The Rights of Flies and Fleas

A while back, I posted a link to an article by Austrian animal rights philosopher Helmut Kaplan. In response, I received a request from “Jennifer” to post my thoughts about the sentience of insects and other tiny creatures, our moral obligations toward them, and their place in animal rights advocacy. It has taken me longer than I expected to get my reply written and posted, for which I apologize.

Jennifer’s post raises five issues explicitly and one by implication. The explicit issues are these, rearranged slightly for the sake of the discussion:

    • I do wonder about their sentience.
  • What, do you think, are the interests of dust mites? Roaches? Fruit flies?


    • I wonder whether it’s as wrong to kill them as it is to kill, say, chickens or pigs.
    • I know that some animal rights thinkers have said that when it comes to insect sentience, they don’t know, so they choose to err on the side of caution. I guess that’s what I try to do too. [I believe Jennifer is referring to a 2012 statement by animal advocate and movement theorist Gary Francione on his blog The Abolitionist Approach.]
  • But I worry that it’s not necessary, and may even be counterproductive, for the movement for animal liberation to tell would-be supporters they need to start escorting fruit flies outside as much as they need to stop eating animals and animal products.


And the issue raised by implication, and which underlies her explicit questions, is this:

  • It is much more difficult to avoid harming insects and other tiny creatures than it is larger animals such as mammals, birds and fish, because:
    • They are tiny, sometimes, as in the case of dust mites, invisible to the naked eye.
    • They are multitudinous.
    • They regularly invade “our” space, including our homes.
    • They are often a nuisance, or even a danger, in ways that larger animals seldom are, biting us and our companion animals, spreading disease, getting into our homes, our beds, and our food, and in some cases, e.g. termites, damaging our houses and other wooden buildings.
    • They are the most alien in appearance and lifestyle of any land animals, so alien, in fact, that they arouse an aversion in many humans that often rises to the level of disgust or even horror.
    • They elicit almost no human empathy or sympathy; egregious cruelty to larger animals elicits a public outcry; cruelty to insects is seen as an oxymoron.
    • And finally, our societies are organized for the destruction of insects and spiders; there are no laws or customs protecting them, no insect and spider shelters, no rehab facilities; there are a plethora of private companies whose mission is to exterminate insects and spiders, but no companies whose mission is to rescue or relocate them.

First off, I want to thank Jennifer for raising an issue that receives all-too-little attention in the animal rights community. The short answer is that I agree with pretty much everything she said, including Gary’s invocation of the precautionary principle and her concern about the risks in making insects an issue in animal rights campaigns or in our personal advocacy. Sometimes, we need to prioritize, and I think that this is one of those times. All told, I think Jennifer has got it right.

Now to the long answer:


Sentience, Needs and Rights

As Jeremy Bentham, Peter Singer and others have pointed out, interests are a function of sentience.[1] All sentient beings, i.e all beings who are able to experience suffering and happiness, who dread death and long for continued life, have needs (which I think is a more accurate term than “interests”), and no being that is insentient can have needs. And whatever a sentient being has a need for, she has a right to, by virtue of the simple fact that she needs it. Sentience creates needs, all of which are based in the powerful urge that is born into all sentient beings to be alive and happy and to avoid suffering and death; these needs are inherent components of consciousness; and they create rights. If there were no inborn needs, there would be no rights. In the absence of needs, the concept of rights becomes meaningless, nonsensical.

Any other rationale for rights is either an elaboration of this fundamental truth or is wrong. The word of God, the law of karma, the principle of utility, the categorical imperative, the social contract, virtue, customs, constitutions and laws are useful only to the extent that they elucidate and implement this bedrock truth of life: Whatever a sentient being needs, she has a right to, by virtue of the simple fact that she needs it. Seen in this way, a right is simply the social expression of a need.

Before leaving this general discussion of interests and rights, and moving on to Jennifer’s questions, there are two further points about needs and rights that we should consider.

First, not every need can be met; hence not every right can be satisfied. At the most basic level, every sentient being has a right to continued life, but every sentient beings dies. The world is an enormous abattoir; the life of every sentient being is a lonely walk down the chute to the butcher’s knife. What the old spiritual says about “poor little Jesus boy” is true of us all; we are “born for to die.” That is the challenge and the tragedy of life and the inherent, irreparable moral flaw in the structure of the universe. It is a fundamental truth of life; it is the truth toward which the Christian doctrine of the Fall and the Buddhist teaching on the First Noble Truth, “Life is suffering,” point: There is a terrible amorality inextricably woven into the fabric of the universe, a terrible unconcern for the needs of beings, a failure of the universe to be in sync with our natures, a mute refusal to respect, or even to acknowledge, our rights. But the fact that a right cannot be satisfied does not mean that it should not be recognized as a right. Rights are not contingent on their prospects for fulfillment. We all have a right to what we need, even if we can never have it.

Rights are obligations that the needs of an individual place upon others. As individuals, as institutions, and as societies, we should always strive to satisfy as many rights as we can while recognizing that we will never succeed in satisfying all rights. For individuals, for institutions, ranging from families to churches, to schools and universities, to profit-making companies, to governments, and for societies as a collective whole, morality consists in meeting as many needs, satisfying as many rights, as we are able—all the while knowing that we will never meet all needs or satisfy all rights.

Sentience creates needs, needs create rights, and rights create moral obligations for those in a position to satisfy those rights, in whole or in part. We can recognize the needs of others and are motivated to meet them by compassion based upon empathy. Empathy inspires compassion and compassion inspires the desire to meet the needs of others. And genuine compassion recognizes this desire as a moral obligation. Thus, there is a moral obligation to be compassionate, a moral obligation to meet the needs of others based on our urgent desire to have our own needs met, our own longings satisfied. There is no valid distinction between practicing compassion and respecting rights. If we are compassionate, we will respect the rights of others; and if we respect the rights of others, we will act compassionately.

This obligation to others is tempered by the fact that we also have needs that must be met. The Bible tells us, rightly, to love our neighbor as ourself, not to love him more. And the Golden Rule tells us to treat others as we want to be treated, not better. In an egalitarian ethic, all sentient beings are morally equal, including oneself. Difficulties arise because at heart we all want to be treated better than everyone else. Lowering ourselves to the level of universal equality can thus feel like self-sacrifice. But there is a difference between genuine self-sacrifice and sacrificing our ego and sense of unique entitlement. To abstain from eating and wearing the products of animal enslavement and slaughter may feel to our pampered egos like sacrificing ourselves for others, and therefore, treating others better than we treat ourselves, but it is not. It is equalizing ourselves with others by recognizing our equal right to life.

We all naturally perceive ourselves as the center of the universe and consider it a grave injustice that everyone else does not agree with us; therefore, it is not easy even to understand what it means to equalize oneself with others, not to mention actually doing it on a consistent basis. But trying our best is both the basis and the nature of the moral life. A moral life is not one that is devoid of self-interest; it is one that honestly and intelligently strives to balance ones own needs with the needs of others.  Thus, while I am fundamentally a believer in nonviolence (because violence frustrates needs and violates rights), I am equally a believer in the right of every sentient being to self-defense—including the right to what is sometimes called “extended self-defense,” i.e. the right to defend others against aggression. As moral beings, we have an obligation to use the minimum amount of violence necessary to defend ourselves and others, but I believe we do have the right to use violence when there is no realistic alternative. To be an absolute pacifist (as I was for most of my young adulthood), is to pretend we live in a world that does not exist; it is to spin fairy tales that are beautiful but illusory. It is one of the tragedies of our world that there are times when violence committed for the sake of exploitation, pleasure, ego-gratification, or pure malevolence can only be stopped by countervailing violence. And pretending that this is not true, despite thousands of years of consistent historical evidence, simply cedes the world to the violent and the ruthless. Genuine morality is not about self-improvement. “You shall love your neighbor as yourself,” is not a self-help slogan designed to make us spiritually healthy the way “An apple a day keeps the doctor away,” is designed to make us physically healthy. Morality is about improving the lives of others. And to be helpful to others, our ethics must be grounded in an honest appraisal of reality. Fictions, even pure-hearted and beautiful fictions, always lead to a bad end.

Second—and this is really just a specific instance of the moral flaw in the structure of the universe—the rights of individuals often come into conflict. The right of the lion and the robin not to die of starvation conflicts with the right of the zebra and the earthworm not to be killed and eaten. And there is no way to resolve this conflict except by favoring one set of rights over another; both cannot be satisfied. My right to live in a structurally safe home conflicts with the termite’s right not to starve to death. And there is often no way to resolve this conflict that honors both my rights and the termite’s. Likewise, my right to eat safe, hygienic food conflicts with the housefly’s right to eat, defecate and lay eggs according to her nature. There is often no way to resolve this conflict that respects both sets of rights. Living beings exist in conflict with one another that all-too-often cannot be resolved without resort to violence that violates the rights, and frequently ends the life, of one or another of the parties.

