Nutrition
Let me review briefly what I said in the previous part about the characteristics of inanimate bodies as inanimate, so that we can compare the properties that living bodies have in addition to them, and thus be able to see what it is that makes them distinctive.
You will recall that, first of all, an inanimate body is in equilibrium only in its ground state, which is the state of minimum total energy (and by implication minimum energy in the unifying activity) for that form of body (or unifying energy). Secondly, the inanimate body's instability is determined by the amount of the excess energy it has; and this determines, of course, the purpose or ending equilibrium of the change. Thirdly, an inanimate body is always doing all the acts it can do in the condition it is in, whether this condition is instability or equilibrium. And fourthly, inanimate bodies cannot avoid absorbing energy that they are capable of absorbing, which puts them into instability; they have no means of protection from the energy falling on them.
Now then, we can state a general hypothesis, which "stands to reason," but which should be capable of being verified by our investigation:
HYPOTHESIS: A being is a higher kind of being than some other one if it can do all that that other being can do and can do acts that the other being cannot do.
This, as I say, stands to reason, because properties reveal the nature. If A can do all that B can do, then this implies that the structures (the unifying energies) of the two beings are equal; but if B in addition to this can do acts that A cannot, then B's organization gives it "greater power" than A, and hence its essence is greater or less limited.
The reason I say that this is capable of being verified, even though we can't actually observe the unifying energy from the outside (as I mentioned in the preceding part), is that we are going to see that in the case of living bodies, the reason they can do the acts they can do has to be that their unifying activity either is less "dominated" by its quantity, or that it is essentially not quantified at all. So they are not greater because they can do more, really, but what they do indicates that in fact they are less limited than inanimate bodies.
I hasten to add that this does not necessarily mean that they are better than inanimate bodies. "Good" and "bad," and of course "better" and "worse," are terms that depend on your a priori expectations of something, as I stressed in Chapter 5 of Section 2 the preceding part 2.2.5. A good rock is a good rock if it does what you expect a rock to do; a plant (a higher kind of being, as we will see) can be a bad plant if it grows in your garden where you don't want it and resists any attempt to kill it. This hardiness is, however, the plant's vigor, its success as a living body--as you can see from the fact that you only wish the flowers you were cultivating were that aggressively healthy. But the "goodness" of this tenacious hold on life depends on whether you want the plant to live or not.
"Lesser" and "greater" (and "higher" and "lower") are factual judgments, which depend on scales that you can set up that deal with things in terms of more and less; and judgments like this are objective and imply no evaluation. Scales for these depart from a "zero," which is arbitrarily set and a given quantity can be positive or negative, depending on where you put the zero. "Worse" and "better," on the other hand, are evaluative judgments and imply falling short of or fitting some ideal; and so they are subjective and only deal with the facts insofar as the facts match the subjectively created ideal. With "worse" and "better" the standard or point of departure is not a zero, but a "best," the ideal itself; and it is only if your standards are not very high that things can be better than the ideal; in general, they will fall short of it.
With that out of the way, let us look at the type of activity I call "nutrition." This includes things like respiration as well as eating and drinking, and it takes different forms depending on the type of living body you are talking about. Hence, we should give it a definition:
Nutrition is the act of taking into the body energy and other bodies, breaking up those other bodies, and integrating some of their energy and parts into the body.
Plants perform this act by photosynthesis and osmosis, animals generally by breathing and eating. Fortunately, we do not have to go into detail in it, because it is a very complex kind of act, involving some really ingenious chemistry by which energy can be unlocked from the nutrients with as little expenditure of energy and as little loss of energy as possible; and in complex organisms it can even involve other organisms living symbiotically with the host and making the completion of the act possible-- such as the bacteria in our intestines which help us digest our food.
The reason we don't have to consider the actual mechanism of the act in detail, while biologists do, has to do with the difference between the focus (what is traditionally called the "formal object") of the two sciences. Biology is precisely interested in what the living being is doing as alive, and in how it maintains itself as living, while philosophy is interested in what the property in question reveals about the nature of the body in question.
