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Tell me about
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Popping into your mind
Consciousness is that annoying time between naps.
—Karin Gillespie[1]:111

Consciousness refers to the relationship between the mind and physical world. It is a complex system that includes memory, cognition, input from senses, and an awareness of selfhood. It is essentially the cognition of one's self, one's past, and one's potential futures at any given moment. The term "self-conscious" is often used to refer to acute self-awareness which results in feeling of unease in social settings and the fear of possible embarrassment.

We do not know why or even when consciousness evolved — that is, when living beings in the sequence you — your mother — your mother's mother — ... acquired first-person perspective. Most people intuit that on the one end of scale, (born) humans are conscious, and on the other, plants, jellyfish, or say a human hand is not; it is not known yet what to say on insects or fish fry, to name a few examples. This circumstance is of course a breeding ground for radicals of all sorts (and that's not even counting religious and New Age ideas) — from people who want bugs to have rights to total skeptics of animal consciousness. The former would imply that getting rid of lice is murder, and the latter, who include some fundamentalists (but also, in an agnostic form, the notable animal welfare researcher and Richard Dawkins's ex-wife Marian Dawkins[2]), would imply that chimpanzees are like eternal sleepwalkers on autopilot and can be slaughtered with a chainsaw without feeling anything. And needless to say, the question of fetal consciousness or unconsciousness generates a shitstorm of its own as well.

Scientific understanding[edit]

Despite consciousness being the central way in which human beings experience the universe, there are still many mysteries surrounding it. David Chalmers, Australian philosopher and professor, believes that while there are many "easy" issues about consciousness that can be addressed (how the brain stores memories, how attention works, how we organize ourselves, etc.), there is a difficulty in describing in a physical system what it is like to experience something such as a sight, texture, or even a feeling.[3] This problem, that we don't fully understand how a physical system gives rise to consciousness, has led to interesting propositions such as "it may be possible that even rocks are conscious."[Who?] According to bacterial geneticist James A. Shapiro[4] and biologist Lynn Margulis,[5] it is possible that some behaviors demonstrated by unicellular microorganisms, including bacteria, are indicative of them possessing consciousness, and it has been hypothesized in the scientific literature that a collection of signal-transducing proteins in some unicellular organisms that has come to be colloquially referred to as a nanobrain could play a key functional role, analagously to the nervous systems composed of neuronal cells present in some multicellular organisms.[6][7] The problem of how the physical neurobiology of the brain and various mental mechanisms gives rise to a seemingly unified consciousness is known as the "binding problemWikipedia" or "hard problem of consciousness."[8][9]

Science has attempted to discover if animals have consciousness, but without a language, and being able to posit questions "do you see yourself as an agent or merely an inevitable actor?" few scientists are willing to make claims one way or the other. Species more likely than others to have consciousness include the apes, whales/dolphins, some birds, and elephants.[10] Many philosophers, notably Descartes, insisted that humans are different from animals. However, this attitude has largely changed in the scientific community, and the question has shifted more to "how much consciousness do different species exhibit". The question "just which beings are sentient?" and views on it still remain (to put it mildly) controversial, but only a minority (and usually religious people) believe, like Descartes, that consciousness is unique to humans and all other animals like chimps or dogs are basically "natural zombies".

The scientific study of consciousness involves neuroscience, neurolinguistics, and psychology.

Philosophical understanding[edit]

Philosophers have looked at consciousness in quite different terms, identifying it less with some biological process that all biologically modern humans possess, but rather with the quest to identify the 'self' in philosophical terms.[citation needed] One argument, postulated by philosophers in the 70s, says that consciousness may have been different during the Homeric era from what it is today, since there are no writings of people talking about themselves as "unified internal subjects". In fact, philosophers such as Descartes and Locke were the first to really describe consciousness as we understand the concept today.

