Science in Christian Perspective
What Is Life?
Department of Biology
Dordt College, Sioux Center, Iowa 51250
From: JASA 25 (June 1973): 41-44.In beginning courses in Biology the meaning of the term Biology is usually asked, and the typical answer explains that the Greek roots of bios and logos stand for the study of life. The next question is then, of course, What is life? But can we actually go out in search of life and expect to find it? And would we be looking for a thing, a substance, a force, or a series of reactions? Or maybe something less concrete? History indicates that just to ask these questions may mean that we are on the wrong track, as the time worn dualism of Vitalism vs. Mechanism bears out.
Is life nothing but the sum total of physical and chemical principles, or is life something more than or above these principles?
A Basic Dilemma
We have thus this basic dilemma: is life nothing but the sum total of physical and chemical principles, or is life something more than or above these principles? It should be pointed out, first of all, that this dilemma is not one of the Christian position over against the non-Christian. Both Christians and non-Christians are found in either camp, fighting shoulder to shoulder against people in the other camp. Now it appears that the vitalists and the mechanists are both partly right and partly wrong. Their positions have become polar ized in reaction to each other, not only in recognition of part of the created structural order, but also in objection to the violation of structural order by the opposing camp. The vitalists have correctly' recognized that life is more than simply a series of chemical reactions, while the mechanists have rightly seen that there is a physical basis underlying all life phenomena, and that a special, non-material substance is uncalled for. Yet, their formulation of the question, in terms of what life is, makes it in essence impossible for either camp to solve the problem.
Seeing some of the difficulty; inherent in the problem, the Neo-vitalists hava taken a new torn. Basing some of their arguments ms experiments with sea urchin eggs, which, when cut during the early' stages of embryologic development, still curled tip as perfectly normal sea-urchins, these men say that the germ cells develop as an 'harmonic equipotential system' in which all the elements have an equal disposition to direct toward the final result, in mutual harmonic cooperation. In the attempt to withdraw 'life' from the dominating rule of' the mechanistic concept of causality', the position is taken that equifinality contradicts the physical laws and can he accomplished only by a soul-like vitalistic factor, called entelechy, which regulates these processes "in foresight of the goal" (i.e., the organism to be developed).
Countering this new position is Bertalanffv, for example, who says that equifinalitv is responsible for the primary regulability of organic systems, i.e., those regulations which cannot be based on predetermined structurer or mechanisms. This, of course, puts us back at the original dilemma of opposing answers to the question, What is life?, except that the sparring ground has shifted slightly. But the basic problem is not any closer to being solved now than it was in its earlier form.
We are still steeped in the sane problem today, and that it permeates our contemporary' situatioos and difficulties is exemplified very clearly' in the 1911 Time essay on "The New Genetics: Man Into Superman ", where the introductory paragraph poses the same old dilemma in these words: "Perhaps it was simply a matter of chance, a random throw of the molecular dice. Perhaps some greater, transcendent force was at work in the earth's prime al seas." In the ensuing pages the problem of "life" is dealt with almost exclusively no the presupposition that life can be defined "in the logical language of chemistry." So in essence we have made progress in the long search for that which is the essence of life.
A New Starting Point
As Christians we can of course not side wholeheartedly with either the vitalists or the mechanists. It is, therefore, not unfair to ask that we reconsider the entire question from a new starting point and that we discard not only the traditional answers but the original question as well. Obviously, if you ask the wrung question you can never arrive at the right answer.
Where do we go from here? We have to go all the way hack to the beginning and ask what Biology really is. Instead of saying that Biology is the study of life, it would he more accurate to say that it 5 the study of living organisms. Now we do indeed have a turning point, for our next inquiry as to where we can find living organisms is one we can deal with very concretely.
Whereas we were unable to find 'life', as such, anywhere around us, we have no difficulty recognizing living organisms, and find that, in the bargain, we also experience life, which is never found outside the context of living organisms.
There is a fundamental difference between all living things and non-living things, and this difference we are able to recognize ill our naive, everyday experience. Thus any ordinary person can infallibly sort the world around him into lifeless or inorganic, and living things. lIe will see that life is not just scattered all over, but exists only in individual organisms. This recognition is not a superimposition of order by our mind on a chaotic world, but a true recognition of the order which God created ill the cosmos. And we are able to recognize this order, although always imperfectly because of sin, because God created us with that ability, which is part of our being human.
