Updated: Apr 13
What, was he sad, or merry?
Like to the time o' the year between the extremes
Of hot and cold, he was nor sad nor merry.
-Shakespeare, Antony and Cleopatra
Semantic evidence shows that various types of simple excitement such as anger and sexual arousal correspond to higher brain temperature in animals, heat which must be accompanied by physical increases in brain fluidity, disorder and molecular motion. Such changes in the brain explain why, in angry and sexual contexts, we spontaneously make reference not only to heat but also fluidity, disorder and speed which doesn't actually exist in any way in the outside world, also how both the sender and receiver of such signals tend to understand them in a similar way, and why, oppositely, low excitement is often associated with lower temperature, solidness, order and stasis, both in the brain and in how we generally describe the experience of being less excited. We reference heat, fluidity, disorder and speed in order to be arousing. Our feelings are mutual about these qualities; we all agree about how and when they apply even though there's nothing consistently and outwardly hot, warm, cold, wet, dry, regular, random, fast or slow about the situations we apply them to. The qualities are sometimes perceivably present, but not reliably so, and not sufficiently to serve as a reasonable explanation for why we agree about them in such a universal manner. We consistently describe arguments as though there could be no doubt they relate closely to high thermal energy, but there's no actual heat to be observed outside the body. We insist, metaphorically, that arguments involve physical destruction, fluids like spit, blood and urine, speed, upwardness and outward motion which they do not. Meanwhile, resolving an argument is often described with words of nonexistent solidness, order, stillness, downwardness and contraction. We insist that excitement is like high temperature, wetness, splashing, floating, upwardness, and flying outward and that depression and boredom are the opposite by default with no rationale. The information we use to agree on these things comes from an inside source. Angriness, sexual desire and excitement are, to some extent, the same thing as brain heat, fluidity, disorder and motion. Boredom, disinterest and sleep are to some extent the same as brain coldness, solidness and stasis. When we have an exciting experience we apply to it the physical characteristics of an excited brain, and likewise for the less exciting. When we encounter things reminiscent of physical brain excitement in the outside world we feel excited, and apply to them in some degree the qualities from the more exciting mental category which they do not already exhibit. Finding something exciting is not the same as liking it. What we call beautiful tends to be a mixture of the more and less exciting.
Although it's been assumed that brain temperature is fixed within a tight range, it fluctuates rapidly by 3 or 4 degrees Celsius during normal behavior (Kiyatkin 2005). That the street drug ecstasy, or MDMA, which produces a feeling of euphoria in humans, causes a small but rapid and sustained increase in the temperature of the brain (Brown and Kiyatkin 2004), and a more rapid increase than that for muscle, is aligned with the concept of excitement relating to brain heat. The authors warn that the use of this drug coupled with exciting social interactions, or partying, especially at high ambient temperatures, can cause death by pushing brain temperature above its lethal limit, as was the fate of most of the most highly aroused rats in the experiment. Methamphetamine also produces a persistent temperature spike in the brain, greater than for body muscle, up to 4 degrees Celsius for up to 4 hours in rats (Brown et al. 2003). The authors found that methamphetamine combined with social interaction, which itself increases rat brain temperature by 1.5 degrees Celsius, can push the brain to its temperature limit of ~41 degrees Celsius and kill an animal. The way humans describe how such drugs make us feel also tells us that they heat the brain. We typically describe being high as hotter and more fluid, disorderly, dynamic, bright, upward and outward than being sober. Thus, to some extent, it seems possible to predict the thermal effects of drugs on the brain based on the way we characterize them linguistically.
Brains may handle information in somewhat the same way as a computer, but a brain is materially semi-dynamic and semi-disorderly, as a result of being semi-fluid, and therefore a computer, or a solid, static, metallic information system is not a good analogy. It’s long been known that brains vary in temperature, throughout the sleep-wake cycle for instance, but brain temperature has been considered more like a curious side effect of other brain functions, rather than an integral aspect of sensation, cognition and preferences. The brain is like a liquid crystalline thermometer rather than a computer. The physical condition of the matter making up a brain is flexible in a way that a computer is not. It’s capable of expansion and contraction and surviving periods of existence in conditions of more and less fluidity and solidness or higher and lower excitement. We describe our brains and minds as being flexible and variable with respect to temperature, fluidity, speed, brightness, regularity, straightness, vertical situation, color, length, size, and other things, and behave as though it makes perfect sense for us to do so. We say regularly, collectively and unaccountably of our brains or minds that they are blown, warped, buzzed, buzzing, bending, scattered, collected, light, bright, heavy, blank, dark, concentrated, torn, spinning, expanding, exploding, twisted or otherwise flexible in a physical sense. In a way that's similar to how we desire lower temperatures when we get too hot, desire heat when we get too cold, and feel satisfied with warmth, we find too much fluidity, disorder, speed or motion unpleasant and want to reduce the level of these things in our minds and environments, while also being displeased with extremities of solidness, order, slowness and stasis, which we feel a universal desire to disrupt.
Something universally similar about the brain is required to explain universal animal preferences such as those for complex mixtures of higher and lower pitch (e.g., song, music, language), bright and dark coloration, disorder and order (e.g., music, poetry, games), motion and stillness (e.g., dance) and fluidity and solidness (e.g., fountains, poems, paintings, idioms). Such mixtures are suspiciously brain-like, reminiscent of its complex liquid crystalline structure and comparable to the properties of a system situated at the point of transition between a liquid and crystalline phase.
Cocchi et al. (2017) describe a universal system of cognition in terms of complexity theory and phase transitions, and seem to suggest that brain randomness, order, fluidity, structure, and fast and slow flow play an extremely important role: “Chief amongst these is the notion of criticality, an umbrella term that denotes the behaviour of a system perched between order (such as slow, laminar fluid flow) and disorder such as the turbulence of a fast-flowing fluid, (Shih et al., 2015). A critical system shows scale-free fluctuations that stretch from the smallest to the largest scale, and which may spontaneously jump between different spatiotemporal patterns. Despite their apparent random nature, the fluctuations in these systems are highly structured, obeying deep physical principles that show commonality from one system to the other (so-called universality).”
They say also that psychological disorders probably correspond to physical transitions in the matter of the brain away from a state of mixed fluidity and order: “Conversely, brain disorders, as diverse as epilepsy, encephalopathy, bipolar disorder and schizophrenia may correspond to excursions from such an optimal critical point.”
The notion of simple phenomena like flow, order, disorder or speed governing our state of mind might remind one of the early philosophers holding the view, with great conviction, that in the apparently nonliving there is a certain, small amount of life. Rinne (1930) goes so far as to say that liquid crystallinity fills the gaps that seem to separate life from the nonliving:
"It is customary to draw the boundary between living organic and inorganic matter so that crystals represent the highest form of inorganic material and low organisms form the beginning of the organic world, with a definite and deep physiological gap between the two categories. In my opinion, this gap does not exist, since the sperms, which are undoubtedly living, are at the same time liquid crystals."
Esther Leslie (2016) points out the relationship between liquid crystallinity, language and art in Liquid Crystals: The Science and Art of a Fluid Form. She proposes a certain kind of psychological elasticity, asking: "What if a mode of thought were in intimate connection with phases of matter, which also emerge historically, or come to be known at historical moments? What if the hard form that is crystal, in periods of its prevalence, produced thought that is crystalline? What if an abundance of liquid made thought fluid, or if its absence made thinking desirous of fluidity to combat its parchedness?" Assuming it's true that thoughts of solidness invoke those of fluidity it's reasonable to suspect thoughts of things related to fluidity such as heat, disorder and motion invoke those related to solidness such as coldness, order and stasis, and that other perceptual extremities are similar. For instance brightness could generally cause animals to feel a desire for darkness, loudness could provoke in us a desire for silence, high-pitch for low-pitch, upwardness for downwardness, outwardness for inwardness, length for roundness, or roundness and containment could make us desire relatively exciting things like their opposites spikiness and freedom.
