Once upon a time, people believed in the soul, a god-given vital force that animated human beings and left the body upon death. Around the 1500s, this theory of vitalism fell from fashion and we started to see beings as more like machines.

Dissections and anatomical drawings showed scientists body parts, and it appeared that sorting out each one would solve our problems. “The metaphor of body as a machine provided a ladder that allowed biology to bring phenomena up from a dark pit of mysterious forces into the light where organic mechanisms can be analyzed,” writes Randolph Nesse of Arizona State University’s Center for Evolution and Medicine.

Since the 20th century, scientists have been busily mapping out ever-smaller and harder-to-reach parts. But the body-as-machine metaphor has gone too far, Nesse argues, because it fails to recognize evolution and organic complexity. He writes:

Machines are products of design, bodies are products of natural selection, and that makes them different in fundamental ways…. Machines have discrete parts with specific functions connected to each other in straightforward ways. Bodies have parts that may have blurry boundaries and many functions and the parts are often connected to each other in ways hard for human minds to fathom. Bodies and machines fail for different reasons.

In other words, we’re more than the sum of our parts. Nesse believes that when we compartmentalize based on an idealized conception, a mere metaphor, we fail to approach the truth of what live beings do: parts interact and are dynamic. This plays out in the way we practice medicine, Nesse says.

For example, “in psychiatry, thinking about the mind as a machine has led to a debacle about diagnosis,” writes the physician. Some mental health experts are dismissive of traditional approaches to diagnosing disorders that aren’t rooted in physical proof, leading to aggravation of people’s symptoms and suffering and, at worst, a total failure to acknowledge and diagnose disease. The reason for this, he says, is that many neuroscientists believe there should be a specific and manifest brain abnormality associated with every disorder; when they can’t find one for a stated malaise, they simply reject the disorder’s existence. Nesse says mental illness isn’t that simple and that, like heart failure or physical system breakdowns, psychological problems have multiple causes and diverse and diffuse symptoms.

“We must embrace organic reality, with its blurry boundaries,” he urges.

Beyond the body

He’s not alone in calling for a holistic view. The implications of mechanical thinking go far beyond human health. An understanding of life that recognizes the interconnection of parts and whole would transform science, society, policy, and the environment, according to Jeremy Lent, author of The Patterning Instinct: A Cultural History of Humanity’s Search for Meaning.

Lent is among a growing group of thinkers that believes it’s dangerous to persist in a mechanical worldview. “Every part of a living system may be mapped out but the whole affects the parts in nonlinear ways,” he says. “There is reciprocal causality, with causes and effects going in either direction continually.”

The writer told Quartz that “it’s a big mistake” to think of humans, or nature, like machines with discrete parts that can be reduced to simple elements. This fails to recognize that we evolved in a process within interrelated ecosystems in a living universe, and that a new reality is continually created by these relationships.

“Living systems are all a function of the preceding moment all the way back to the beginning of life,” Lent says. “We’re embedded in a complex web, part of a living system, and what we do has consequences we can’t predict or control.”

The danger of the mechanical worldview, he believes, is that it leads to misguided science and policy. “If we see nature as a machine, we impose no ethical limitations on human action and could destroy the very systems we depend upon for survival,” Lent says. “For example, rather than change human habits based on evidence of climate change, there’s talk in respected scientific journals about geo-engineering, basically changing nature to solve problems we created. People would rather change the planet itself than our own patterns and it could be disastrous.”

Nothing new under the sun

Both Western and Eastern philosophical traditions discuss a shifting universe in a perpetual state of flow and transformation. Understanding that dynamism is the basis of illumination, according to ancient sages.

In The Tao of Physics (pdf), theoretical physicist Fritjof Capra discusses parallels between physics and ancient philosophies, arguing that enlightened Taoist and Buddhist thinkers of yore understood and accurately described notions introduced by Albert Einstein in the 20th century, like space-time and the theory of relativity. In modern physics, he writes, matter is not passive and inert, but:

in a continuous dancing and vibrating motion whose rhythmic patterns are determined by the molecular, atomic, and nuclear structures. This is also the way in which the Eastern mystics see the material world. They all emphasize that the universe has to be grasped dynamically, as it moves, vibrates and dances; that nature is not in a static, but a dynamic equilibrium.

From a physics perspective, “the existence of matter and its activity cannot be separated,” Capra says. Life is process. Parts can’t reveal how the evolving interacting whole will work.

A risky business

Machine metaphors make sense in a society attached to devices. We want to upgrade our brains like computers, hack our lives like programs, map everything from the genome to the cosmos, then fix or manipulate bad bits.

Still, as Nesse warns, metaphors are limited. We cling to the mechanical view for fear that acknowledging mystery plunges us back in the dark days of the soul, he posits. Yet admitting organic complexity isn’t the same as relegating unknowns to religious notions. Rather, it allows for deeper scientific exploration and a wider search for the relationships among the parts and the new realities created by their interactions, rather than assuming people work like a series of simple levers and pulleys connected with replaceable nuts and bolts.

Meanwhile, clinging to the machine metaphor risks human health and billions of dollars in misguided research, plus centuries of needless debate. The physician writes: