Daniel W McShea in Aeon Magazine: Why do rocks fall? Before Isaac Newton introduced his revolutionary law of gravity in 1687, many natural scientists and philosophers thought that rocks fell because falling was an essential part of their nature. For Aristotle, seeking the ground was an intrinsic property of rocks. The same principle, he argued, also explained why things like acorns grew into oak trees. According to this explanation, every physical object in the Universe, from rocks to people, moved and changed because it had an internal purpose or goal.
Modern science has rejected this ‘teleological’ way of thinking. In the 17th and 18th centuries, scientists and philosophers began to chip away at Aristotle’s seemingly ‘spooky’ notion of intrinsic causes – spooky because they suggested that rocks and creatures were guided by something not entirely material. For those who rejected these Aristotelean explanations, such as Thomas Hobbes and René Descartes, organisms were simply complex machines animated by mechanisms. ‘Life is but a motion of limbs,’ wrote Hobbes in his Leviathan (1651). ‘For what is the heart, but a spring; and the nerves, but so many strings; and the joints, but so many wheels, giving motion to the whole body.’ The heart does not have the goalof circulating blood. It’s just a spring like any other. For many thinkers at the time, this view had real explanatory benefits because they knew something about how machines worked, including how to fix them. It was in this intellectual environment that Newton developed a powerful mechanical worldview, based on his discovery of gravitational fields. In a Newtonian universe, internal purpose doesn’t cause rocks to fall. They just fall, following a law of nature.
Mechanistic explanations, however, struggled to explain how life develops. How does a grass seed become a blade of grass, in the face of endless disturbances from its environment? Long after the mechanistic revolution, the philosopher Immanuel Kant confronted the stubborn problem of teleology and despaired. In 1790, he wrote in the Critique of Judgment that – as commonly paraphrased – ‘there will never be a Newton for a blade of grass.’ Less than a century later, with the publication of On the Origin of Species (1859), Charles Darwin seemed to crack the problem of biological teleology. Darwin’s ideas about natural selection appeared to explain how organisms, from grass seeds to bats, were able to pursue goals. The directing process was blind variation and the selective retention of favourable variants. Bats who sought moths and had an ever-improved capacity to track and catch them were favoured over those who were less goal directed and therefore had lesser capabilities. Though natural selection seemed to illuminate what Descartes, Hobbes and Kant could not, Darwin’s theory answered only half the problem of teleology. Selection explained where teleological systems like moth-seeking bats come from but didn’t answer how they find their goals.
So, how do goal-directed entities do it, moment by moment? How does an acorn seek its adult form? How does a homing torpedo find its target? Mechanistic thinking struggles to answer these questions. From a mechanical perspective, these systems look strangely future oriented. A sea turtle, hundreds of miles out to sea, can find the beach where it was born, a location that lies in its future. A developing embryo, without any thought of the future, constructs tissues and organs that it will not need until much later in life. And both do these things persistently: carried off course by a strong current, the sea turtle persistently finds a trajectory back toward its natal beach; despite errors in cell division and gene expression, an embryo is able to make corrections as it grows into its adult form. How is this possible?
Even though mechanistic thinking has failed to solve this teleological problem, it still dominates scientific thought. Today, we invoke mechanism to explain almost everything – including human goal-directed behaviour. To explain the growth of an acorn, we look to mechanisms in its genes. To explain the ocean voyages of a sea turtle, we look to mechanisms in its brain. And to explain our own thoughts and decisions, we focus on neural pathways and brain chemistry to explain decision-making. We explain behaviour in terms of evolutionary needs, such as survival or reproductive success. We may even think of our genes as ‘blueprints’. For some 20th-century thinkers, such as the US psychologist Burrhus Frederic Skinner, human brains are purely mechanistic. Skinner denied that people have goals at all. More recently, the primatologist Robert Sapolsky, based at Stanford University, and others have painted a mechanistic picture of us that denies we have free will.
And yet, despite centuries of rejection, teleology has not been banished. Most of us still have a deep intuition that there is more to our thinking and action than mere mechanisms. The feeling of being in love isn’t just the mechanical outcome of neurochemistry. We want to believe it is driven by our wants and intentions. Some of us, especially if moved by religious or spiritual impulses, might even see goals in the larger universe: ‘I am here for a purpose,’ you might think to yourself. For many, a world of pure mechanism seems insufficient. And beyond our intuitions about teleology, there are countless areas of science where teleological explanations are commonly deployed, even without any explicit recognition of them. Consider the debate over which parts of a genome are ‘functional’ (ie, they perform roles that are beneficial to an organism) and which are ‘non-functional’ (ie, useless remnants of evolution). The very idea that a gene can either be functional or non-functional implies that certain genes aim towards certain results, or have certain purposes for the organism, while others have no ends and are merely purposeless junk. So, even beyond our intuitions, teleology is so deeply entwined with science that there will be no getting rid of it anytime soon.
So, caught between modern science and our intuitions about teleology, we seem to have only two ways of explaining the apparent goal directedness in some systems: teleology or mechanism. Both are troublesome. Both are inadequate. In recognition of this problem, philosophers of biology and others have, in recent decades, been struggling to find an alternative. We believe we have found it: a third way that reconciles Aristotelian thinking about goal directedness with the mechanistic view of a Newtonian universe. This alternative explains the apparent seeking of all goal-directed entities, from developing acorns and migrating sea turtles to self-driving cars and human intentions. It proposes that a hidden architecture connects these entities. It even explains falling rocks.
We call it ‘field theory’.
The notion of ‘fields’ was originally developed by physicists such as Newton, Michael Faraday, Richard Feynman and others. In physics, the concept has been used to explain gravity, electromagnetism, and particle interactions in quantum theory. But fields have also been used in biology to explain the development of living things. In the mid-20th century, the Austrian biologist Paul Weiss proposed that, within an embryo, large ‘morphogenetic fields’ directed the behaviour of cells inside them. Together, these pioneers in physics and biology showed how objects in the Universe can be directed by often-invisible and large-scale external structures. Our version of field theory takes this as its starting point.
More here.
