Excerpt from my book Machine Nature
An eagle flaps its wings; a Boeing 747 doesn’t. A dolphin wiggles its body and jiggles its fins — a submarine just has a motor in the back. A dog walks on legs; a Mercedes-Benz rolls on wheels. A rose runs on water and light; a flashlight runs on batteries. A tiger develops in a womb from a single cell to a magnificent multicellular beast — a toy tiger is constructed full blown in a factory. A piano player goes through years of intensive training, learning to hone her talent; a piano learns nothing. Homo sapiens have evolved by means of natural selection; watches are designed by watchmakers.
Engineers and Nature have usually taken distinct routes in their creation of complex objects, differing both in the final artifacts produced as well as in the design process itself. And the recent movement that seeks inspiration in Nature has come up not only with novel objects but also with entirely new ways of designing objects. Thus, current-day robots may possess legs, fins, or wings; electronic circuits may develop in a manner akin to that of multicellular living beings; watches can heal themselves; computers can learn to play a mean game of backgammon; and bridges can be evolved.
Having visited several lands in the Terra Nova of computing, and having acquired along the way many new colorful approaches, we shall now use these colors in the remainder of the book to paint the big picture. In this chapter I’d like to take a closer look at the main differences between human’s work and that of Nature, specifically focusing on how these relate to our current engineering efforts. When does it pay to be biological, and when is it better to use the traditional, by-ole-logic way? As a concrete example I’ll consider two different kinds of flying machines: birds and airplanes. When engineers set about to design an airplane, they proceed in what is known as a top-down approach: They start with the general issues and questions (the top) and go all the way down to the nitty-gritty. At the top there is the decision — usually made by senior management — to build a new airplane. Next comes the requirements analysis phase, which basically answers the question: What should this new machine be able to do? It might be required, among others, to carry up to 600 passengers, to take off and land on short runways, and to handle severe weather. Having defined the problem, it is time for the engineers to enter in force, their job being to find a solution; now that we know what we want, it’s time to see how we go about building it.
The design process continues in a top-down fashion, breaking the big problem into smaller and smaller subproblems; one doesn’t jump immediately to the nuts-and-bolts level. This breaking-down process might be done by identifying key parts — such as the cockpit, the fuselage, the engines, and the wings — and assigning their design to different teams (which obviously must cooperate among themselves. After all, there is but a single final object being built: the airplane). Each such key design problem is further divided into smaller subproblems; the wings team, for example, will be considering flaps, spoilers, ailerons, and other such beasties. The design process is by no means simply a forward march; often one must go back to the drawing board since the part in question doesn’t function as it should. This back-and-forth process ends up with a design specification — a complete plan of the airplane (such a complex object might require years of design work). Now it’s time to fabricate the machine, a task which in itself may be quite elaborate for such an artifact. It might, in fact, require a separate design process since in all likelihood new fabrication techniques for the new airplane will have to be developed.
Engineering designers thus start out with a clear top-level goal in mind, then work their way downward toward the most minute details, ultimately coming up with a comprehensive solution. Nature works quite differently. For one thing, Nature has no explicit, a priori goal; Nature does not embark upon a lengthy R & D project whose final objective is the construction of a bird. Nature employs evolution, and evolution is shortsighted: The only goal, the only thing that matters, is immediate survival. Nature, if any designer at all, is a blind one at that. The ability to fly emerges over eons since it confers some advantage to the animals that possess it. Thus, when speaking of evolution’s goal, one can at best describe it as an implicit, short-term one: survival. (In The Blind Watchmaker Richard Dawkins proposed a way by which wings might have evolved. His scenario starts out with wingless animals that leap between tree boughs. Small flaps of skin that help extend the jump or break the fall — by acting as an airfoil — will bestow an immediate survival benefit upon their owner. Little by little, over the course of many generations, the accumulation of small, ever-better modifications to these flaps might end up in full-fledged wings.)
Evolution is further distinguished from engineering in that it is a bottom-up process: Its “products” emerge from the myriad of interactions that take place in the biosphere. There is no top-down process that starts out with a major, far-sighted goal that is then broken down successively into smaller and smaller subgoals, until they become doable. There are just numerous interactions, both among organisms, as well as between them and the elements, out of which emerge all the wonderful devices we see around us (and in us), such as wings, eyes, feet, nervous systems, and rock stars.
Nature’s open-ended, short-sighted, bottom-up style as opposed to engineering’s guided, far-sighted, top-down approach is the crux of the difference between the two. It entails several other distinctions between the engineering enterprise and Nature’s workings.