The moral tragedy of life is that because we live in a structurally imperfect universe, a universe distorted by a profound moral flaw, we will of necessity not merely fail to satisfy the rights of all sentient beings, we will have to violate those rights ourselves, including the most urgent and fundamental right of all, the right to life, in the course of defending our own rights. The question thus becomes, If it is not wrong to violate the rights of others in the name of self-defense, when does self-defense become genuinely necessary, and when is it merely an alibi for cruelty committed for the sake of pleasure, convenience or laziness? Where is the line between comfort and convenience on the one hand and necessity on the other? It is a constant temptation for those with power to view even their trivial comforts and conveniences as necessities that justify violating the vital interests of the weak. Honest self-examination is among the most difficult of undertakings. But without this sort of mindfulness, it is not possible to live a moral life. Eternal vigilance is not merely the price of liberty; it is also the price of morality.

Holding this discussion at the backs of our minds, let’s now consider Jennifer’s questions:


Are Insects, Spiders and other Tiny Creatures Sentient?

I have no doubt whatsoever that they are—for three reasons: First, their behavior suggests it. Second, they have a physical mechanism capable of supporting it. And, finally, sentience conveys a considerable evolutionary advantage to any beings able to take discretionary action in their own interest.

Brian Tomasik, a computer scientist and researcher into the phenomenon of pain (He has a special interest in whether artificial intelligences or elements of computer software programs, such as characters in video games, are sentient.[2]), reviews the current scientific thinking on the sentience of insects and other invertebrates in an excellent article on his website Essays on Reducing Suffering. Tomasik summarizes his conclusions based on a survey of the current scientific literature this way: “I think recent evidence suggests that they [insects, grubs, and other tiny creatures] do experience what is defined as pain.” This evidence has been unearthed through two lines of investigation. The first, physiological, indicates that insects, grubs, and other small creatures do, in fact, have the physical apparatus to experience pain: nociceptors, a nervous system, etc. The second line of investigation is behavioral, and it reveals that insects, grubs, etc. exposed to noxious stimuli react to the administration of analgesics exactly as we would expect a being to react who was feeling pain. When given an analgesic, they become calmer, less agitated, and generally appear to be more comfortable. A third line of research, reported by pioneering cognitive ethologist Donald Griffin in his book Animal Minds: Beyond Cognition to Consciousness suggests that rather than follow pre-programed, “instinctive” instructions, many insects think through problems to find innovative responses to new situations.

In Created from Animals: The Moral Implications of Darwinism, philosopher James Rachels makes a compelling case that sentience arose far deeper in our evolutionary past than even scientists are usually inclined to believe. It seems clear to me that sentience arose at the point at which animals became physically capable of multiple responses to a stimulus, i.e, the point at which           they had to make decisions as to which of several available courses of action they would follow in any particular situation. And this occurred far below insects.

One final thought on this point: At one time philosophers seriously debated the question, “Can a flea see its own foot?” The underlying issue, of course, was, “Is size absolute or is it relational?” And the answer is, Of course a flea can see its own foot. To think otherwise is silly. Size is relational; it is not absolute. Things appear large or small in relation to the scale of our bodies. And the human scale is parochially human; it is not a universal scale. High powered microscopes have revealed that complexity does not diminish with size. Things that are so tiny as to be invisible to the unaided human eye have been shown to be stunningly complex. Consider the microchip.

To use a popular tagline in a different context, Size doesn’t matter—but architecture does. A tiny brain can be more powerful than a large one, depending on how it is organized and constructed. Today’s smartphones are many times more intelligent than early mainframe computers. And there is no reason to think that mammalian brains have the most efficient architecture in the animal kingdom. Birds, for example, have smaller brains than most mammals, but as Theordore Barber, Irene Pepperberg and other ethologists have demonstrated, they are extremely intelligent beings. The fact that, on our scale, insects have tiny brains does not argue against them being both sentient and intelligent.


What are the interests of dust mites? Roaches? Fruit flies?

Going back to the earlier part of our discussion, I think the fundamental interests of insects are identical to those of all sentient beings: achievement of happiness, avoidance of suffering, continuation of life, avoidance of death. Like all of us, they need food, water, shelter, an environment conducive to their lives and health, and a safe place to lay their eggs. More specifically, dust mites need flakes of exfoliated skin and a dry, warm environment. Roaches need a food source, such as garbage or leftover human food, water, a warm environment, and a dark, enclosed, secure space in which to live and lay their eggs. And so it goes through the various species of insects and spiders. Their needs are pretty much what we would expect them to be given their anatomy and behavior.


I wonder whether it’s as wrong to kill them as it is to kill, say, chickens or pigs.

