Antonio Damasio is a neuroscientist with a philosophical bent. His earlier books were: 

• Descartes’ Error: Emotion, Reason, and the Human Brain
• The Feeling of What Happens: Body and Emotion in the Making of Consciousness
• Looking for Spinoza: Joy, Sorrow, and the Feeling Brain
• Self Comes to Mind: Constructing the Conscious Brain.

In The Strange Order of Things, he emphasizes the role of homeostasis in making life possible. Here’s one definition:

[Homeostasis is] a property of cells, tissues, and organisms that allows the maintenance and regulation of the stability and constancy needed to function properly. Homeostasis is a healthy state that is maintained by the constant adjustment of biochemical and physiological pathways. An example of homeostasis is the maintenance of a constant blood pressure in the human body through a series of fine adjustments in the normal range of function of the hormonal, neuromuscular and cardiovascular systems.

Damasio explains how, billions of years ago, the simplest cells began to maintain homeostasis, and thereby survive and even flourish, using methods, including primitive forms of social behavior, that are similar to methods used by complex organisms like us. He also emphasizes the role of feelings in maintaining homeostasis. He doesn’t suppose that bacteria are conscious, but points out that they do react to their surroundings and changes in their inner states. He argues that organisms only developed conscious feelings of their surroundings and inner states as nervous systems evolved. He thinks it is highly implausible that a human mind could function inside a computer, since computers lack feelings and feelings are a necessary part of human life. Furthermore, Damasio concludes that culture has developed in response to human feelings. Culture is a complex way of maintaining homeostasis.

I’ll finish with something from the publisher’s website written by the British philosopher John Gray:

In The Strange Order of Things, Antonio Damasio presents a new vision of what it means to be human. For too long we have thought of ourselves as rational minds inhabiting insentient mechanical bodies. Breaking with this philosophy, Damasio shows how our minds are rooted in feeling, a creation of our nervous system with an evolutionary history going back to ancient unicellular life that enables us to shape distinctively human cultures. Working out what this implies for the arts, the sciences and the human  future, Damasio has given us that rarest of things, a book that can transform how we think—and feel—about ourselves. 

I can’t say the book changed how I think about myself. That’s because for some years I’ve thought about myself as a community of cells. It’s estimated that an average human body is composed of some 37 trillion cells and contains another 100 trillion microorganisms necessary for survival. Once you start thinking of yourself as a community of cells, adding homeostasis to the mix doesn’t make much difference.

For more on The Strange Order of Things, see this review for The Guardian and this article John Gray wrote for Literary Review.