Engineers usually seek not only to create a widget that works, such as an airplane or a coffee machine, but indeed one that works well; often they evoke terms such as “efficient” and “optimal” to describe their desired product. Nature, on the other hand, cares nothing for these qualities; designs need neither be the best, nor the fastest, nor the most efficient; rather, Nature’s after “just-do-the-trick” solutions, namely, ones that can survive. If an organism has even the slightest advantage over its confreres, then that’s all it takes — it’ll be the winner in the survival race and its genes will pass on to the next generation.
“But how then,” you might be asking yourself, “has Nature come up with all those marvelous designs we see out there — such things as seeing gadgets, delicate manipulators, and thinking machines, which are still way beyond our current engineering capabilities?” First off, let’s not forget that Nature has had a bit of a head start — 3.5 billion years to be precise. This figure should not be brushed aside lightly: It is a huge amount of time, practically impossible for us to grasp. As noted by Charles Darwin in the Origin of Species: “The mind cannot possibly grasp the full meaning of the term of a hundred million years; it cannot add up and perceive the full effects of many slight variations, accumulated during an almost infinite number of generations.” Our inability to grasp such a vast period of time is not so surprising if you think about the environment in which our minds have evolved to function. During most of our evolutionary history, there was no survival value in being able to comprehend the expanse of a million years (nor, for that matter, of a millionth of a second). It is only very recently (no more than a few thousand years) that we have begun dealing with such huge numbers, our minds coming to appreciate time out of mind. While for engineers time is of the essence, for Nature the essence is time.
In coming up with her flying machine, Nature thus spent a little more than the few years engineers spend in designing a Boeing 747. The chirping critters we see today outside the window are superb beasts, yet their beginnings — the ancestral forms that flew the Earth millions and millions of years ago — were probably much less impressive. It’s hard to match our current engineering achievements with those of Nature, but then again, it might also be somewhat unfair. We should probably compare our current-day devices not with modern flora and fauna, but rather with Nature’s first attempts, those that had been in existence so many millions of years ago (and which are now — for the most part — extinct).
Nature not only takes her time but also makes use of a huge amount of resources. Charles Darwin remarked that the evolutionary process goes on “for millions on millions of years; and during each year on millions of individuals of many kinds ...” While an engineer usually tries to cut costs wherever possible, Nature is lavishly wasteful. She works by trial and error, indeed lots of trials and lots of errors. Charles Darwin quoted Milne Edwards as quipping that “nature is prodigal in variety, but niggard in innovation.” There are many more extinct species than surviving ones, or, as Richard Dawkins said: “however many ways there may be of being alive, it is certain that there are vastly more ways of being dead …”
Evolution is basically a forward process: Any new entity must be immediately functional, or else it dies out. As we’ve seen above, engineers can (and often do) go back to the drawing board in order to fix a flawed design. Nature, on the other hand, cannot move backward; there is no drawing board to go back to, no possibility of deciding, “Well, this new wing design isn’t so good, so let’s go back to the old one and try to improve it in another way.” In Nature, no good means no life (as in dead).
Another difference between engineered devices and natural ones has to do with “leftovers.” In human-made systems essentially every single part is accounted for and serves some purpose; if not, then it is removed without further ado. Nature, on the other hand, tends to accumulate junk, her motto being: “If it’s not harmful then it’s none of my business.” Why waste effort on removing innocuous parts? Modern creatures thus carry vestiges of past epochs that might have served some purpose at one time, but which are totally useless today (our tail bones, for example).
Let’s take stock of what we’ve gleaned so far about the biological versus the by-ole-logic. When engineers design a product, they have a clear goal in mind; they proceed in a top-down manner, seeking to create an artifact that is — as much as possible — the best solution to the problem at hand. Nature, on the other hand, has but a single, short-term goal in mind, survival; she relies on the process of evolution to “design” her products, slowly proceeding in a bottom-up manner, sparing no expense and taking no heed of her extravagant wastefulness. With respect to expenditure one might say that engineers are like Ebenezer Scrooge whereas Nature is like Santa Claus. In a nutshell, Nature designs by evolution while engineers design, well … by design.
Nature has come up not only with ingenious solutions to specific problems — for example, structural designs such as eyes or wings — but indeed has found (and founded) entirely new processes to aid in the emergence of complex organisms. Two of the most important ones are ontogeny (the development of a multicellular organism from a single mother cell) and learning.
Engineers and computing scientists have been turning of late more and more toward Nature, wishing to learn from her ways and means. In building novel artifacts they seek inspiration in a wide range of phenomena, from general processes such as evolution, ontogeny, and learning to more specific natural inventions, such as immune systems, eyes, and ears.
