Abstract
Sentient beings are capable of having pleasant or unpleasant experiences and therefore have interests, which I assume to be necessary and sufficient for moral status. But which animals are sentient? While sentience is sufficient for having interests, maybe it is not necessary. Perhaps some creatures are conscious—having subjective experience—yet are not sentient because their consciousness contains nothing pleasant or unpleasant. If so, do they nevertheless have interests and moral status? This chapter addresses both questions. After identifying several methodological assumptions, it proceeds to consider the state of the evidence for sentience in mammals and birds, reptiles, amphibians, fish, cephalopods, and arthropods (in particular, crustaceans and insects). It then takes up the possibility that insects are conscious yet not sentient. In exploring the mental life of insects, the discussion considers the possibility of robots who are conscious but not sentient, eliciting implications for moral status.
This is a preview of subscription content, log in via an institution to check access.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Notes
- 1.
Roughly this definition may be found in various sources. See, e.g., [1].
- 2.
This qualification is motivated by the possibility that consciousness and particular conscious states such as pain have no selective advantage over their unconscious , similarly information-processing counterparts.
- 3.
My approach may be inconsistent with classic foundationalism, since I help myself to knowledge of species membership and of the hardware in other people’s heads when I haven’t looked inside. For the record, I regard classical foundationalism as a time-dishonored approach to epistemology that leads, uselessly, to global skepticism . My approach to epistemology is consistent with both coherentism and moderate foundationalism.
- 4.
There is reason to believe that some human beings, despite being born without a cortex, nevertheless have conscious experiences [2]. If so, perhaps their experiences include pain, in which case there would be some exceptions to the rule that human pain requires cortical processing.
- 5.
Gary Varner [3] influentially presented a table of types of evidence for sentience. The types of evidence he catalogues overlap with my list of six criteria. I prefer my list because it combines several of his neurological criteria concisely into “a central nervous system with a (suitable) brain” and offers considerably more specificity regarding behavioral criteria.
- 6.
It is worth noting that these two systems are unlikely to be entirely discrete.
- 7.
The cited article is also illuminating about some of birds’ more impressive intellectual feats, as discussed in the next paragraph.
- 8.
- 9.
The two examples that follow involve corvids and tits. The examples presented by Gunturkun and Bugnyar [15] involve corvids and parrots. So the claim that impressive intellectual feats bolster the case for sentience might apply only to corvids, tits, and parrots.
- 10.
For a helpful review of the scientific literature on these topics, see [20].
- 11.
Colin Allen makes this point persuasively; see (p. 26 in [27]).
- 12.
Many people who reflect on octopuses’ mental lives have wondered what it is like to be an octopus. I suggest an additional question: What, if anything, is it like to be an octopus tentacle?
- 13.
For a discussion of ambiguous evidence, see della Roca et al. (p. 79 in [36]).
- 14.
One especially noteworthy aspect of insect behavior is an apparent lack of protective behavior toward injured body parts [40].
- 15.
Although Tye believes bees may not experience pain, he argues that they experience fear and perhaps anxiety [9]—unpleasant feelings that would entail that bees are sentient after all. So Tye would not accept the present supposition.
References
IASP terminology. International Association for the Study of Pain; 2017. http://www.iasppain.org/Education/Content.aspx?ItemNumber=1698#Pain. Accessed 20 Dec 2018
Merker B. Consciousness without a cerebral cortex: a challenge for neuroscience and medicine. Behav Brain Sci. 2007;30(1):63–81.
Varner GE. Nature’s interests? New York: Oxford University Press; 1998.
Hardcastle V. The myth of pain. Cambridge, MA: MIT Press; 1999.
Seth AK, Baars BJ, Edelman DB. Criteria for consciousness in humans and other mammals. Conscious Cogn. 2005;14(1):119–39.
Shriver A. Minding mammals. Philos Psychol. 2006;19(4):433–42.
Medina L, Reiner A. Do birds possess homologues of mammalian primary visual, somatosensory, and motor cortices? Trends Neurosci. 2000;23(1):1–12.
Edelman DB, Baars BJ, Seth AK. Identifying hallmarks of consciousness in non-mammalian species. Conscious Cogn. 2005;14(1):169–87.
Tye M. Tense bees and shell-shocked crabs: are animals conscious? New York: Oxford University Press; 2016.
Dugas-Ford J, Rowell JJ, Ragsdale CW. Cell-type homologies and the origins of the neocortex. Proc Natl Acad Sci U S A. 2012;109(41):16974–9.
Smith J, Boyd K. Lives in the balance: the ethics of using animals in biomedical research. Oxford: Oxford University Press; 1991.
Gentle MJ, Hunter L, Waddington D. The onset of pain related behaviours following partial beak amputation in the chicken. Neurosci Lett. 1991;128(1):113–6.
Gentle MJ, Corr SA. Endogenous analgesia in the chicken. Neurosci Lett. 1995;201(3):211–4.
Shettleworth S. The role of novelty in learned avoidance of unpalatable ‘prey’ by domestic chicks (Gallus gallus). Anim Behav. 1972;20(1):29–35.
