Science in Christian Perspective
What Is Life?
AALDERT MENNEGA
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
claim that
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.
The Cell
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
question which
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,
where besides
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
living organisms
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
interest and
importance to the biologist, this work is not, strictly speaking, of
a biological
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.
Biotic Aspect
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.
An Example
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.