Contrary to traditional scientific opinion, feelings are just as cognitive as other percepts. They are the result of a most curious physiological arrangement that has turned the brain into the body’s captive audience. Feelings let us catch a glimpse of the organism in full biological swing, a reflection of the mechanism of life itself as they go about their business. Were it not for the possibility of sensing body states that are inherently ordained to be painful or pleasurable, there would be no suffering or bliss, no longing or mercy, no tragedy or glory in the human condition.

-Antonio R. Damasio in Descartes’ Error

Descartes’ error, as meant by neurologist Antonio R. Damasio in this book, and one that has insinuated itself deeply into mainstream thought, is as he puts it: “the abyssal separation between body and mind, between the sizable, dimensioned, mechanically operated, infinitely divisible body stuff, on the one hand, and the unsizable, undimensioned, un-pushpullable, nondivisible mind stuff; the suggestion that reasoning, and moral judgment, and the suffering that comes from physical pain or emotional upheaval might exist separately from the body. Specifically: the separation of the most refined operations of mind from the structure and operation of a biological organism.”

In other words: thinking is inescapably a biological process. It is expressly not true, as many people take for granted, that “thinking, and awareness of thinking, are the real substrates of being.”

Moreover, Damasio attacks the traditional notion that reason is cool and pristine while emotion is irrational and fiery and never the twain shall meet. He demonstrates persuasively and exhaustively that not only does emotion actively guide our reasoning process, but that reasoning is inextricably entwined to the “low-level” brain regions including the hypothalamus and brain stem, responsible for the regulation of emotions and feelings, as well as the “high-level” prefrontal cortices responsible for language and abstract intellectual skills. In fact, according to Damasio, “feelings” are the windows to the body’s ever-changing “landscape” of its current state. This point is further elaborated in Damasio’s later book, “The Feeling of What Happens: Body and Emotion in the Making of Consciousness” to show that “feelings” form the “core” of our individual identities, and is hence, in a sense, the “real substrates of being”.

One of the strongest points made in the book is that it is futile and meaningless to think of the mind and the body, or even the brain and the body, as separate entities. The mind is derived from the entire organism as a whole, and not just its brain or nervous tissue while the organism interacts with the environment as an ensemble, instead of interacting with the body alone or the brain alone. Conversely, the body offers more to the brain than mere life-support: the brain constructs evolving representations of the body as it changes under chemical and neural influences, while signals flowing from the brain to the body in response to these representations alter the body which in turns updates the representations held in the brain. It is from this complex interaction that the thing we call “mind” is derived.

Another major topic is Damasio’s “somatic-marker hypothesis”. Since the human brain is understandably limited in its capacity to iterate through every possible eventuality and thereby perform an exhaustive cost-benefit analysis for every decision that needs to be made, Damasio theorizes that by attaching “feelings” either positive or negative to possible decisions, in effect producing the effect that we call “gut feeling” which automatically disqualifies decisions with negative “feelings” attached to them, somatic markers can help us to drastically reduce the number of possibilities that we need to consider and speed up the reasoning process. Damasio says that while some of the somatic markers are innate, the majority of them are probably learned in the course of life.

Several other intriguing points are made on the side: for example, Damasio denies the commonly believed idea that thought is composed of words, from which premise some philosophers have argued that language is essential for thought. He stresses that thought is composed of images (not necessarily just visual images as it includes olfactory, auditory images etc.) and reminds us that both words and symbols and based on “topographically organized representations” that can become images. Another is when he notes that genes precisely determine the evolutionarily old sectors of the human brain and specifies that these innate circuits exerts “a powerful influence on virtually the entire set of circuits that can be modified by experience.” Hence, while we can choose to hold our breath and swim underwater, doing so does nothing to alter our innate and powerful instinct to breathe.

The theories and ideas Damasio present is enlivened and illustrated by various case studies involving patients with neurological impairments. Particularly intriguing is the case involving Elliot who suffered a brain tumor that damaged the frontal lobes of his brain. Upon recovery, Elliot seemed to retain his basic intellectual and linguistic abilities and in fact passed virtually every psychological test his doctors could throw at him, yet he had lost his ability to function effectively in society. In effect, he has lost the ability to “feel” emotions while curiously retaining the intellectual knowledge of what emotions are, making him the very epitome of the cool-headed rational thinker, but one who is unable to make effective decisions. I also found that the descriptions of patients suffering from anosognosia, in which patients suffer paralysis of their limbs and yet deny that they condition is abnormal, and aphasia, in which patients report not seeing an object and yet behave in all other respects as if they are able to see the object, gave me quite a bit of food for thought on how consciousness works.

The price of all of this information is that the book is by no means an easy text to read and digest, and I suspect that most readers will probably forget the specifics of the brain structures and neural circuitry that Damasio takes such pains to describe in detail soon after reading the book. Yet a more serious criticism is that the author is sometimes startlingly naive with regards to the philosophical and sociological implications of his ideas.

For example, he assures us that “understanding the neurobiological mechanisms behind some aspects of cognition and behavior does not diminish the value, beauty, or dignity of that cognition and behavior“. Fair enough though he doesn’t explain exactly why this is so, but he later goes on to say that “although biology and culture often determine our reasoning, directly or indirectly, and may seem to limit the exercise of individual freedom, we must recognize that humans do have some room for such freedom, for willing and performing actions that may go against the apparent grain of biology and culture. Some sublime human achievements come from rejecting what biology or culture propels individuals to do.” Certainly, while some individuals may indeed be propelled by drives that stand apart from the norm in biological and cultural terms, I do not see how any individual can be “free” of his personal and unique biological and cultural programming.

In other areas, Damasio does acknowledge the practical implications of neurological findings on how we construe morality for example, as when he says that “the solution to the problem of social violence will not come from addressing only social factors and ignoring neurochemical correlates, nor will it come from blaming one neurochemical correlate alone. Consideration of both social and neurochemical factors is required, in appropriate measure.”

However these failures do not detract from the primary purpose of this book, which is to unequivocally establish that emotion and feeling are central to human cognition and consciousness. Also I particularly credit Damasio with successfully arguing against the traditional but often nonsensical distinction between “psychological” and “neurological” diseases, with all of the associated implications on how we treat these diseases and ascribe moral responsibilities for sufferers. For these reasons, as well as the sheer wealth of information here, Descartes’ Error would in my opinion make an worthy addition to the bookshelf of anyone who is sincerely interested in human cognition.