The fact is inescapable that the biotic aspect is inseparably intertwined with the other aspects .... Yet it is the biotic which or recognize, and it is the biotic only which sets the organism apart as a living thing.
We are forced to admit the validity of our everyday experience, for if we deny
it we are in serious trouble. On what basis would we then accept the
the sky is blue, or that lead is heavier than water? And if we could not rely
on our experience, is there any' basis on which we can accept anything at all?
Our naive experience is, by and large, reliable even if our
understanding of what w e experience may have to he corrected by theoretical analysis.
The question is, therefore, not whether living things arc different from non-living things, but how they differ. If at thus point we say' that that which makes living organisms different from non-living things is "life" we will he right back at the dilemma we seek to escape, for our next question could then, again, he, What is life, a process, a substance, etc.? We should, instead, recognize that all living organisms have something which we all recognize, and which allows us to group them together as living beings, and this something we call the biotic aspect of the organism. There are several observations we can make about the biotic. First of all we must say that the biotic is irreducible, and in this respect is hike numbers, space and motion. I will say more about this subsequently. Secondly, we must see that the biotic cannot be equated with a machine. The concept of the animal (or man) being a machine was posited by Descartes already in the 17th century, where he thought in terms of a mechanical machine such as the clock. With increasing refinement of the machines invented, the model for an animal changed accordingly to a heat machine, to a cybernetic machine, and presently to a molecular machine which controls itself by means of its structures and configurations at the molecular level. But no matter how refined our machine may be, we are always left with the nasty problem of how the machine originated, of what re gu lates any deviations which may occur from the pattern for which it was programmed, and lastly of where to find a machine winch today could actually serve as a model for demonstrating the different metabolic or protoplasmic properties, and their organizational coherence. Thirdly, we can assert that the biotic is that which sets living organisms apart from the inorganic world. And that which sets them apart is not "life", but the fact that they are living.
If we now, as biologists, ask what makes an organism different from all inorganic things, we call to mind the fact that all living things are made up of the same unit, the cell. All unicellular organisms, like an alga or an ameba, are cells, while all multicellular organisms, whether plants, animals, or man, are made up of a number of different cells, We may also say that all organisms are made of protoplasm; i.e., the stuff of which cells are made. All cells have what we know as the protoplasmic properties, which are those functions which ss e can observe in all living cells, more in some cells and less in others, yet always present. All these functions can he summarized in the term metabolism, which includes respiration, digestion, growth, reproduction, assimilation, secretion, excretion, irritability, conductivity and contractility'. Besides these functions of protoplasm, we could list the organic constituents which are found in organisms and ss hieh are not normally found in organic things, as well as their dynamic organization which regulates the functioning of an organism in the full context of its living conditions. Although we can enumerate all these different constituents, properties and functions of an organism, however, the sum total of these is not equal to the organism. There are always more questions to he asked and to be answered about a living organism than we can enumerate in a list of properties or of constituents.
We can categorize the different types of questions svhich we can ask about an organism, and in analyzing what type of questions these are, we will also more clearly see what it is that sets inorganic things apart from living organisms. Some of the questions we may ask are of a strictly numeric nature, involving the number of sepals and petals of a flower, the number of toes on a paw, etc. The question here is always,
A living organism is an organism... because of its unique constitution and organization.
How many?, and is strictly on the arithmetic level. Another kind of
we can raise involves the spatial aspect of the organism, and here we ask about
size, relationship, as, e.g., in the question of the size of the internode on
a stem, or the relationship of the pancreas to the duodenum. The answer to this
type of question will not only require numbers but also a unit of distance. The
variety of questions in this category is obviously much richer than
in the first
category. The third category involves questions of a physical nature,
numbers and distance the element of time also enters in, and thus allows us to
express something about the forces, motion, speed, re
actions, etc., with which we deal. Physicists and chemists are asking questions
of this nature all the time, and those who ask these questions about
are of course the biophysicists and the biochemists. In the molecular biology
of today very many of the questions asked are of this nature. But although the
results of the work of the biophysicist and biochemist are of great
importance to the biologist, this work is not, strictly speaking, of
nature, and can only be subservient to the real work of the
biologist, which deals
with questions of a different nature, and which uses the results of these other
fields to augment the foundational knowledge on which biology is built.