Philosophy, unlike science,[citation needed] allows for meta-consciousness — meaning "awareness of consciousness" or even "awareness of awareness." The American psychologist Julian Jaynes, in his seminal 1976 work The Origin of Consciousness in the Breakdown of the Bicameral Mind,[11] argued that early humans were not conscious, and consciousness evolved as recently as 3,000 years ago. Some critics[citation needed] of the book argued that what evolved was not consciousness itself but that literally mind-bending concept of meta-consciousness.

One complete mystery is when consciousness exists, and how and when it begins or ends. The problem is that consciousness is so far immeasurable, leading to major issues with Occam's razor and unfalsifiability. This leads to beliefs in things such as the soul, P-zombies, brain in a vat, and debates that can't be overstated on the issue of an afterlife or a lack thereof. Beliefs range wildly, from the belief that all matter in the universe is meta-conscious, to metaphysical solipsism. From the belief that consciousness(es) are eternal, lasting infinitely into the past and future, and cannot be created or destroyed, to the belief that a new consciousness is formed every time you wake up, and an old one destroyed every time you fall asleep.[note 1] Then there is the belief that consciousness doesn't exist at all, so there is nothing to be destroyed - for example, one idea is that consciousness exists only as a memory, very short or long term, since strictly speaking memory of conscious experiences is what one uses to talk about them, so maybe that's all there is and consciousness is reducible to memory formation. There are also attempts to use consciousness as an argument for God, but they are not very popular, for obvious reasons: if for the sake of argument we even assume existence of ghosts (like in some ancient nontheistic religions such as Jainism, which explicitly affirms eternity of the Universe), there is no way to prove that one of them is omnipotent!

Consciousness is also the most common objection given to the sci-fi idea of "mind-uploading" (or "hard" Artificial Intelligence): a computer program may simulate your preferences, habits, etc, but if it does not keep your first-person perspective, the argument goes, it is just that, a simulation, not you. This view falls prey to some serious arbitrariness challenges, however: for example, why does some very specific type of material (i.e. the material that comprises the human brain) produce consciousness but all/an arbitrary number of other types of matter do not? This question is in turn often answered by comparison with another extremely rare phenomenon - super low temperatures: as a matter of fact, temperatures below about 1 kelvin are only attested on Earth in a few special labs made by humans, and nowhere else in the known Universe (nor did they exist in the past)!

Even here, some common sense can be found, however. For example, a vast majority of people, regardless of ideological background, would easily agree with something like the following statement: "a man is sentient and a snowman isn't".


There is wide debate over which animals have consciousness, even in the absence of a clear definition of consciousness. There is also a more fringe debate over whether plants have consciousness. There is a long history of claims that only humans have consciousness, which has its roots in an Aristotelian or Cartesian concept of the soul as uniquely human; more recently, Daniel Dennett has argued that consciousness requires (human-like) language. Peter Carruthers argued that consciousness requires a theory of mind (the ability to conceptualise and think about one's thought processes), which limits it to humans and possibly chimpanzees, which seem to have a wide-ranging understanding of what other chimps perceive and think.[12]

Gordon Gallup promoted the mirror testWikipedia as an indicator of consciousness, where animals recognize their reflection in a mirror: this is true of humans, chimps, bonobos, and orangutans, although results in other species have been both proposed and contested. Others have used anatomical arguments based on brain structure to propose that consciousness is shared by mammals, and possibly reptiles and their descendants birds. Arnaud J. Cabanac identified a number of behaviors indicative of consciousness in mammals, reptiles, and birds but not other organisms, including the ability to make motivational trade-offs, take detours on routes, play, and express emotion. There are debates over broader vertebrates, arthropods, and molluscs; cephalopods in particular have evolved independently of mammals to have complex brains but it's not clear what is going on inside them.[12]

Fish have also passed the mirror test. Specifically cleaner wrasse.[13] Interestingly, the same study that found that cleaner wrasse passed the mirror test also criticizes the mirror test. The cleaner wrasse passed the test, but that does not not necessarily mean that the cleaner wrasse is now as cognitively complex as elephants, chimpanzees, or Eurasian magpies. All this test can tell us is that by the metrics of this test no difference can be told between a chimpanzee and a cleaner wrasse. After all, we can't tell the internal workings of the animal's mind when doing the test. We can't tell if, for example, the animal sees the spot, recognizes its significance, and just doesn't care to react to it.[13]

