… without taking purpose into account, which he addresses through Biology’s Second Law, homeostasis. From J. Scott Turner in Purpose and Desire: What Makes Something “Alive” and Why Modern Darwinism Has Failed to Explain It:
away. And the uncomfortable question is this: what if phenomena like intentionality, purpose, and design are not illusions, but are quite real—are in fact the central attributes of life? How can we have a coherent theory of life that tries to shunt these phenomena to the side? And if we don’t have a coherent theory of life, how can we have a coherent theory of evolution? This is the hard nut that has to be cracked, and this leads me to the other theme I develop throughout this book: the hammer that will crack the nut of a coherent theory of life will be the largely misunderstood, widely trivialized, but profound concept of homeostasis: what I call Biology’s Second Law. (Kindle Locations 530-536)
…
[The Second Law] has a handy and well-known name—homeostasis*—which is usually dryly defined as “a state of internal constancy that is maintained as a result of active regulatory processes.” the concept is a central one for the science of physiology, of how living things work, to borrow from one author’s pithy description.(Kindle Locations 546-549).
…
… homeostasis stands today as one of the least understood and most widely trivialized concepts in modern biology. This seems at first to be a startling thing to say. If homeostasis is the foundational principle of physiology, we should have a pretty good idea of what it means. But we don’t, and the obstacle is clear: it’s mechanism. When physiologists speak of homeostasis, their reflex is to delve deeply into the delicious details of mechanism—of, say, the body’s “thermostat,” as if the body were a house controlled by a machine. In other words, to study homeostasis is to dig into the realm of the mechanic, which, by definition, is concerned primarily with machines. This invites the question: is life in fact a machine? Spend any time with something living, and you will see instantly that the answer is both yes and no. (Kindle Locations 553-559).
Widespread avoidance of these concepts is not so startling if we consider this: The concepts of agency, purpose, and intentionality are not problematic for life as we know it. We cannot observe life without noticing them. But discussing them is deadly to naturalism, as we can see from the incoherent ways by which naturalism (nature is all there is) attempts to cope with them.
See also: Is a sense of purpose (agency) what makes life special?
What can we hope to learn about animal minds?
and
Post-modern science: The illusion of consciousness sees through itself