Obviously, both investigations overlap. Biologists are not solely interested in the mechanisms by which living bodies stay alive and keep the species stable; they are also curious about what these acts say about the living body. But the focus of the science (in modern times, at least) has been on the former issue; and the result is that when biologists make statements about what these acts mean with respect to life, they are apt to leave their careful, methodical procedures and make statements that are plausible but really unsubstantiated, and in fact often false. They are being philosophers, and--not surprisingly--many of them are not very good ones.
Philosophers, of course, have the reputation of not letting little details like facts bother them; and when they pay no attention to what biologists are doing, they also make some pretty wild statements. For instance, Henri Bergson seized upon the data of evolution, and developed his whole view of the élan vital which was driving living things onward and ever onward toward greater complexity and higher forms of life, though the biological data indicate that the actual tendency of evolution is conservative, resisting change and attempting to maintain the species "as is" as much as possible in the face of a changing environment--not to mention the fact that the changes in species don't come about from a drive from within, but from interference with the genes from radiation and so on attacking the organism.
This view of Bergson's is actually rather widely held by biologists themselves, in spite of the fact that it goes directly counter to what the biological evidence is saying. It just goes to show that you have to be very careful in interpreting data not to let the interpretation that appeals to you get in the way of seeing where the facts lead.
Neither science is really independent of the other; and biology is particularly necessary for philosophers as a verification of their various theories of the meaning of life. But this does not mean that philosophers have to know the details of what biologists are discovering, except insofar as these details affect what the act is actually doing.
For instance, the difference between photosynthesis and respiration as acquiring energy is not really significant philosophically; what is important is that energy is taken in and used both to manufacture the parts and create or maintain the level of energy implied in the body in question. The same goes for osmosis as opposed to digestion in taking inside the body the foreign bodies that it needs for parts and energy.
The first thing to note about this property (of nutrition) is that it is not simply a reaction to outside energy, but actively seeks that energy. This is true even in plants. It is not just that their leaves are reacting to the sunlight by performing photosynthesis; the leaves on the plant are so arranged as to take maximum advantage of the sunlight. This can be seen from the fact that plants grow in just such a way to expose as much of their leaf surface as possible to the sunlight, as anyone who has a house plant can verify as he sees how it leans toward the window.
True, this growth toward the light is by means of a mechanism by which the cells on the dark side of the plant reproduce faster than those on the light side, so that the effect of this is a leaning toward the light. But we saw in the preceding part that any property of a body is going to have a mechanism to do the job; but it is the body as a whole which is acting through the mechanism, and the body is not just a bunch of mechanisms that got stuck together.
I am stressing this because biologists are apt to say, once having discovered how the plant leans toward the light, "See? It wasn't any 'desire' to be in the light at all; it's just that cells grow faster in the dark, so that the dark side of the stem grows longer. That's all it is." That's what it is; but that's not all it is. The mechanism has a function for the body as a whole, and what it does is make the body as a whole able to exist even in an environment that will destroy it unless it gets closer to the light.
The same is true of osmosis. It involves a semi-permeable membrane, which takes in fluids (with their nutrient chemicals) depending on the difference in fluid pressure outside and inside the root of the plant. This "happens" to prevent the plant from being overwhelmed with nutrients it can't use, and yet allows it to absorb nutrients when it needs them--and of course it can be thwarted, as plant owners also know when they overwater their plants and see them decay from too much kindness.
What I am getting at is that if we pay attention to the mechanism itself and how it works, we will see that it works mechanically, and we are apt to miss what it is doing for the organism; the mechanistic biologist's attitude is that it's the mechanism that is primary, and it happens that this leads to the survival of the organism, and so (not surprisingly) the organisms with these mechanisms survived and the other ones didn't.
But this ignores what we saw of bodies in the preceding part: that the parts are secondary to the whole, and that the act of the part is the act of the whole in and through the part. The mechanistic view of what an organism is doing is another version of the material fallacy we spoke of in Chapter 2 of Section 2 of the preceding part. 2.2.2 There, we noted that the molecule behaves as a whole entirely differently from its constituent atoms, even though you might be able to tell from an electron micrograph where the atoms' nuclei are in it; and so what is important or significant is more what the unification is than what is unified.