In the course of exploring the structure of language with respect to heat, fluidity, disorder, motion and their opposites it becomes clear that we treat other phenomena similarly, in that we tend to put them into more and less exciting categories and create alternating sequences of them for amusement. Several evidently exciting things, based on idioms, with links to examples, thus include at least heat (e.g., fire, the sun), fluidity (e.g., liquids, water, milk, tears, saliva, blood, smoke, air, clouds, flowing forms, long hair, long tails), disorder (e.g., destruction, breaking, cracking, strangeness, tilted-ness, asymmetry), dynamic motion (e.g., moving, running, spinning, racing, jumping), brightness (e.g., light, fire, the sun, redder and whiter colors), upwardness (up, above, the sky, heaven), outwardness (e.g., out, far, distant, outward body parts and motions), projections (e.g., spikiness, horns, hair, tails, lips, similar to outwardness), length (e.g., thin, tall, long lines, hair, tails, horns), higher-pitched sounds (e.g., screaming, whistling, whining, hissing, alarms, sirens, singing, treble), multiplicity (e.g., many things, copiousness, numerousness, abundance, large numbers, diversity, swarms, groups), extremities (e.g., hands, feet, wings, fins, the fringes, similar to outwardness and projections) and also various things we seem to have assigned an excitement level based on how they exhibit the qualities in question versus their opposites coldness (e.g., ice, frozenness, snow, ice cream), solidness (e.g., solids, stone, rocks, crystals, earth, diamonds, gems, bones, shells, horns, land, wood, glass, metal), order (e.g., straightness, flatness, simple shapes, roundness, symmetry), stasis (e.g., stillness, stoping, sleeping), darkness (e.g., no light, bluer and blacker colors), downwardness (e.g., down, below, underground), inwardness (e.g., in, near, home, the heart, mouths, penetration), entrances (e.g., holes, containers, mouths, doors, similar to inwardness), roundness (e.g., rounder objects, shortness, spheres, circles, points, balls, dots, heads, eyes, pupils), lower-pitched sounds (e.g., drums, thunder, bass), singularity (fewer things, one thing, small numbers, unity) and centrality (e.g. moderation, mediation, hearts, similar to inwardness). Many of the given high excitement qualities correspond to aposematic adaptations in animals and plants such as bright red, orange or yellow coloration, spikiness, safety in numbers and rapid movements while complex mixtures of more and less exciting things are more characteristic of animal bodies overall, sexual ornaments, flowers, songs and dances and other things under selection to be pleasing for animal sensory systems. According to Stevens and Ruxton (2012): "One of the most immediately apparent things when inspecting the range of warning signals in nature is just how common it is for them to be red, yellow and black." Bright fluidity appears to help certain horned lizard species that spray blood from their eyes defend themselves against canine and feline predators (Middendorf and Sherbrooke 1992). It's notable as well that in most of the cacti the plant itself is green but the spines are either red or white. From this perspective there's no need for aposematic coloration to be coupled with something actually deadly or harmful to a predator; brightness itself, as well as a pointy appearance, should provide a small level of protection.
