Utility and Pain in Biology

1. The fact that pain states are associated with damaging experiences is the result of natural selection. Pain is an adaptive trait and improves the survival value.

2. Once pain improves the survival value, it becomes a driving force of evolution. This doesn’t exclude that (in other instances) pain is only a by-product of evolution. It also doesn’t exclude that evolution could have taken a different path.

3. The importance of learning mechanisms increases with the lifetime of the creatures and with the complexity of the environment. The behaviour of long-lived creatures is shaped by painful experiences acting on these mechanisms.

4. A wide range of emotions enhances the capability of the creature to respond to the environment. A wide range of emotions implies a high degree (intensity and duration) of pain. A high degree of pain is therefore superior with regard to biological fitness

Pain as byproduct

The same allele can produce senseless pain or superior adaptation depending on the combination with other alleles, i.e. it produces either handicapped or advantaged individuals with regard to biological fitness. If the result is a net reproductive advantage, then the allele will tend to increase in frequency in the population.

The distribution of pain

1) Certain kinds of pain are prevented or mitigated by the phenomenon of biological altruism.

2) The general trend is an increasing inequality (injustice) in the distribution of pain.

1. Introduction

Starting point

The capability to feel pain increases with evolution and seems not to be limited.

Type of problem

1. What is the role of pain in biology? Is it a necessary part of biological evolution?

2. How does injustice (the distribution of pain) evolve?

2. The Assessment of Pain

Terminology

The term suffering includes all kinds of preference-frustrations, such as hunger, sexual deprivation etc. whereas the term pain is often restricted to tissue damage. The long-term goal is to understand the evolution of suffering. The concentration on pain corresponds to the actual priority in research.

Theses

1) Fishes cannot experience pain, fear or other emotions [Rose].

2) Fish – and even some crustaceans – are consciously aware of pain [Braithwaite].

3) A sound assessment of the probability that conscious states occur in fish species will require knowledge of their forebrain neuroanatomy and an understanding how such structures mediate behavioral responses [Chandroo, 281-295].

4) Many researchers point to a line between vertebrates and invertebrates. Pain is uncertain in all but the most advanced invertebrates (octopus/squid). It is virtually certain that some invertebrates (amoebas) are not sentient [DeGrazia]

5) Probably all normal vertebrates are capable of feeling pain, and probably all invertebrates (with the exception of cephalopods) are not [Bateson].

6) Most invertebrates (particularly insects) do not feel pain [Senate of Canada].

Summary

1) Vertebrates

a) As a general rule one can say that pain in vertebrates is probable

b) There are exceptions (like fishes) where the issue is controversial

2) Invertebrates

a) As a general rule one can say that pain in invertebrates is improbable

b) There are exceptions (like cephalopods) where the issue is controversial

c) In some species (like amoebas) it is virtually certain that pain doesn’t exist.

3. Biological Utility

Synonyms:

1. Biological utility function

2. Utility function of life

3. God’s utility function

The utility function of life, that which is being maximized in the natural world is DNA survival. But DNA is not floating free: it is locked up in living bodies and it has to make the most of the levers of power at its disposal. (…) Each change is due to evolution: “Each generation is a filter, a sieve: good genes tend to fall through the sieve into the next generation; bad genes tend to end up in bodies that die without reproducing. (…) Animals are survival machines – robot vehicles blindly programmed to preserve the selfish molecules known as genes” (Dawkins, 2007).

1. God's utility function is a phrase coined by Richard Dawkins in his book River Out of Eden (…). Dawkins uses this phrase to expound the Gene-centered view of evolution by equating the phrase to the meaning of life or the purpose of life. This is the why question about life which philosophers and theologians have been pondering in vain for ages, and is a counterpart to the how question about nature which engineers have been able to resolve successfully (…)

2. Dawkins rephrases the word purpose in terms of what economists call a utility function, meaning "that which is maximized". Engineers often investigate the intended purpose (or utility function) of a piece of equipment using reverse engineering. Dawkins uses this technique to reverse-engineer the purpose in the mind of the Divine Engineer of Nature, or the Utility Function of God.