This is even truer here. The mechanistic view ignores the fact that the mechanism itself was built by the organism as a whole, that it gets repaired by the organism as a whole (by means of other mechanisms, of course), that when it malfunctions, it is often sloughed off by the organism as a whole if it is a danger to the whole, and so on. To say that all these things "just happen" to have occurred, and in each of the different kinds of living organisms, in spite of the differences in mechanisms that perform for the organisms essentially the same function, and that all of them "just happen" to cooperate so that one organism's waste is another's food and so on--this is to stretch coincidence to the point of insanity.
Faced, then, with the obvious fact that salt is not the same as sodium + chlorine and the fact that the mechanisms--all of the mechanisms--of a living body function for the maintenance of the body as a whole (which is just what you would expect if it is a body), and faced with the fact that you can't believe of yourself as a body that you are a bunch of parts that "just happen" to be connected together and are not a unit, then it seems to me that the mechanistic view of living bodies is a rather ill-thought-out view that has nothing rational to recommend it. People who hold it had better never play at craps with people they don't know, or they'll be fascinated by how often certain combinations "just happen" to turn up when their opponent has the dice.
But then what is nutrition doing for the body as a whole, and what does this say about what the body is? Let us look at the mature organism as our model; growth only adds a complication.
Nutrition, first of all, is an active absorption of energy, which implies two things: First, that the organism is losing energy, implying that it is unstable, and tending toward its ground state; but secondly, that the organism regains the energy it loses. In the second place, nutrition is an absorption of parts, implying that the organism's parts (in its mature state) are themselves unstable and wearing out, and it is actively rebuilding the worn-out parts.
This second characteristic of nutrition is not perfect, especially as the organism becomes more complex. Nerves, for example, apparently cannot be regenerated (though they are built, of course, by the organism in the first place); and so when a nerve wears out, that is the end of it and its function. But there is an enormous redundancy in the nervous system, so that the loss of great numbers of nerves as time goes on is barely felt.
This lack of ability to build some parts in more complex organisms might be due to the fact that the rebuilding itself has to be done by means of a mechanism; and it is quite probable that as the organism becomes more complicated, the mechanisms necessary to rebuild all the parts would take up so much of the organism's (necessarily finite) energy and parts that it would not have enough left over to make efficient use of the parts it has. Hence, while a complex living body is in its early, purely vegetative stages, it builds far more of these parts than it is ever going to use in a normal lifetime, and then does away with the mechanism that builds the parts, relying on redundancy from then on when the nerves and so on wear out.
But to return to what nutrition is doing, the interesting thing about it is that it implies both that the organism is unstable, and that it keeps itself in this unstable condition. The organism--plant or animal--absorbs the energy it "needs" to keep acting as itself, and in general it absorbs neither "too much" nor "too little." That is, you breathe faster when you are exercising and losing energy quickly; you breathe slower when you are calm and not losing much energy; and hibernating animals hardly breathe at all. And you will note that if you deliberately breathe too much, or hyperventilate, you get dizzy and faint--at which point you breathe less. It is also true that organisms in their natural condition eat the amount that keeps them "in shape," and that it is basically humans and their pets that eat so much that they are less capable of acting.
What all of this indicates is that there is a definite energy level which is maintained, but that this energy level is above the ground state. When there is more energy than this "optimum," which differs for each organism, even within a given species (we all know people who can eat and eat and not gain weight), the organism uses up energy it has stored and does not replenish it; when there is less, it seeks out energy.
Let us call this energy level "biological equilibrium."
Biological equilibrium is an energy level above that of ground-state equilibrium, which the living body maintains by nutrition.
It is the maintenance of this super-high-energy state that shows the fallacy of the mechanistic view of the living body. This biological equilibrium is precisely unstable from the point of view of the physics and chemistry of the body, as can be seen from the fact that all of the living acts of the body use up energy and dissipate it to the environment. To take but one example, the fact that we maintain our bodies at a more or less constant temperature of 98.6 degrees Fahrenheit means that our bodies are kept hotter than the surroundings, which in turn means, by the Second Law of Thermodynamics, that we are constantly giving off heat into the surroundings and growing cooler. Hence, as far as the physics of the body is concerned, our temperature is unstable; we would be like the cold-blooded animals, and have a body temperature the same as our surroundings, if we were to be in thermal equilibrium.
Yet this unstable temperature is clearly an equilibrium temperature for the organism; because when we exercise and get hotter, we sweat, and the evaporation cools the body back down to this temperature; and when we get cold, we shiver, and the exercise heats the body back up to this temperature. This temperature is clearly the purpose of both of these processes (in the sense described in the preceding part, as that toward which they are directed); and since it is "aimed at" whenever the body is not at this temperature, then it is obviously in some sense an equilibrium.
But biological equilibrium is different from the equilibrium in inanimate bodies, because when the body gets there it doesn't just stay there. It can't, apparently because the body is a body, and as such has as its "bodily" equilibrium its minimum amount of energy; hence, as a body, the living body is unstable at its biological equilibrium energy-level, while as living, it is stable at that amount of energy.
If living bodies were a bunch of mechanisms that "just happened" to be connected together, then where did this new equilibrium come from? Any mechanism tends of itself in no direction but toward its ground state; and this is as true of systems of many mechanisms as it is of a single mechanism. Your car does not start itself up and go looking for the gas pump, even when the fuel in the tank is low.(1) Your computer doesn't have an "optimum" energy-level it tries to keep; when its batteries run down, they run down. It may have a program that warns you that this is happening so that you can recharge them; but it doesn't care; all it's trying to do, actually, is run down.
So we can immediately draw this rather startling conclusion:
Conclusion 1: From the point of view of the physics and chemistry of the body, a living body maintains itself in an unnatural condition.
That is, the nature of the living body as living is to be at this high energy level of biological equilibrium--which is unnatural from the point of view of that same body's physics and chemistry. There is, then, in the living body a tension between its nature as alive and its nature as bodily, indicated by the pull toward its different equilibrium energy-levels at the same time.
"From the moment we are born, we are dying," some say, as if the purpose of life was death. And it is, based on the physics and chemistry of the living body. But from the moment we are conceived, we are fighting off this tendency, and striving to either reach or maintain that other energy-level, where we can perform all of our living acts; and so the purpose of the living body as living is not death at all: it is biological equilibrium. Organisms die because as bodies they are unstable and they cannot "close off" their energy and keep it from being lost out of the body, hard as they try to do so by the efficiency by which they acquire and keep energy.(2)
But since the living body, like all bodies, is a set of parts that are interacting with each other in a certain way, and since the parts are just mechanisms, we can draw the following conclusion:
Conclusion 2: What gives the living body its biological equilibrium is the unifying energy of the body.
We stated in the preceding part that instability is basically the discrepancy between the form of the unifying energy and its quantity; but we didn't make much of this, and spoke most often in terms of the discrepancy between the total energy of the body and what the equilibrium total energy is.
But here it seems that we have to "blame" precisely the unifying energy for the peculiar kind of energy-discrepancies that are in the living body as living, at least. The parts, as physical and chemical, can't account for the body's being unstable when it is below biological equilibrium, since it is only when they are actually organized into a living organism that they seek this biological equilibrium.
That is, an animal that is suffocated still has all of the parts of the body, and they are still, by and large, all functional. But it is a corpse, not a living body; and the sign that it is a corpse is, of course, that it is now decaying, or losing energy and going down toward its ground state of minimum energy. Hence, the biological equilibrium is not to be found in any part or even in all the parts taken together; it comes from the way the parts are interacting. When they are interacting as living, then it seeks and maintains a super-high equilibrium; when they are not, it disintegrates.
We must not, however, leap to a conclusion and say that this unifying energy is actually some kind of spirit that "gets into" the body somehow and directs it the way a pilot directs a ship. If it is a spirit, why is this biological equilibrium a definite amount of energy, different for each organism? A spirit has no amount to its activity, so why would it determine some definite energy-level for the body it is "inhabiting"--not to mention why would it bother to get into a tulip or a cockroach to live there in the first place?
