All living things need to protect and maintain a minimum functioning structure to survive. An animal deprived of functioning limbs, or a plant deprived of leaves, will soon die.
In addition, all organisms need to regulate a complex set of interacting metabolic chemical reactions.
From the simplest unicellular organisms to the most complex plants and animals, internal processes operate to keep conditions within tight limits to allow these reactions to proceed. Homeostatic processes act at the level of the cell, the tissue, and the organ, as well as for the organism as a whole.
Maintenance of homeostasis requires a continuing input of energy in the form of food for animals, and sunlight for plants. If the energy needed to maintain homeostasis exceeds the energy input, the organism will die once its reserves are exhausted. In terms of energy expenditure, you’ve got to keep running just to stay still.
In addition to maintaining structural integrity and metabolic stability, a juvenile organism will have a secondary priority to grow, and an adult organism a secondary priority to reproduce. But without homeostasis, these secondary aims cannot be achieved.
Conscious and unconscious homeostasis.
Non-sentient organisms, such as plants and bacteria, maintain homeostasis by purely mechanistic processes, using automatic feedback in the same way that a centrifugal governor mechanism maintains a steady speed for a steam engine. Even in sentient animals, many homeostatic processes are unconscious, and we have no awareness of their operations.
|Automatic feedback mechanism|
But the game completely changes when sentience comes into the picture. Two non-mechanistic factors come into play - qualia and intentionality - which allow far more adaptive homeostatic control strategies than purely automatic feedback loops.
Qualia (singular quale) are qualitative experiences including experiences of suffering such as thirst, hunger, fear, pain and so on.
Intentionality is the property of being ‘about’ something, of having 'an intentional object'.
So the quale of thirst forces the mind to become obsessively intentional about water, the quale of hunger forces the mind to become similarly intentional about food, and the qualia of pain and fear force the mind to become intentional about avoiding the causes of these unpleasant sensations (objects of aversion).
Did sentience evolve, or was it co-opted?
Now the interesting thing is that neither qualia nor intentionality are physical phenomena (as was first pointed out by the Victorian physicist John Tyndall 140 years ago). Neither are they in any sense mechanistic phenomena.
Consequently, there is no known process by which sentience could have arisen by Darwinian evolution. Evolution can account for the physical structure of the bodies of sentient beings and their automatic homeostatic control mechanisms, but it cannot bridge the explanatory gap between the physical and the mental.
As Thomas Nagel argues, the materialist neo-Darwinian conception of nature is incomplete, because it cannot adequately explain the appearance of consciousness.
So if sentient minds haven’t evolved, have they nevertheless been co-opted by evolutionary processes to improve the homeostatic behavior of animals? Suffering, unpleasant though it may be for the individual, has survival and evolutionary advantages for the species.
To quote Richard Dawkins:
"The total amount of suffering per year in the natural world is beyond all decent contemplation. During the minute that it takes me to compose this sentence, thousands of animals are being eaten alive, many others are running for their lives, whimpering with fear, others are slowly being devoured from within by rasping parasites, thousands of all kinds are dying of starvation, thirst, and disease. It must be so. If there ever is a time of plenty, this very fact will automatically lead to an increase in the population until the natural state of starvation and misery is restored."
Mental states such as suffering, unsatisfactoriness and pleasure are qualitative subjective experiences, which carry strong immediate meanings, and do not exist in automata - mechanistic systems such as relay networks or computers.
It is for this reason that complex animals have evolved neural structures which attract and capture minds. Fundamentally, it is the suffering and grasping of their minds - the need to avoid pain and seek pleasure - that provides the driving force for survival and reproduction of complex animals. The physical body enters into a symbiotic relationship with a non-physical mind.
In Buddhist philosophy, the mind of a sentient being is not a product of biological processes, but something primordial which has existed since beginningless time, and which will be drawn into another body once the present one has died. But reflecting on Richard Dawkins' description of the horrors of Samsara, it's surprising that sentient minds allow themselves to be co-opted by biological systems again and again. Maybe they've got no choice, maybe they're deluded, or maybe they just don't know how to get out.
The brain is a device which has evolved to delude the mind.
It could also be argued that in addition to biochemical and physiological mechanisms for maintaining homeostasis, evolution has also given sentient beings a psychological homeostatic mechanism by constructing the illusion of a stable self, which can and must be maintained.
This false sense of a stable self is, of course, a delusion, though from the evolutionary point of view, a very useful one.
Survival advantages of sentience
In evolutionary terms, any adaptation or feature must have some selective benefit for the organism that possesses it. Obviously, a physical body equipped with sentience will have an improved chance of surviving to propagate its genes over any mindless competitor which is not deterred by pain or motivated by pleasure.
But what does the mind gain from this symbiotic association? Usually little or nothing.
When the life of the biological partner comes to an end, the mind has to endure the sufferings of death and then leave its home, being unable to take anything with it. It must then enter the unstable hallucinatory state of the bardo, and perhaps soon after find a new body.
Or even worse, if it doesn't find a new body quickly, it may stay in a nightmarish state of karmically induced hallucinations - a perpetual bad trip that lasts indefinitely: 'for in that sleep of death what dreams may come...'.
Parasitic body, parasitized mind?
In Buddhist terminology these minds are wanderers or migrators in samsara (the realms of suffering and delusions). The mind is non-evolved and non-evolving, at least not by the normal processes of natural selection. The body uses the mind for its own purposes, not vice versa as we may like to imagine.
So, perhaps the relationship between mind and body is more one of parasitism than symbiosis. The biological body gets a better chance to propagate itself. But the mind has to endure dukkha - the ever-changing experiences of craving, suffering and attachment, that the body imposes upon it in order to force it to do what is necessary for survival, competition and reproduction.
Homeostasis is a mug's game
Since maintaining homeostasis is like running to keep still, sooner or later the body's systems will wear out, with the inevitable results that the Buddha observed on his ride outside the palace...
|The Four Sights|
and Can you debiologize yourself?