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Biology as Engineering: The Way Forward

Evolution News
Photo credit: Ryan Louderback via Unsplash.

By all accounts, everyone enjoyed the Conference on Engineering in Living Systems (CELS 2021) earlier this month. Paul Nelson said, “I would put this meeting up against any of the professional society annual meetings that I attend.” Michael Behe called it a “wonderful experience.” And Brian Miller considered it potentially historic, “a turning point for the ID movement but also a turning point for the biological sciences.” See previous comments from Evolution News writers here, here, here, and here

Dr. Miller noted that some evolutionary biologists, such as systems biologists, have lately been employing engineering language to account for the complexity of life. 

The language of engineering — the tools of engineering — have become mainstream among biologists. To make advances in their field, they have had to use design-based thinking. For philosophical reasons they deny that fact, but it seems there’s only so long they can live with the cognitive dissonance before they have to accept the truth that life looks designed because it is designed.

A turning point implies a journey forward. CELS is admittedly just a beginning. As organizer Steve Laufmann noted, “This is the starting point for new and fascinating (and much-needed) work.”

Points Needing Elaboration

Ways to move forward can be glimpsed in some of the detailed questions that were presented and discussed at the conference. For instance, in what ways are engineering and biology similar? In what ways are they different? How does the engineering approach to design differ from historical design arguments? Does it qualify as a scientific revolution?

Another point is whether the functions of an organism can be delineated by a list of design requirements. Engineers live and breathe design requirements. Before building a system, they have to know what the system is expected to do. Darwinians observe organisms and often assume that nature somehow “selected” traits that enable the function that is observed. How many times have readers heard just-so stories that birds and bats “evolved wings” that allow them to fly? An engineer, by contrast, would look at a flying organism and approach it as a successful implementation of design requirements. In order to fly, this animal would need wings, power, reduced weight, and dozens of other specialized properties. The question becomes: what are the minimum requirements to enable powered flight? Once the list is enumerated, philosophers of biology could ask what mechanisms would be available to meet those requirements. Michael Behe remarked, “What one realizes is that it’s a whole lot more difficult than even I had thought.”

Competing Design Goals

Another question involves trade-offs. In human engineering, design goals sometimes compete with one another. An engineer often must make sacrifices to achieve the optimal combination of traits. As ID thinkers have noted, a well-designed laptop needs power but also light weight, a readable screen but compact size, ergonomic design but also speed. It cannot have the best possible memory, CPU, battery and screen simultaneously without sacrificing weight and ease of use. The optimal design for a laptop successfully balances these design goals, hitting the “sweet spot” that will meet the needs of the customer. When an evolutionary biologist complains about “poor design” in some organism, is he or she failing to consider the trade-offs involved?

Limits to variation is another significant point to clarify. Heretofore, ID advocates have represented diverse opinions on how much an organism can vary, with some accepting universal common descent while others express skepticism that species can vary beyond the genus or family level. An engineering perspective can shed light on this question by analogy: how many changes can be made to a bridge or aircraft before it fails? What kinds of changes are permissible, such as spandrels or decorations, and what variations cause failure? Large changes are clearly observed in biology. A giraffe can grow from a zygote to an 18-foot-tall adult while keeping all its organs and systems coordinated. From the fossil record, we know that groups of organisms have varied widely in size, shape, color, and other traits. Are there limits that organisms cannot cross without catastrophic failure?

Related to that question is the issue of adaptation. Darwin prided himself on the ability of his theory to explain the close fit of organisms to their environments. But it is far from clear that his “mechanism” of natural selection operating on chance variation was up to the task. Adaptation is observed in biology, but what is driving it? Engineers can potentially clear up much of the muddle regarding “selection,” which has always implied some mystical “blind watchmaker” or “tinkerer” that uses the “whatever happens to work” method of design. Darwinians often resort to phrases such as “selection pressure” that portray evolution as a mysterious force that drives organisms to adapt. Describing life in engineering terms is bound to bring much-needed precision of language to biology.

New Terminology

21st-century biology will have use of powerful concepts imported from engineering. Many of these have been growing in use among systems biologists and those who consider neo-Darwinism inadequate. They include, but are not limited to:

  • Functional requirements
  • Specifications
  • Signal processing
  • Networks
  • Reverse engineering
  • Computation
  • Information processing
  • Control systems
  • Top-Down modeling
  • Optimization and trade-offs
  • Modularity
  • Robustness and Anti-fragility
  • Dynamic balance

Elaboration of these concepts, furthermore, can be pursued at all levels, from molecular design, the cell, the organ, the system, the individual, all the way to entire populations and ecosystems.

Lively Discussions

Another aspect of adaptation concerns internal vs. external mechanisms — a factor that generated lively discussion at CELS. In Darwinism, the environment is the primary driver of change. The problem with that is that it turns the environment into a magical “agent” capable of forcing organisms to develop complex systems, such as lungs or egg-laying, when the habitat changes. The environment, though, is blind and careless about the organism’s functional requirements. Instead of locating the mechanism of change in the external environment, engineering-acquainted biologists can consider mechanisms internal to the organism as the primary drivers for adaptation. 

By analogy, a good robot designer can use foresight to prefabricate capabilities for solving problems the machine may be expected to encounter. NASA’s engineers designed the Mars rovers, for example, to sense the edge of a cliff and stop. Since design for robustness is a bread-and-butter concern of engineers, the search for internal mechanisms for adaptation in living organisms makes for a good project for engineering-aware biologists. Some eye-opening examples were presented at the conference. They can involve genes, regulatory elements, horizontal gene transfer — or mechanisms that remain unknown because evolutionary biologists have not been looking for them.

Darwinian Baggage

One final question concerns Darwinian baggage. Does an engineering approach to biology need neo-Darwinism at all? Or might some of the insights from 160 years of evolutionary biology continue to be useful after the “turning point” mentioned by Brian Miller? Is the angle of turn, so to speak, oblique or acute? Participants at CELS were divided on this question. Paul Nelson urged the group to be careful not to alienate evolutionary biologists, but rather invite them to consider the insights that engineering can provide. 

Nelson pointed out one great advantage of the ID and engineering approach: freedom of inquiry. With a word picture, he reacted to CELS:

I’ve used the metaphor of two sets of toys. Imagine a five-year-old going into a room and in one corner there’s a nice set of toys, and in the opposite corner of the room there’s a different set. At this meeting, we can use all the toys: both the best of evolutionary theory, and what it’s learned over the century and a half, and the best of design insights and reasoning.

Whatever spectrum of opinion remains viable in the future, it seems certain that a change of direction is coming.