In human language and behavior expressions of anger are often combinations of things from within the more exciting category (e.g., spitting is fluid and out, screaming is high-pitched, dynamic and disorderly) while expressions of negative arousal or sadness correspond to less excitement, and poetry is unexpectedly likely to be made up of sequences of alternating references to liquids and crystals, fluids and solids, destruction and order, movement and stillness, day and night, red and blue, flying and falling, leaving and returning and all imaginable indiscriminate mixtures of these and other more and less exciting things. As the qualities related in the category of higher excitement are increased in stimuli or added to expressions the result, on average, is more excitement for the perceiver. One can imagine, for instance, a long, flying, swirling, swarming, thronging, screaming, spiky, expanding, bright, red, yellow, shining, cracking, burning, spitting and unholy phenomenon having an essence of excitement greater than that of a singular, round, solid, dark, shrunken and silent object lying motionless in the bottom of a hole. Animals recognize each other as something in between, and prefer to be stimulated by mixtures of opposites rather than combinations of categorically related stimuli. We prefer, for example, to experience lower-excitement downwardness in a mixture with exciting, higher-pitched sounds, disorder, fluidity, and/or dynamic motion, and would rather not experience high-pitch in combination with an elevated vertical position, disorder, fluidity and/or dynamic motion. We would rather experience an object with a dark upper section and a bright lower section than the other way around, and motion mixed with darkness instead of brightness. We like a sphere to be decorated with higher-excitement phenomena, same with entrances, and find stimuli with more than one (but not too many) spherical features or entrances intriguing. We find lines more exciting than circles and often prefer for the rounder parts of a thing to be located above the linear ones. That the opposite arrangement is more exciting is evident most simply in the exclamation point (!). But it can also be seen, in a subtle way, in the expression "hand over fist," meaning very fast, the expression "raising eyebrows," meaning causing some excitement, probably also the way we tend to narrow our mouths, squint our eyes and form the face to be generally pointier when were "cross." Faces of approval, by comparison, appear to involve subtle curves and roundness. Animals rearrange their bodies to display more exciting features at higher positions when they intend to be unpleasant, and do the opposite when they intend to be pleasant. We move the lower and central portions of our bodies dynamically and semi-chaotically when we intend to be pleasant and attract a mate or be friendly but move the upper portion and extremities dynamically and chaotically to be unpleasant, indicating that the former (apparently universal elements of dancing), a representative of a complexity effect, specifically disorder—down/order—up, coupled to a seemingly irreducible sensory bias favoring such mixtures, is more appealing but less exciting than the later, such as flailing.
Other evidence for mental categories can be seen in how roughly synonymous words for qualities within a category can often be exchanged in expressions without significantly altering the overall meaning. Words we use for order, both simple geometric order and social order, are often also used to express agreement. The orderly words “even,” “straight,” “level,” “correct,” “rectify,” “right,” “alright,” “square,” “just” and “true” are all ways to say we agree, and so are the words “solid,” “down,” “tight,” “contract,” “dig it” and “I'm in.” Words we use for humor (from the Latin word for moisture) often refer to disorder (for example “wisecrack,” “broke as a joke,” “dirty joke”) but also other qualities from the hotter category such as heat, speed, up and out, like in “on fire,” “quick wit,” “running joke,” “bust up,” “crack up,” “uproarious” and “break out into laughter.”
There are patterns in the way we refer to animals, in artistic expressions and otherwise, showing we collectively consider them to be more exciting than inanimate, solid objects, and some to be more exciting than others. Cats, dogs, birds and snakes, for instance, are more common in references to sex and anger, and probably more likely to be found in containers in idiom, art, and myth than animals widely considered less exciting like pigs and cows. Moderation and intrigue can seemingly be created in stories and expressions by contradictions involving mixtures of more and less exciting animals, such as pigs and a wolf, or a pig and a spider, less exciting animals in more exciting circumstances, such as a cow jumping over the moon, or more exciting animals in less exciting circumstances such a cat or a rabbit in a bag or a hat.