Güntürkün O, Bugnyar T. Cognition without cortex. Trends Cog Sci. 2016;20(4):291–303.
Hunt GR. Manufacture and use of hook-tools by new Caledonian crows. Nature. 1996;279(6562):249–51.
Godfrey-Smith P. Other minds. New York: Farrer, Straus and Giroux; 2016.
Clayton NS, Dickinson A. Episodic-like memory during cache recovery by scrub jays. Nature. 2001;395(6699):272–4.
Sherry D, Duff S. Behavioural and neural bases of orientation in food-storing birds. J Exp Biol. 1996;199(1):165–72.
Mosley C. Pain and nociception in reptiles. Vet Clin North Am. 2011;14(1):45–60.
Cabanac M, Cabanac AJ, Parent A. The emergence of consciousness in phylogeny. Behav Brain Res. 2009;198(2):267–72.
Paradis S, Cabanac M. Flavor aversion learning induced by lithium chloride in reptiles but not in amphibians. Behav Process. 2004;67(1):11–8.
Ingle D. Two visual systems in the frog. Science. 1973;181(4104):1053–5.
Machin KL. Fish, amphibian, and reptile analgesia. Vet Clin North Am Exot Anim Pract. 2001;4(1):19–33.
Stevens CW. Opioid research in amphibians: an alternative pain model yielding insights on the evolution of opioid receptors. Brain Res Rev. 2004;46(2):204–15.
Smith ES, Lewin GR. Nociceptors: a phylogenetic view. J Comp Physiol A. 2009;195(12):1089–106.
Allen C. Fish cognition and consciousness. J Agric Environ Ethics. 2013;26(1):25–39.
Sneddon LU. Evolution of nociception in vertebrates: comparative analysis of lower vertebrates. Brain Res Rev. 2004;46(2):123–30.
Dreborg S, Sundström G, Larsson TA, Larhammar D. Evolution of vertebrate opioid receptors. Proc Natl Acad Sci U S A. 2008;105(40):15487–92.
Sneddon LU. The evidence for pain in fish: the use of morphine as an analgesic. Appl Anim Behav Sci. 2003;83(2):153–62.
Millsopp S, Laming P. Trade-offs between feeding and shock avoidance in goldfish. Appl Anim Behav Sci. 2008;113(1–3):247–54.
Rose JD. The neurobehavioral nature of fishes and the question of awareness and pain. Rev Fish Sci. 2002;10(1):1–38.
Chandroo KP, Yue S, Moccia RD. An evaluation of current perspectives on consciousness and pain in fishes. Fish Fish. 2004;5(4):281–95.
Ito H, Yamamoto N. Non-laminar cerebral cortex in teleost fishes? Biol Lett. 2008;5(1):117–21.
Smith JA. A question of pain in invertebrates. ILAR J. 1991;33(1–2):25–31.
Della Rocca G, Di Salvo A, Giannettoni G, Goldberg ME. Pain and suffering in invertebrates: an insight on cephalopods. Am J Anim Vet Sci. 2015;10(2):77–84.
Elwood RW. Pain and suffering in invertebrates? ILAR J. 2011;52(2):175–84.
Stefano GB, Cadet P, Zhu W, Rialas CM, Mantione K, Benz D, et al. The blueprint for stress can be found in invertebrates. Neuro Endocrinol Lett. 2002;23(2):85–93.
Sneddon LU. Pain in aquatic animals. J Exp Biol. 2015;218(7):967–76.
Eisemann CH, Jorgensen WK, Merritt DJ, Rice MJ, Cribb BW, Webb PD, et al. Do insects feel pain?—A biological view. Cell Mol Life Sci. 1984;40(2):164–7.
Barron AB, Klein C. What insects can tell us about the origins of consciousness. Proc Natl Acad Sci U S A. 2016;113(18):4900–8.
Disclaimer and Acknowledgments
This work was supported, in part, by funds from the National Institutes of Health (NIH) Clinical Center. The views expressed here are the author’s own and do not reflect the position or policy of NIH or any other part of the federal government. The author would like to thank Syd Johnson, Adam Shriver, Andrew Fenton, colleagues in the Department of Philosophy, George Washington University, and attendees of a talk at the 2018 Rocky Mountain Ethics Congress at the University of Colorado-Boulder for feedback on a draft.
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2020 This is a U.S. government work and not under copyright protection in the U.S.; foreign copyright protection may apply
About this chapter
Cite this chapter
DeGrazia, D. (2020). Sentience and Consciousness as Bases for Attributing Interests and Moral Status: Considering the Evidence and Speculating Slightly Beyond. In: Johnson, L., Fenton, A., Shriver, A. (eds) Neuroethics and Nonhuman Animals. Advances in Neuroethics. Springer, Cham. https://doi.org/10.1007/978-3-030-31011-0_2
Download citation
DOI: https://doi.org/10.1007/978-3-030-31011-0_2
Published:
Publisher Name: Springer, Cham
Print ISBN: 978-3-030-31010-3
Online ISBN: 978-3-030-31011-0
eBook Packages: MedicineMedicine (R0)