Why are we so enthralled by the biological? After all, the by-ole-logic way is methodical and precise while the biological is so much “mushier.” Think of (or in my case imagine) that sleek, black Porsche 911, comfortably reposing in your garage — a triumph of modern engineering. Since every step of its design and construction involved traditional engineering techniques, we know exactly what it is capable of, and of what it is incapable: how fast it can go, its fuel efficiency, its ability to withstand shocks, its maneuverability along curves, its braking distance, and so on. Contrast this with Nature’s creations, where we are often at loss to answer such questions as: Does it work; if so, why? If not, why not? Does it work well? Does it work well all the time? How far can we push the system? What are its limits? We know how to answer such questions when it comes to a Porsche, whereas a dung beetle presents us with a far more difficult case.
You could argue that a dung beetle is a problem for biologists, whereas we’re interested in a “hard” engineering problem, building Porsches. The problem is that once we move from the by-ole-logic to the biological, using techniques such as those described in this book, we find ourselves on murkier grounds. Consider the robots discussed in Chapter 4, whose brains consist of artificial neural networks that emerge by means of evolution. We find ourselves faced with an engineered machine — the robot — for which we are very hard put to answer all those questions of the previous paragraph (we’ll elaborate on this issue when we talk about scigineering).
It might seem that I come to bury the biological, not to praise it: Why use those mushy, biologically inspired techniques to build Porsches when we have such good, well-known classical methodologies? Well, despite appearances to the contrary, most of our engineering achievements to date are quite simple, at least in comparison to Nature’s. A Porsche is less complicated by far than a dung beetle; in fact, I’d probably be risking very little in claiming that a Porsche is simpler than any one cell of your body! Our engineering techniques have worked wonders in erecting modern civilization, but our appetites keep growing; technology feeds upon itself by creating new niches that bring about new needs and desires for more technology.
The more elaborate our artifacts become, the more difficult it is to find solutions by using only traditional computing and engineering techniques. That’s when we supplement the by-ole-logic with the biological. Notice my use of the term supplement: We’re not rushing to chuck the ole techniques; rather, we want to eat the cake and have it too, combining the by-ole-logic and the biological. There’s no point in being a traditionalist or a Young Turk just for its own sake; the goal is to build better artifacts, whatever the means.
And just what good is the biological to engineers? We’ve been answering this question throughout most of this book; let’s try to summarize some of the benefits we’ve encountered. As I’ve just remarked, technology keeps getting more and more complex, which means that our traditional methodologies run up against a wall much sooner than before; more and more often they are overstretched to their limit — and then some. That’s when we start considering the biological, which often permits us to make do with but a partial design — to be completed through evolution, learning, and other biologically inspired techniques. (Incidentally, even automobile companies have recently started employing techniques such as evolutionary computation and artificial neural networks to design certain parts of their cars.)
When the by-ole-logic is stretched to the limit, it’s worth trying the biological, though one must remember that it is not a panacea. I hope I’ve managed to convey the intricacy of applying these techniques in the preceding chapters. It’s not easy to get a good bridge to evolve or to have a robot learn to walk.
Another salient difference between Nature’s devices and those of human has to do with their robustness. This term means different things in different domains, but it basically boils down to the ability to cope with a wide range of circumstances. Place a cockroach in virtually any imaginable terrain, and it’ll have no problem in walking the Earth; a robot, on the other hand, has a much harder time breaking new ground. (As we saw in Chapter 4, the robotic soccer teams played much better at their home institutes than at the match site, having grown accustomed to the home terrain.) You can suffer a severe blow and still keep on ticking; the same cannot be said of your Porsche. Plants have an uncanny ability to grow toward the light, wherever it may be. A computer recognition system has a much harder time than a human in identifying a previously bearded man who suddenly shows up clean-shaven. From bacteria to brains, there are endless examples of just how robust natural creatures are, a quality that we’d like to instill in our artifacts.
Nature places its creatures in a continual lifetime struggle for survival. Moreover, every living creature today comes from a long line of distinguished ancestors that had one thing in common: They were survivors (at least long enough to engender a dynasty). Small wonder they’ve evolved to be so versatile. After all, robustness is decidedly a boon to survival.
To emphasize just what it means to pass through the evolutionary sieve, let me recount a short tale. The 11 o’clock news announces the founding of a new airline company whose rates are three times cheaper than the cheapest of airlines. How do they manage? Simple: no humans! At Robo Airways every job — onboard personnel, reservation clerks, ground crews — is handled by computers and robots. Would you fly the robotic skies? I’d bet the company would go bankrupt very quickly for one major reason: No one would want to fly without a human pilot aboard. Why is that? After all, any modern-day aircraft has an automatic, onboard pilot that performs much of the drudgery of piloting, and you don’t have to stretch your imagination too far to envisage a fully automated flight system. What’s so special about a human pilot? Well, it’s not so much the piloting abilities as the pilot’s humanness. Obviously, there is a psychological angle that comes into play; a human pilot being much more similar to us than a machine. Let’s dig a little deeper, though.
According to robotics researcher Rodney A. Brooks, an examination of the evolution of life on Earth reveals that most of the time was spent developing basic intelligence. He wrote that: “This suggests that problem solving behavior, language, expert knowledge and application, and reason, are all rather simple once the essence of being and reacting are available. That essence is the ability to move around in a dynamic environment, sensing the surroundings to a degree sufficient to achieve the necessary maintenance of life and reproduction. This part of intelligence is where evolution has concentrated its time — it is much harder.” Playing chess, reading newspapers, and piloting airplanes are very recent skills that piggyback on our versatile brains, which have evolved over millions and millions of years. The title of Brooks’s paper — “Elephants Don’t Play Chess” — nicely captures this idea: While not able to play chess, elephants are nonetheless robust and intelligent, and able to survive and reproduce in a complex, dynamic environment.
When Nature comes up with a new product line, it is immediately subjected to the most grueling series of tests ever invented: evolution. That’s why we can trust the human pilot much more than we can the automatic one: Piloting skills are but a mere add-on to a powerful system whose design has been millions of years in the making. Or, consider another example: Any human can tell the difference between a baby and a doll, our visual system having evolved to be able to keenly distinguish our kin. Yet with Dean, the housemaid robot of Chapter 4, this is far from obvious. How can we be sure it won’t confuse one with the other (with the consequences being anything from comic to disastrous)?
The biological approach to engineering is a powerful sword to be wielded when the old tools fail, or when they yield unsatisfactory solutions. Applying processes such as evolution and learning does have its price, though, since we’ve seen how lavish the biological tends to be. We do have, however, the benefit of very fast artifacts, such as computers; thus, the biological, when applied to engineering, need not necessarily take millions of years (as with natural evolution) or years (as with human learning). Moreover, the biological approach has the potential of yielding more robust solutions, ones that do not fold with the slightest breeze. And let’s not forget that another possible biological approach to engineering is to seek inspiration not in Nature’s grand processes but rather mimic some of her solutions, examples of which are artificial retinas and artificial cochleae.
As I’ve remarked above we need not replace the by-ole-logic with the biological but rather combine the two, thus enjoying the best of all possible worlds. And when opting for the biological, we don’t necessarily have to remain 100 percent faithful to Nature; we can even at times take a bio-illogic path. Let me give just one example, that of Darwinian versus Lamarckian evolution.
The Chevalier de Lamarck was an eighteenth-century intellectual who argued in favor of evolution many years before Darwin. In this he was right. What he got wrong was the mechanism, now known as Lamarckism, or Lamarckian evolution, which is based on two principles: the principle of use and disuse and the inheritance of acquired characteristics. The first principle asserts that those parts of an organism’s body that are used grow larger, and those that are not used tend to wither away. The second principle states that such acquired characteristics are then inherited by future generations. Thus, a bodybuilder bequeaths his developed muscular physique to his children. Or, consider the following story about giraffes: The early ones had rather short necks and so they strained desperately to reach high leaves on trees. These mighty efforts resulted in longer neck muscles and bones, which they passed on to their offspring; each generation of giraffes thus stretched its neck a bit, a head start which it passed on to its offspring.
Lamarckian evolution seems reasonable. In fact, it seems rather enticing: Wouldn’t it be great to have — from day one — all those acquired characteristics of your ancestors? Alas, that’s not how things work, and so the Darwinian theory of evolution has supplanted the Lamarckian theory. The giraffe does not directly pass its long neck — acquired during its lifetime — to its offspring. Darwinism is more roundabout: Some giraffes are genetically predisposed to develop into mature animals with long necks. These will then have an advantage (however slight) over others since they will be able to reach higher leaves. Thus, they will stand a better chance of surviving and leaving offspring, which will in turn inherit the genetic predisposition (which might then be further enhanced through favorable mutations).
While the biological theory of evolution has shifted from Lamarckism to Darwinism, this does not preclude the use of Lamarckian evolution in artificial settings. It can greatly accelerate evolution since a good acquired trait can be immediately incorporated into the genome. There is still a debate as to the use and usefulness of artificial Lamarckian evolution, though my intention here has simply been to show that we need not remain 100% faithful to Nature.
The biological blazes new trails that lead to fascinating lands. But the lesson to take home is that whether by-ole-logic, bio-logic, or bio-illogic, what matters is the end result: By hook or by crook, just get it to work.