3. According to Dawkins, it is a mistake to assume that an ecosystem or a species as a whole exists for a purpose. In fact, it is wrong to suppose that individual organisms lead a meaningful life either. In nature, only genes have a utility function – to perpetuate their own existence with indifference to great sufferings inflicted upon the organisms they build, exploit and discard. As hinted at in chapter one, genes are the supreme lords of the natural world. In other words, the unit of selection is the gene, not an individual, or any other higher-order group as championed by proponents of group selection.

(God’s Utility Function, Wikipedia)

4. The Evolution of Pain

4.1 Pain as Adaptive Trait

Pain states are causal states

Human beings do experience pain, and there is a correlation between incidents of pain and tissue damage. Either this trait is present in the human phenotype because it was selected for, or its presence is a byproduct of selection for some other trait. In order for there to be selection for a trait, that trait must make a difference to the organism possessing it: pain states must be causal states if they are to be selectively advantageous. Pain accompanies too wide a range of physical phenomena to be a byproduct of selection for something else. Thus pain states are causal states. [Saidel]

Pain is an adaptive trait

Subjective sensations, such as pleasures and pains, are adaptive traits of organisms.

So far as we know, there is no fundamental physical reason why pleasure is attached to some circumstances and pains to others. We might have evolved to find the sensation of having a finger caught in a door intensely pleasurable, just as dung-flies may well relish the smell of excrement. On the evolutionary hypothesis, the fact that pleasures are generally associated with beneficial, and pains with detrimental, experiences, is the result of natural selection among random variations: those individuals who happen to have an association of this kind have higher biological fitness than those who have no such association, or the reverse association (No Pain - no Gain by David B.)

Pain is a teacher

1) Pain is a teacher, the headmaster of nature's survival school and like any teacher, it requires pupils with an ability to learn.

Sensations of pain are a key component of human survival, keen intelligence and creativity. From Best Analgesic is Hope , Why We Hurt, The Natural History of Pain, by Frank T.Vertosick, Cerebrum: The Dana Forum of Brain Science, Vol.2, No.4:Fall 2000.

2) Pain is realised in biology as an educational tool. Vertebrates are relatively long-lived creatures and learning shapes their behaviour. In contrast, invertebrates are short-lived and their behaviour is largely genetically determined. There is less pressure for the evolution of pain here (Animal Angst: No brain, no pain?, The Hindu, Mar 10, 2005)

Pain is a solution rather than a problem

The capacity for pain is certainly beneficial. The rare individuals who cannot feel pain fail even to experience discomfort from staying in the same position for long periods. Their unnatural stillness impairs the blood supply to their joints, which then deteriorate. Such pain-free people usually die by early adulthood from tissue damage and infections. Cough or pain is usually interpreted as disease or trauma but is actually part of the solution rather than the problem. These defensive capabilities, shaped by natural selection, are kept in reserve until needed [Nesse].

Pain is analogous to a “smoke alarm”

An obstacle to perceiving the benefits of defences arises from the observation that many individuals regularly experience seemingly worthless reactions of anxiety, pain, fever, diarrhoea or nausea. The explanation requires an analysis of the regulation of defensive responses in terms of signal-detection theory. A circulating toxin may come from something in the stomach. An organism can expel it by vomiting, but only at a price. The cost of a false alarm— vomiting when no toxin is truly present— is only a few calories. But the penalty for a single missed authentic alarm— failure to vomit when confronted with a toxin—may be death. Natural selection therefore tends to shape regulation mechanisms with hair triggers, following what we call the smoke-detector principle. A smoke alarm that will reliably wake a sleeping family in the event of any fire will necessarily give a false alarm every time the toast burns. The price of the human body’s numerous “smoke alarms” is much suffering that is completely normal but in most instances unnecessary [Nesse].

4.2 Pain as Byproduct

Pain can be an accidental by-product of Darwinian selection

Compromise is inherent in every adaptation. Arm bones three times their current thickness would almost never break, but Homo sapiens would be lumbering creatures on a never-ending quest for calcium. More sensitive ears might sometimes be useful, but we would be distracted by the noise of air molecules banging into our eardrums.