The biologist deals with the biotic aspect of the organism, and is not content to limit himself to asking mathematical, chemical or physical questions about the organism, important as those questions may be. Truly biologic questions deal with numbers, distance, and time, but in addition must concern themselves with the dynamic organization of the organism, and delve into its complexity, its organization in the full context of life, as that particular organism lives it. If we limit ourselves to asking physical and chemical questions we will limit our knowledge to physical and chemical knowledge. But as biologists we must ask other questions which cannot he answered by chemistry or physics, and which will open up vistas of biotic knowledge. When we deal with problems of inheritance, dominance and epistasis may he explained on a biochemical basis, but can never he fully expressed in terms of chemistry, because they are more than just chemical reactions. The place of an alga in the food chain, too, cannot be expressed just in terms of chemistry even though as a food it undergoes a number of chemical reactions. Tropisms of plants are known to be based on chemical and physical principles, as, e.g., the growth of roots toward their source of water, but all chemical and physical principles put together fall far short of explaining the full situation in which this tropism occurs. Or, again, the relation of the structure and function of, e.g., a mitochondrion is a matter of concern strictly for the biologist. And the parent-to offspring relationship which exists between a plant and its seedling, or between a child and its biologic father, is forever beyond the reach of chemistry and physics, even though these fields may contribute much toward an understanding of how this relationship came about. The complexity of metabolic pathways, their purpose and interrelationships among each other, placed in the wider context of cell organization, is still another situation which is accessible only to biology. These are only a few representative examples demonstrating the fact that a number of questions can and must he asked by the biologist beyond those dealing with physical, chemical and mathematical aspects of an organism in order for the biologist to he truly active as a biologist. And it is in his asking these questions that he begins to uncover the biotic aspect of the organisms in all its complexity and beauty. In finding out more about the biotic aspect he will then also find out more about what the living organism (or "life") is all about.
Now the task remains to elucidate the relationship of the biotic to the other aspects of an organism. When
we see a living organism we recognize its biotic aspect in our naive experience, and immediately we want, as scientists, to ask many questions about this organism. But as soon as we subject the organism to analysis, we find that inevitably we become involved in questions which are also of a physical, spatial or numeric nature. The fact is inescapable that the biotic aspect is inseparably intertwined with the other aspects, and, in fact, presupposes the other aspects, and is based on them. Yet it is the biotic which you recognize, and it is the biotic only which sets the organism apart as a living being. But it is not simply a super additurn which can be separated from the rest, analyzed all by itself, and then restored to the "lower" part. It is therefore easy to see why in many instances the failure to distinguish the biotic aspect from the other aspects results in a number of problems which are of such a nature that they cannot be solved unless the questions asked are replaced with truly pertinent ones.
In conclusion I would like to demonstrate with an example some of the implications of the above. We may be able to find a calcium carbonate molecule outside as part of the soil. This molecule is subject to the elements of nature, and may some day, after a heavy rain, be dissolved in water, and subsequently, after the water evaporates, recrystallize and again be just a part of the soil, At a later date a cabbage seed may fall in the soil, sprout, and grow into a cabbage. Again the rains come, and the molecule of calcium carbonate is dissolved in the water. But this time it is absorbed by the roots of the cabbage, and the molecule becomes part of the mineral content of the cabbage, or it may be incorporated into an organelle of a cell, and become an integral part of the plant. If now a rabbit comes along and eats the cabbage, the same calcium carbonate molecule enters the digestive system of the rabbit and hence is absorbed into the blood stream, and may eventually end up as part of the rabbit's hone. The molecule, in a physical sense, has not changed at all, for structurally it is the same. But the status of the molecule when it is part of the cabbage's organelle or the rabbit's bone has radically changed, because it has become an integral part of an organism, where it plays a role in the total life situation of the plant or animal. As long as it participates in the complex organizational set-up of the organism, as part of the skeletal system for locomotion, or as part of the intricate mass of metabolic pathways within any cell, the calcium carbonate molecule has a status different from when it is merely a part of the soil.
It is therefore not the structure of the molecule, nor the biochemical reactions in which it is capable of participating, which gives the calcium carbonate molecule its special status, but its being a part of a living organism. And in a similar way we can say that a living organism is an organism, not because of its chemical constituents or reactions, or of its physical properties, but because of its unique constitution and organization, which is characteristic only of living organisms, which is recognizable by an individual in his native experience, and which is distinct from, and yet inseparably intertwined with, the other aspects of the organism.