Secondly, if a living body is alive because some kind of spirit has got into it, what do you do with all the organisms that reproduce by dividing? Most single-celled organisms reproduce in this way; and even with plants and some animals (like starfish), if you cut off a part, the part will grow into a whole organism and the organism will grow a new part to replace the one cut off. Does the spirit get divided?
If it does, then in these cases, the body it produces is an identical twin of the original, with the same energy level as its biological equilibrium. But in the case of sexual reproduction, the biological equilibrium is different from that of either parent. Did the two spirits mix? How could they if they are the same form of activity without any quantity at all? But then where did this new spirit come from?
No, it seems that if you want to say that because the biological equilibrium is above that of the ground state, therefore what is responsible for it is a spirit, you get into predictions that don't fit the facts of what organisms are doing. Hence, the most reasonable hypothesis is that what makes the body live is the unifying energy, which is in itself the interaction of the parts of the body.
With that said, however, it must be stressed that this interaction is peculiar, because in some sense it goes beyond the parts that are interacting. That is, even if it "comes from them" in some sense, it is still beyond them, because they are essentially just chemicals, and their tendency is not to exist together at this high energy level, but to go to their ground state.
You can verify this from the fact that a heart taken out of a body can be maintained as a heart; you can keep it alive and pumping. But it does not have, like the body it came from, any active tendency to keep itself alive. As soon as you turn off the whatever is forcing it into his high-energy state, it begins to decay. And the same is true of any other part of a body. You can even keep the parts of a corpse alive artificially, so that the corpse seems to be a person in a coma; but it is just that each part is being forced into the high-energy state it would be in if it were a part of the living body, and all the parts are being forced to act as they would be if they were being integrated by the body's unifying energy. But the unifying energy isn't in fact integrating them, and as soon as the "life-support systems" in this case are turned off, the corpse shows what it really is: an inanimate body.
This is not to say that life-support systems--even many of them--can't be actually keeping a body alive, as the famous case of Karen Ann Quinlan in the 1980s demonstrates. When her body was taken off the life-support systems, it stayed alive for years, indicating that the parts were being held at their super-high energy level; but that the mechanisms by which the body as a whole could act in a normal human way (e.g. the brain) were so defective that the body could perform only its vegetative acts in this condition.
There is one further conclusion we can draw about biological equilibrium and nutrition:
Conclusion 3: Life is not really a constant process; once maturity is reached, its tendency is to stay the same (equilibrium).
It is easy to be misled dealing with life and process, because living bodies are constantly in process, since there is this tension between their equilibrium as living and their equilibrium as a body. Hence, maintaining biological equilibrium will involve processes in living bodies, because the body, as physically unstable, is always losing energy, which must be replaced; and, of course, a change in energy level of the body is a process, as we saw in Chapter 5 of Section 3 ofthe preceding part 2.3.5.
But when the organism is in its mature state (which involves most of its life in most organisms), the processes are always headed back to the equilibrium that was lost, whether the energy-level is above this biological equilibrium or below it; hence, while each of these is a process, there isn't actually any process in the living body itself, either as living or as a body. There is a tendency toward the ground-state equilibrium; but this is constantly thwarted by the living acts of nutrition and self-preservation generally; and so the saying I quoted earlier that "from our earliest moment we are dying" is not really true. There is no gradual progression toward death; there is, first of all, a gradual progress toward the mature state, and from then on a "hovering around" that state until the physical nature of the body finally becomes too much for the body as living, and then the dying process can be said to begin. But as long as the living nature of the body is "winning," then there is no real process toward death.
This has some rather significant implications. We have been told from the time we were young that "life is constant growth," and that we should be always headed beyond ourselves or we aren't really being true to ourselves as alive. This is simply false.
Actually, it's one of those hortatory falsehoods that wouldn't need to be uttered if it were true. If life were constant growth, and constant reaching out toward greater and greater heights of being, then obviously the tendency would be there inside us, and we wouldn't need urging onward, any more than a five-year-old has to be urged to get bigger; he can't help it.