Yes, I believe that it is as wrong to kill insects as it is to kill chickens or pigs, or human beings, for that matter. And I believe that our casual attitude toward the suffering and death of insects, spiders, grubs and worms needs to change. Their lives are of ultimate value to them and must be respected.

Nevertheless, if chickens, pigs or human beings intruded into our homes in large numbers, gave us painful, and possibly disease-laden bites or stings, violated our personal space, devoured the wood in our homes, fouled our food, and destroyed our fruits and vegetables, we would stop these incursions by whatever level of violence was needed—including lethal violence if that proved necessary. And in fact, we routinely employ violence to stop these kinds of incursions by larger animals and humans. But this violence is largely invisible to us because it is predominantly structural, rather than individual. It is violence embedded in our society in many forms, but most prominently in the form of the criminal justice system (for humans) and the various animal control systems (for animals). Not to mention that the mere processes of urbanization and suburbanization serve to keep larger animals and humans separated. There are fewer large animals in downtown Atlanta than there are in the Georgia pine forests. By contrast, individual violence plays a much larger role in defense against insects, spiders, grubs and worms; hence, it is both more visible and more a matter of individual, rather than societal, responsibility.

In the preliminary discussion, I defended the right to self-defense. That right is not limited to defense against malicious incursions; it extends to all incursions based on their effects, not their motivation. This again is part of the moral flaw built into the structure of the universe—and one that we cannot wish away.

It is not possible to avoid unpleasant and sometimes dangerous interactions with insects and spiders in the way that we can avoid unwanted interactions with larger and less populous animals. And because of their small size and great numbers, it is often not feasible to protect ourselves from them by less than lethal means. And so, it is sometimes necessary to kill insects to protect ourselves.

Recognizing that killing or otherwise harming them is both a violation of their rights and sometimes necessary, I try to kill, injure, or disrupt the lives of insects and spiders as seldom as possible. But when necessity demands, I do it.

In this regard, I consider myself fortunate to live in a temperate climate with moderately cold winters (average highs in the 50s, average lows in the 30s, frequent freezes, several inches of snow) that last about four months and keep insects and spiders pretty much absent for about half the year—and keep their numbers moderate the other half. If I lived in central Africa, or even on the Gulf Coast of the United States, I would have to kill far more often than I do in the mountains of Western Maryland. If I lived in the country, I might have to kill more often than I do living in town. And if I lived in an apartment building, I might have to kill more often than I do living in a detached house. But if I lived in any of these places, I would do what I had to do.

The issue, as I said before, is where to draw the line between necessity and convenience, danger and annoyance. In many regards, each of us has to draw that line for themselves. The following are a few examples of where Patti and I draw it:

  • We try to keep the house as clean and free of crumbs and bits of food as possible.
  • When individual, or just a few, insects come into our home, we either leave them alone or try to catch them and release them outdoors.
  • Should too many insects, say ants, come in at one time for this to be feasible, we kill them.
  • We put down nonlethal barriers, e.g. cayenne pepper, to keep ants out of the house.
  • We have poison buried around our frame house to prevent termites from entering. (The company uses poisons that are not lethal to vertebrates and in any event buries them where birds, dogs, cats, raccoons and the like cannot get to them.)
  • We do not use pesticides to protect grass, flowers or ornamental shrubs from insects—ornamentation is a convenience, not a necessity.
  • We would kill insects, individually, who are causing extensive damage to a vegetable garden, but we would not kill them if the damage were minor, and we would not spray pesticides.
  • We do, however, eat commercially grown fruits, vegetables, grains, and pulses, although we know that the plants were sprayed with insecticide.
  • We use repellant to keep mosquitos off. If one alights anyway, we shoo him off. If he persists, we kill him. If a swarm lights on us, we shoo away as many as we can and kill those who are persistent. If we can conveniently do so (if, for example, we are in our backyard), we go inside so as not to have to kill them.
  • Patti is allergic to the venom of bees, wasps, and similar insects (She goes into anaphylactic shock.), and so I break up any nests that we find on or near the house. If she were not allergic, we would do this only if there were a large number of bees, wasps, or whatever frequently coming and going.
  • We try to be careful when walking, to avoid inadvertently stepping on ants or other insects.
  • We drive cars, and ride in them, even on trips that are for pleasure or convenience rather than strict necessity, although we know that—especially on summer nights—we will kill insects by doing so.
  • We regularly launder our clothing and bedclothes, although in doing so we are almost certainly killing dust mites.

