- are those sensations real
- are they things in their own right?
- It seems contradictory to think that the physical world actually contains sensations
- do philosophers have a name for it?
Descartes distinguished between extensible phenomena which take up space, and inextensible phenomena, in minds. The reconciliation of Maxwell's demon with increasing entropy, information has intrinsic energy consequences. Modern physics is reversing the idea that information is a secondary property of matter, and picturing information flow as fundamental, or as the unifying framework or language: with Wheeler's 'It from bit' doctrine and digital physics, and approaches like Loop Quantum Gravity that try to synch up relativity with quantum mechanics by picturing space and time as emerging from an information layer, a spin quantum network.
Another sense it might not be 'real' is it being subjective. If no one else can be sure if an event caused you pain, or you are acting, is the distinction in the world, or entirely private? This relates to issues of solipsism and 'philosophical zombies': whether other people appearing to have similar experiences to our own is really solid evidence that they do. Behaviourism grew out of the Logical Positivism of the Vienna Circle, and sought to shift away from 'unknowable' inner experiences to observing behaviour only, as being the domain of 'proper science'. That led to a lot of problems in practice, inhuman experiemnts, bad results, and huge limits on what could be researched. Philosophically, Behaviorism was really blown out of the water by Wittgenstein's later work which gave us the Private Language Argument. He argues through his 'beetle in a box' that sensatiinsmlike pain, we understand through many cross-references with others, that he calls language games, and our inner world is crucially made coherent & able to be put into narrative groups by these. The bigger picture of this is to see the idea of a single 'objective' reality as faulty, because no one experiences that, instead there is intersubjectivity, a kind of composite cross-referencing of experiences, where we project ourselves into other minds, and communicate by inviting others to project into ours.
Douglas Hoffman argues we can't rely on our evolved senses to show us what is 'real', though. We didn't evolve our senses for that, and it often acts against the interests of our genes for our senses to do so. There is evidence people with depression see some phenomena more accurately than optimists, but optimists are typically more likely to pass on their genes (until we destroy the biosphere with a climate war-induced nuclear winter because we thought it would all 'just work out somehow', anyway - optimism can definitely go too far, or be misused). I would say Hoffman isn't pointing at how to see what's 'real', but how we can use tools and tactics to correct for cognitive biases and blindspots, and use a mixture of ways of knowing similarly to how we use multiple senses to achieve 'concilience' vrom their combined picture - optical and sensory illusions help us see how this happens, and conflicts between senses make us pay much closer attention to any anomolies, like social disagreements make us argue out the disagreement to find consensus. We build our own reality from our reconciling experiences, Anil Seth has a nice example of how cues help us process noises as speech. Then together through social contention (eg Trump supporters vs everyone else), and science tools like controlled trials, to define our consensus reality.
Qualia is the term for what about a sensatiin is experienced specifically from a point of view, within a personal context. Nagel argued we can't 'truly' know what it's like to be a bat, even by scanning it's brain or simulating echo location, or any other method. I would look at how we learn a foreign language, and can gain different degrees of fluency, then apply that to learning dolphin language (tbought to involve 'sonic holograms' or 3D pictures): we could maximise that by sharing modes of life, a human living as a dolphin, a dolphin somehow living like a human, talking about it & sharing experiences & cultural context. But, there could be limits on intersubjectivity from having different brains, though we could use mental tools to address that, like 'horse whisperers' or others try to kind of 'method act' into being like the animal enough to 'get' them.
In Buddhist thought they have this term 'ayatana', usually translated as 'sense base'. From it or in it, the sense and the sense-domain arise mutually, in a pair. Seeing and the visual world, hearing and the auditory world ir domain, etc. It's an interesting approach because it sees experiences of the internal & external as mutually arising, which we also see from the specialisation of the brain's hemispheres as understood from split brain patient research, there's a dynamic quality of sharpening the sense with informatiin from the world, and refining the picture of the world from the sense. It also nicely expands to other animals, which will see other layers of reality, but in the wider Buddhist picture all sentient beings are considered to have a kind of universal intersubjectivity forunded in awareness or presence-in-the-moment that we build out' from, and because of that we can in principle 'see in' to those world-structures of others and construct that intersubjectity.
1) Yes, sensations involve information, which has reality
2) Sensations are conceptualised and contextualised by social experience, within language games which help us to build intersubjectivity, the ability to 'see in' to the experiences of others
3) Limits from evolution and both conscious and unconscious deception place limits on how sure we can be about the sensations of others & ourselves but as above these are not fundamental limits, and we use methodologies to increase how sure we can be about whether our own sensations and those of others usefully correspond with the world, but that will be by degree rather than absolute - it's problematic to say 'real' when what we mean fundamentally is, useful: within some language game or framing set of personal and social assumptions/context, and if we disagree on what those are, we may find ourselves in different realities.
4) Specialised terms in philosophy that go beyond ordinary language about sensory information and how to understand it, include qualia and ayatana.