No, the reason people tell us that life is growth is that our tendency is to resist changing, even when it is "improving ourselves." Once we've reached maturity, the tendency is to "settle down," and security (read: "equilibrium") is the overriding concern. We may develop to "keep up with the field"; but this is like what the Red Queen said to Alice, "Here you have to run as hard as you can just to stay in the same place."
So if you are stuck in complacent mediocrity, then you are simply doing what is natural, and you don't have to feel guilty about it. True, as human beings, we can set goals for ourselves at any time--which is another way of saying that the actual energy-level (with its attendant properties) that is to be our biological equilibrium is up to our choice and isn't built into our genes (except in some respects like physical height and so on). But just because you can put yourself into a new instability and head toward a new goal doesn't mean either (a) that you should, because what is the sense of being free to set goals if you can't stop setting them? Nor does it mean (b) that it's unnatural for you to stop at some goal you feel "comfortable with," even if you're not living up to your full potential. Being able to set goals for yourself means not having to live up to your full potential if you don't want to. What else could it mean, if you think about it? If it meant anything else, then the only choice you would have would be living up to your full potential (which you discover, not choose), or being morally evil, because you would be deliberately contradicting your nature. In other words, not doing your absolute best would be to do wrong.
But we will see more of this later, when we talk of human life. I want to mention it now, however, because it is a tendency of all living bodies to reach a "plateau" and then stop, and it needs stressing as much as possible, because there is such a strong urge in people to make sure that this doesn't happen with others that they are apt to assign this natural tendency to "the fact that our nature is fallen" (as indeed it is, but not for this reason) rather than that it is the nature itself.
I might remark that it sounds as if "life" is this biological equilibrium. It is, in fact; but let us look at the other distinctive properties of living bodies before we get around to defining it formally.
But before doing so, let me note something that probably belongs here in a discussion of nutrition: All organisms rest. Indeed, if my dog is any indication, many organisms spend most of their time resting.
But that is something rather interesting, and what it implies can be put into the following conclusion:
Conclusion 5: A living body is not always doing all that it can do at any given moment.
That is, when a living body is resting, it is capable of doing things that it is not at the moment doing; but there is no occasion for its doing them. My dog, for instance, wakes up as soon as she hears my wife's car coming into the driveway, and she busies herself with "barking her home," wagging her tail, and fawning on her. It is clear that this is a response to some inner necessity on her part, because other cars can pass by and not disturb her at all; so it is by no means a simple action-reaction affair, the way inanimate bodies respond in a given way to energy of a certain type.
But the point to be made here is that the energy to jump up and bark and wag the tail and so on is in her while she is sleeping, and didn't come from the energy of the sound of the car. Hence, there is stored energy which can express itself in (energy-dissipating) activity, but which is not in fact doing so while the dog is resting.
And this makes sense in terms of biological equilibrium. If the biological equilibrium is a super-high energy level, then obviously there is energy "in reserve" held in suspension, as it were, above the ground state; and this energy can be either bottled up inside the organism for times of emergency, or it can be released without any particular external cause accounting for the initiation of the change. The "causes" of beginning to act in living beings are often more "opportunities" or "excuses" than actual causes; the actual causes are inside the organism. This is especially true of humans when they choose to do something.
I mentioned in the discussion on inanimate bodies in the first part that this sort of ability not to do something is not possible in inanimate bodies; because they are either at their ground state and can't do any more (at the moment) than the minimum, or they are unstable with a single purpose: the ground state. Hence, they can't spontaneously keep energy in reserve; it can only be kept there for them by being blocked from escaping, as in batteries.
But living bodies have internally rechargeable batteries, as it were--or at least ones that they charge up by nutrition--and it seems that one of the things that they are doing while resting is recharging the batteries. But sometimes they are just "doing nothing," and not resting precisely to recoup lost energy, but are just resting.
