s work.


The Moral Liberal recommends: Great Books of the Western World