Such trade-offs also exist at the genetic level. If a mutation offers a net reproductive advantage, it will tend to increase

in frequency in a population even if it causes vulnerability to disease. People with two copies of the sickle cell gene, for example, suffer terrible pain and die young. People with two copies of the “normal” gene are at high risk of death from malaria. But individuals with one of each are protected from both malaria and sickle cell disease. Where malaria is prevalent, such people are fitter, in the Darwinian sense, than members of either other group. So even though the sickle cell gene causes disease, it is selected for where malaria persists. Which is the “healthy” allele in this environment? The question has no answer. There is no one normal human genome—there are only genes [Nesse].

Nature is not interested in suffering unless it affects the survival of DNA

Genes are pitilessly indifferent to who or what gets hurt, so long as DNA is passed on:

“It is easy to imagine a. gene that, say, tranquillizes gazelles when they are about to suffer a killing bite. Would such a gene be favored by natural selection? Not unless the act of tranquillizing a gazelle improved that gene's chances of being propagated into future generations. It is hard to see why this should be so and we may therefore guess that gazelles suffer horrible pain and fear when they are pursued to the death - as most of them eventually are.
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, others are running for their lives, whimpering with fear, others are being slowly devoured from within by rasping parasites, thousands of all kinds are dying of starvation, thirst and disease. It must be so. If there is ever a time of plenty, this very fact will automatically lead to an increase in population until the natural state of starvation and misery is restored (River out of Eden, Richard Dawkins).

4.3 The Distribution of Pain

There are two opposing trends in the distribution of pain:

1. Evolution is a process of increasing differentiation, implying increasing inequalities. Not only are the various types of life unequal but also the individual members within each type. Individual inequalities increase with the evolution of the species. Complex organisms differ more from each other than simple organisms. Evolution creates unequal distributions within all dimensions of life, in particular unequal distributions of pain. With the degree of pain, the degree of injustice increases as well:

In a universe of electrons and selfish genes, blind physical forces and genetic replication, some organisms are going to get hurt, others are going to get lucky, and you won't find any rhyme or reason in it, nor any justice. The universe that we observe has precisely the properties we should expect if there is, at bottom, no design, no purpose, no evil and no good, nothing but pitiless indifference [Dawkins, 80-85]

2. Certain kinds of pain (e.g. the pain of starving or being attacked by predators) are prevented or mitigated by altruism:

Donor-recipient correlation, rather than genetic relatedness, is the key to the evolution of altruism. What is needed for altruism to evolve, is (…) that the recipients of altruism have a greater than random chance of being fellow altruists. Whether this higher than random donor-recipient correlation arises because partners tend to be relatives, or because altruists are able to seek out other altruists and choose them as partners, or for some other reason, makes no difference to the evolutionary dynamics (Biological Altruism, Stanford Encyclopedia of Philosophy).

The net result of these two opposing trends is an increasing injustice in the distribution of pain.

5. Conclusions

Pain serving the utility function

1. The fact that pain states are associated with damaging experiences is the result of natural selection. Pain is an adaptive trait and improves the survival value.

Pain as byproduct

The distribution of pain

1. Certain kinds of pain are prevented or mitigated by the phenomenon of biological altruism.

2. The general trend is an increasing inequality (injustice) in the distribution of pain.

References

1. Bateson Patrick, Which animals feel pain?

2. Braithwaite Victoria (2010), Do Fish Feel Pain?, Oxford University Press

3. Chandroo Kristopher Paul, Yue Stephanie, Moccia Richard David (2004), An evaluation of current perspectives on consciousness and pain in fishes, Fish and Fish Series, 5, Aquaculture Centre, University of Guelph, Canada

4. Dawkins Richard (1995), God's Utility Function , Scientific American, Nov., p.80-85

5. Dawkins Richard (2007), Study Notes

6. DeGrazia David, What Animals are Like

7. Nesse Randolph M., Williams George C., Evolution and the Origins of Disease

8. Rose James D. (2002), The Neurobehavioral Nature of Fishes and the Question of Awareness and Pain, CRC Press

9. Saidel Eric (2007), The Evolution of Pain, An Argument for the Causal Efficacy of Mental States, University of Southwestern Lousiana

10. Senate of Canada, Standing Committee on Legal and Constitutional Affairs (2003), Bill C-10B (Cruelty to Animals), June.12, Do Invertebrates Feel Pain?