qualia

In philosophy."qualia" refers to the subjective qualities of our experience,
what it's like for Alice to see blue, or for Bob to be delighted.
Qualia are the ways things seem to us.
(What Is Math's Mysterious Langlands Program Really About? Natalie Wolchover at Quanta Magazine)

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Qualia Wikipedia

...C.S. Peirce introduced the term quale in philosophy in 1866, and in 1929 C. I. Lewis was the first to use the term "qualia" in its generally agreed-upon modern sense.

...There are recognizable qualitative characters of the given, which may be repeated in different experiences, and are thus a sort of universals; I call these "qualia." But although such qualia are universals, in the sense of being recognized from one to another experience, they must be distinguished from the properties of objects. Confusion of these two is characteristic of many historical conceptions, as well as of current essence-theories. The quale is directly intuited, given, and is not the subject of any possible error because it is purely subjective.

...Daniel Dennett suggested that qualia was "an unfamiliar term for something that could not be more familiar to each of us: the ways things seem to us".[8] He identifies four properties that are commonly ascribed to qualia.[8] According to these, qualia are:

• ineffable — they cannot be communicated, or apprehended by any means other than direct experience.
• intrinsic — they are non-relational properties, which do not change depending on the experience's relation to other things.
• private — all interpersonal comparisons of qualia are systematically impossible.
• directly or immediately apprehensible by consciousness — to experience a quale is to know one experiences a quale, and to know all there is to know about that quale.

...Another way of defining qualia is as "raw feels". A raw feel is a perception in and of itself, considered entirely in isolation from any effect it might have on behavior and behavioral disposition.[10] In contrast, a cooked feel is that perception seen in terms of its effects. For example, the perception of the taste of wine is an ineffable, raw feel, while the behavioral reaction one has to the warmth or bitterness caused by that taste of wine would be a cooked feel. Cooked feels are not qualia.

...American philosopher Thomas Nagel's paper What Is it Like to Be a Bat?[21] is often cited in debates about qualia, though it does not use the word "qualia". Nagel argues that consciousness has an essentially subjective character, a what-it-is-like aspect. He states that "an organism has conscious mental states if and only if there is something that it is like to be that organism — something it is like for the organism."

...Vilayanur S. Ramachandran and William Hirstein[49] proposed three laws of qualia (with a fourth later added), which are "functional criteria that need to be fulfilled in order for certain neural events to be associated with qualia" by philosophers of the mind:

• Qualia are irrevocable and indubitable. You don't say 'maybe it is red but I can visualize it as green if I want to'. An explicit neural representation of red is created that invariably and automatically 'reports' this to higher brain centres.
• Once the representation is created, what can be done with it is open-ended. You have the luxury of choice, e.g., if you have the percept of an apple you can use it to tempt Adam, to keep the doctor away, bake a pie, or just to eat. Even though the representation at the input level is immutable and automatic, the output is potentially infinite. This isn't true for, say, a spinal reflex arc where the output is also inevitable and automatic. Indeed, a paraplegic can even have an erection and ejaculate without an orgasm.
• Short-term memory. The input invariably creates a representation that persists in short-term memory – long enough to allow time for choice of output. Without this component, again, you get just a reflex arc.
• Attention. Qualia and attention are closely linked. You need attention to fulfill criterion number two; to choose. A study of circuits involved in attention, therefore, will shed much light on the riddle of qualia.[

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Instances I've quoted in various hypertext documents:

..the hypothesis I am postulating here is the following: consciousness is a non-local field phenomenon not caused by, nor reducible to, the brain, but simply associated in some manner with the brain. All understanding and knowledge ever registered by a conscious entity survives ad infinitum in the field of consciousness as permanent experiences, or qualia. Therefore, all universal knowledge is, in principle, accessible by any conscious entity. It is the local attention filters of the nervous system, evolved as a consequence of earlier survival advantages, which prevent us from accessing this universal repository of knowledge. But through perturbations of ordinary brain operation, which partially and temporarily disable or bypass some of these filters, one can gain awareness of it.
(Bernardo Kastrup Dreamed Up Reality)

...Panpsychism offers resolutions to mind-body problems that dualism and materialism find intractable. Present-day philosophy of mind is dominated by materialist theories that cannot adequately address issues of consciousness, qualia, or the emergence of mind in the universe.
(David Skrbina Panpsychism in the West)

...To begin making sense of what consciousness is, you have to specify what you are asking. AI pioneer Marvin Minsky called consciousness "a suitcase term", meaning that people toss in whatever they wish, so that it becomes swollen with related but confounding concepts like perception, attention, wakefulness, memory, emotion and intelligence. I mean none of these. By consciousness, I mean "phenomenal consciousness": your what-it's-like inner sense; your private feelings. It is the sight of your newborn daughter, swaddled; the sound of Mahler's Symphony No. 2; the smell of garlic cooking in olive oil. These interior experiences are called "qualia", and they are the crux of the conundrum.
(Robert Lawrence Kuhn at New Scientist 22x25)

...No one knows how electrochemical changes in the brain become sights, sounds, flavors, odors, textures, and the rest of what we see and feel. Those qualia somehow exist and are perceived, but no one knows where they are located, what perceives them, how they are perceived, or what they really are. No one knows the wellsprings of feelings, thoughts, emotions, and memories either.
(Robert Saltzman The Ten Thousand Things)

......What you just experienced — the strawberry-ness of strawberry, the red-ness of red — these are qualia. They're the felt qualities of consciousness, the subjective textures that make experience more than just information processing. They're what makes you you rather than a very sophisticated computer.

Scientists can tell us everything about strawberries. They can map the exact molecules that trigger your taste buds, trace the neural pathways that fire in your brain, even predict your facial expressions when you taste something sweet. But there's one thing they can't capture: what it actually feels like to experience that sweetness.

This is the famous "hard problem of consciousness." We can explain all the mechanics of how a brain processes information, but we can't explain why there's something it's like to be conscious. Why isn't it all just happening in the dark, with no inner experience at all?
(Oguz Birinci at Medium

...Something beyond our understanding occurs in the genesis of qualia, the transformation of an objective cerebral computation to a subjective experience. Philosophers argue endlessly over how these transformations occur, and whether we will ever be capable of understanding them. Neuroscientists, by and large, are content for the moment to accept that they do occur, and to devote themselves to finding the underlying basis or "neural correlates" of consciousness, starting from such elemental forms of consciousness as the perception of motion.
(Oliver Sacks at NYRB, 15i04)