We make a distinction between certain body parts and others, apparently on the basis of length versus roundness, outward versus inwardness, and the amount of motion we perceive them to undergo during interactions. Relatively long, outward, flowing and dynamic body parts like fingers, hands, legs and feet are treated as more exciting than the rounder, more static and central parts of the body, while necks, crevices and holes we treat as unexciting and in need of decoration or disruption. Thus in humans the longest finger is more provocative than the thumb, and long hair is more exciting and provocative than short hair and long horns, tails and feathers are associated with sex throughout the animal world. Our use of the expression "the bird" for flipping someone off is an indication of the fact the we find length and birds exciting, but also flipping. Disorderly overlapping finger arrangements are used as gang signs, while shaking a hand with the two shortest fingers extended is a friendly, fun signal, and a static round fist implies comradery, from all of which it can be seen that we find length more exciting than roundness. Aristotle explained hair and length as a consequence of heat and fluidity in the brain:
“No animal has so much hair on the head as man. This, in the first place, is the necessary result of the fluid character of his brain, and of the presence of so many sutures in his skull. For wherever there is the most fluid and the most heat, there also must necessarily occur the greatest outgrowth” (Aristotle and Ogle 1882).
Aristotle saw ornamental body hair in humans as being related to fluidity because it has a fluid-like appearance, and to heat because we relate fluidity to heat and excitement by default, psychological realities which themselves appear to be the cause of long, flowing ornaments evolving in Animals throughout the Kingdom. Animals choose to mate with others of their kind who exhibit exciting features as a sort of compensation for what we all perceive as less exciting roundness and inwardness, so that round parts, like the top of the head, and crevices and holes in the body like armpits, mouths and genitals are adorned with flowing hair, tails and an assortment of other protuberances in numerous insects, fish, reptiles, birds and mammals with no respect for taxonomic boundaries. Such ornaments evolve to exploit universal preferences that arise from the special, liquid crystalline physical situation of the brain, within constraints imposed by differential survival and other processes. The decorations themselves are not what animals find likable, but the contradiction, complexity and familiarity they create together overall.
Importantly, the unexciting, disruption-inciting appearance of roundness and inwardness can be compensated for by any of the more exciting qualities, not only those that are perceivable as opposite outside the brain. Inward body parts can be made more exciting by protrusion, a perceivable contradiction in that in and outwardness are observable opposites, but length, flowing forms and/or brightness can be substituted for protrusion to achieve the same result of likable moderation. This tells us, incidentally, that our appreciation for the contradiction out—in itself, although it's perceivable, was not entirely acquired by observation. Length, fluidity and brightness are understood in the brain to be opposites of inwardness just as legitimate as in versus out even though they can’t be observed externally as such. Any exciting quality can be substituted for any other exciting one as an interesting contradiction to any less exciting quality, resulting in a set of mixtures all of which can be observed at higher than expected rates in all types of phenomena under aesthetic selection as well as some which are not such as hallucinations and dreams.
Aristotle, and William Ogle. Aristotle on the Parts of Animals. Translated, with Introduction and Notes, by W. Ogle. Kegan Paul & Co, 1882. Brown, P. Leon, and Eugene A. Kiyatkin. "Brain hyperthermia induced by MDMA (‘ecstasy’): modulation by environmental conditions." European Journal of Neuroscience 20.1 (2004): 51-58. Cocchi, Luca, et al. "Criticality in the brain: A synthesis of neurobiology, models and cognition." Progress in neurobiology 158 (2017): 132-152. Kiyatkin, Eugene A. "Brain hyperthermia as physiological and pathological phenomena." Brain research reviews 50.1 (2005): 27-56. Leslie, Esther. Liquid Crystals: The Science and Art of a Fluid Form. Reaktion Books, 2016.
Middendorf III, George A., and Wade C. Sherbrooke. "Canid elicitation of blood-squirting in a horned lizard (Phrynosoma cornutum)." Copeia (1992): 519-527.
Rinne, F. "Sperms as living liquid crystals." Nature 126.3173 (1930): 279-279.
Shih, Hong-Yan, Tsung-Lin Hsieh, and Nigel Goldenfeld. "Ecological collapse and the emergence of travelling waves at the onset of shear turbulence." Nature Physics 12.3 (2016): 245-248.
Stevens, Martin, and Graeme D. Ruxton. "Linking the evolution and form of warning coloration in nature." Proceedings of the Royal Society B: Biological Sciences 279.1728 (2012): 417-426.