I recognize that there is much room for disagreement with the items on this list. But they represent where Patti and I feel most comfortable (or least uncomfortable) ethically, at least at present. In summary, we try to follow the following principles as much as we are able:

  • Exclusion: keeping insects and spiders out of the house whenever possible.
  • Removal: capturing and releasing outdoors individual insects who come into the house—whenever this is doable.
  • Ignoring: leaving insects and non-poisonous spiders alone whenever exclusion fails, removal is not possible, and the intruders are only a distraction or a minor annoyance.
  • Killing: as a last resort whenever exclusion fails, and removal and ignoring are not feasible.

Every time I kill an insect or spider, I am acutely aware that I am taking the life of a being who wants to live as much as I do, and so I try very hard to kill them as seldom as possible. I am also aware that my awareness and regret are no comfort to the being whose life I am taking.

I believe that when society has evolved to the point that the sentience and moral worth of insects, spiders, worms, grubs, and other small beings are generally recognized, we will collectively, through our institutions, work out ways to live more harmoniously with them, ways that will sharply reduce (although not eliminate) the need for individuals to kill insects.


I know that some animal rights thinkers have said that when it comes to insect sentience, they don’t know, so they choose to err on the side of caution. I guess that’s what I try to do too.

I think that applying this precautionary principle is always a good practice. As I said, I am convinced that insects and spiders are sentient, and so I proceed on that basis, but wherever there is reasonable doubt we should always do our best to take the action that under a worst-case scenario would cause the least harm.

I worry that it’s not necessary, and may even be counterproductive, for the movement for animal liberation to tell would-be supporters they need to start escorting fruit flies outside as much as they need to stop eating animals and animal products.

I think that for the foreseeable future, we should direct our campaigns toward larger animals, for whom the public has more affinity, and hence greater empathy and sympathy, and who do not present some of the difficulties presented by insects. We must portray animal rights as doable within the context of a personally and socially normal life, not as some kind of iron man triathlon that will take over their lives and subject them to an ascetic discipline that will be all but unendurable.

At least for the present, devoting scarce time and resources to convincing the public that ants and spiders are morally equivalent to dogs and cows would be counterproductive. First, we have to get people to understand that dogs and cows are morally equivalent to human beings—and that is hard enough. When we are well on the way to achieving that objective we can begin to devote attention to changing the public view of insects and spiders.

We should, however, always be clear and consistent on the point that all sentient beings deserve our compassion and concern. And if asked, we should say what we believe. If someone, whether friend or stranger, sees me picking up stranded earthworms from the sidewalk and placing them on the grass and asks, Why, I will explain truthfully.  If they do not ask, then depending on the situation I will either remain silent and let my example speak for me or I will say simply, “He wants to live as much as we do,” and leave it at that.


[1] I use “sentience” and “consciousness” interchangeably. I think the idea that you can be sentient (able to experience pleasure and pain) without being conscious (aware that one is experiencing pleasure or pain), which is popular in some quarters, draws a distinction that does not exist in nature. Following Bentham, I also use “pleasure” and “happiness” interchangeably, and likewise “pain” and “suffering.”


[2] The question of whether machines (or more often, software) can be sentient is a hot topic in the fields of neuroscience and artificial intelligence. The notion that machines (or software) can be sentient is a direct consequence of the reductionist materialist notion that consciousness is a byproduct of the complexity of the brain. If this idea is correct, then any sufficiently complex brain will be conscious, even a humanmade electronic brain. But I do not believe that it is correct. I remain firmly convinced of the “ghost in the machine,” model of consciousness. Consciousness is not a physical phenomenon—you cannot locate it, you cannot describe it, you cannot quantify it, and yet you know it exists because you experience it in yourself; in fact, you experience it as yourself. The brain does not produce consciousness; it acts more like a set of electronic relays or an old-fashioned telephone switchboard that connects consciousness (in some way that I admit I do not understand) to the physical world. This subject is too far off topic to discuss at any length here, but I will note that the claim that anything that science cannot investigate does not exist (consciousness, God, a higher sphere of reality). is not a scientific statement because it is not subject to falsification by means of the scientific method. It is, in fact, the position to which people who have a prior philosophical commitment to science as the only valid instrument for obtaining knowledge are forced to take. Faith in science as the only valid methodology for determining truth is an illustration of the old saying that, “To someone whose only tool is a hammer, every problem looks like a nail.” The scientific method is a remarkably effective tool for understanding and manipulating the physical universe, but it is useless for investigating questions about the non-physical universe, i.e. the universe of consciousness. A useful, and uncommonly clear, discussion of this topic takes place in chapter one of The Universe in a Single Atom by the Dalai Lama.


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