Criticisms can also be made of applying a test designed for the sensory experiences of humans and other primates and applying it to creatures that don't experience that same "sensory umwelt".[13]

Plants have been shown to respond to external stimuli. Because of that, some people suggest plants are conscious. Plants don't have brains, or even neurons (although there have been attempts to find equivalent structures). Some researchers claim to have found evidence of habituation or conditioning which would indicate a type of consciousness, although others caution that these experiments are preliminary and poorly-controlled and may have other explanations. Plant consciousness proponents cite the case of Mimosa pudica which normally curls up when dropped but after several drops ceases this behavior, suggesting it may be learning and changing its behavior in response to experience. Tests on peas claim to show Pavlovian classical conditioningWikipedia but lack proper experimental controls.[14][15] The mental powers required for classical conditioning are far below those identified in humans, great apes, or mammals and birds: classical conditioning has been studied in simple organisms like the sea slug Aplysia, and even in non-living material such as artificial substrates and conductors in an electric field.[16][17]

The argument that plants have feelings seems to be largely promoted by opponents of vegetarianism and veganism (Wikipedia quotes Timothy McVeigh as telling PETA that plants have feelings too, in a near-example of reductio ad Hitlerum.[18][19])

See also[edit]


  1. A Dollar Short: The Bottom Dollar Girls Go Hollywood by Karin Gillespie (2005) Thorndike Press. ISBN 0786280476.
  3. Facing Up to the Problem of Consciousness
  4. Shapiro, James (2006). Bacteria are small but not stupid: Cognition, natural genetic engineering, and sociobacteriology. Studies in History and Philosophy of Biological and Biomedical Sciences. 
  5. Margulis, Lynn (2001). The conscious cell.. Annals of the New York Academy of Sciences. 
  6. Webre, Daniel (2003). Bacterial chemotaxis. Cell. 
  7. Stock, Jeffry (2013). The biochemistry of memory. Current Biology. 
  8. Hard Problem of Consciousness, Scholarpedia
  9. Standord Encyclopedia of Philosophy: Consciousness
  10. [1]
  11. Jaynes, Julian (2000) [1976]. The origin of consciousness in the breakdown of the bicameral mind. Houghton Mifflin. ISBN 0-618-05707-2. 
  12. 12.0 12.1 Allen, Colin and Trestman, Michael, "Animal Consciousness", The Stanford Encyclopedia of Philosophy (Winter 2017 Edition), Edward N. Zalta (ed.).
  13. 13.0 13.1 13.2 Daley, Jason (February 11, 2019). "“Self-Aware” Fish Raise Questions About Animal Cognition". Sierra. 
  14. Plants Neither Possess nor Require Consciousness, Lincoln Taiz, Daniel Alkon, Andreas Draguhn, Chris Hawes, Gerhard Thiel, David G. Robinson, Trends in Plant Science, July 03, 2019, DOI:
  15. Plants don't think, they grow: The case against plant consciousness,, July 3, 2019
  16. Associative Learning in Invertebrates, Robert D. Hawkins and John H. Byrne, Cold Spring Harb Perspect Biol. 2015 May; 7(5): a021709. doi: 10.1101/cshperspect.a021709
  17. Experimental Evidence of Classical Conditioning and Microscopic Engrams in an Electroconductive Material, Nicolas Rouleau, Lukasz M. Karbowski, and Michael A. Persinger, PLoS One. 2016; 11(10): e0165269. Published online 2016 Oct 20. doi: 10.1371/journal.pone.0165269
  18. See the Wikipedia article on Plant rights. As at 07:07, 26 June 2019 in case someone edits this out.
  19. McVeigh to PeTA: "Where Do You Draw the Line?", FUR COMMISSION USA PRESS RELEASE, MAY 7, 2001, on


  1. Have fun sleeping tonight.