This insight was actually what gave Aristotle his theory of "act" and "potency," as early as his student days with Plato, when he was writing the dialogue Protrepticus. Since he was the son of a physician, it was understandable that he would have noticed this; but in any case, in that dialogue, he discusses in what sense we can call a sleeping animal a "seeing" thing if it isn't in fact seeing. Because, he answers, it "can" see; and this implies an ability in it that doesn't express itself in the activity: a kind of internal activity that stays inside--and thus he began his long and brilliant investigation into energeia, this internal activity which sometimes spills over into what I have been calling the "properties" of a substance or a body. He went on to distinguish many different senses of "being able," which need not detain us here.
But it is worth noting that the concept of nature is quite important in living things, because you can't necessarily tell what their nature is by just looking at them; if they are asleep, then they might look dead. It is obvious that if an organism is actually doing something, then it can do it; but it isn't clear from its not doing a given act whether it's not doing it because it can't or because it just doesn't want to or because it is resting.
But I think one implication of this should be made into a formal conclusion:
Conclusion 6: If an organism is not doing a given act, this does not necessarily say that its nature does not include the ability to do that act.
That is, the organism might simply not be expressing its nature fully. But there is more even than this. There is a sense in which blind people cannot see, and so you might argue that it is not their nature to see. But you must not be over-hasty about this, because blindness can be cured sometimes, and then the one who "couldn't" see turns out to be able to see. Now does this mean the nature changed, or does it mean that some defect in the seeing mechanism was fixed?
I think that we would have to say that if repairs in the mechanism by which an act is performed allow the act to be performed when before it couldn't, that the organism had the nature to perform that act while it couldn't, but couldn't act in accordance with its nature because of the defective part.
In inanimate bodies, perhaps, you could argue that an ion (an atom without some electrons) has a different nature from the atom, because the inanimate body is always doing all that it can do in the condition it is in. But since this is not true of living bodies, I think we have to put the "nature" in the unifying energy rather than in the parts, and say that mere defects in the parts do not necessarily imply an inability in the nature.
But it isn't quite that simple. If the unifying energy built the defective part (e.g. if a person is blind from birth because his eyes were constructed defectively), then there isn't just something wrong with the part, but there's something defective (as far as the species goes) or specially limited about the unifying energy, and so this would be something that could be attributed to the nature.
Thus, people who have congenital handicaps have handicaps, not diseases, and are not "unhealthy," because they can act in accordance with their genetic potential; it is just that their genetic potential is in some respects less than that of most people; their nature is more limited in these respects. But that means that their lives, considering their individual natures, are not unnatural, but just more than ordinarily limited in the respects in which they have a handicap.
Even here, however, it is sometimes possible to correct the handicap, which indicates once again that the unifying energy is rather remarkable. Even if it has a limitation which makes it build a defective part, it is somehow not necessarily bound by this limitation, and can at least sometimes overcome it.
It should be clear by now that once one gets into the area of living beings, things become even more mysterious than inanimate bodies, mysterious as they were.
NextNotes
1. True, you can make mechanisms that do this, such as the one built by Norbert Wiener in the early days of computer technology. It was a turtle that moved around the room, with a photocell that got energy from light; and the computer within it was programed to seek out light and "rest" when it found some, giving the machine the ability to "feed itself," so to speak. The trouble was that if you made the photocell bank large enough to absorb all the energy the machine needed, you made it so heavy that it used up more energy in moving around than it could absorb. In other words, the Second Law of Thermodynamics caught up with it, and it gradually lost energy and stopped moving. What I'm saying is that mechanical systems don't seem to have the ability really to restore lost energy, let alone lost parts.
2. In this connection, it is worth noting (as we will do later when talking about the human body as a body organized with a spiritual--and therefore immortal--act) that it is at least conceivable that a body might be able to lock in its energy once it reached its complete mature state, and so be alive forever even as a body. As we will see, the higher you go in the scale of life, the more the body has control over its energy level; and who is to say that such a locking in of energy is in principle impossible? It would mean that the living body could not change any more, of course; but that would not mean (any more than it does for inanimate bodies in equilibrium) that it would be inactive. I am not trying to say that this happens, but only to say that there is nothing in principle impossible in its happening.