The point is that it doesn't matter whether these hypothesis are correct or not. The only thing that worries me is how the touch happens if in the real world it is the interaction of atoms (in particular, electrons). thanks

  • Rather than the atoms interacting, in the simulation the "electrons" that transmit the signal are directly manipulated.
    – christo183
    Nov 17, 2020 at 10:32
  • that is, the touch will still occur?
    – Android
    Nov 17, 2020 at 10:36
  • 2
    It would happen exactly in the same way as it happens in dreams, that is as a touch hallucination. Nov 17, 2020 at 12:32
  • can we call it touch?
    – Android
    Nov 17, 2020 at 13:19
  • 1
    Only the sensation of touch occurs.
    – christo183
    Nov 17, 2020 at 14:24

4 Answers 4


Your main worries can be explained away by the contemporary extreme materialism school of psychology called Eliminative materialism which rejects the existence of certain qualia or certain types of mental states that most people believe in, and thus avoids the usual reductive physicalism's disjunction problem which results in the indeterminacy of propositional content. In summary, under this view, certain mental states such as your touch sensation don't exist at all, just an epiphenomenon of brain function with its corresponding neural process under certain additional environmental requirement such as a living skull. In this sense, you don't even necessarily need a hand to get a feeling of touch, touch "occurs" to you as a mere illusion inside your brain while maybe in the real world it is the interaction of atoms.

Eliminative materialism is the relatively new (1960s–1970s) idea that certain classes of mental entities that common sense takes for granted, such as beliefs, desires, and the subjective sensation of pain, do not exist. The most common versions are eliminativism about propositional attitudes, as expressed by Paul and Patricia Churchland, and eliminativism about qualia (subjective interpretations about particular instances of subjective experience), as expressed by Daniel Dennett and Georges Rey. These philosophers often appeal to an introspection illusion.

In the context of materialist understandings of psychology, eliminativism stands in opposition to reductive materialism which argues that mental states as conventionally understood do exist, and that they directly correspond to the physical state of the nervous system... Some eliminativists, such as Frank Jackson, claim that consciousness does not exist except as an epiphenomenon of brain function; others, such as Georges Rey, claim that the concept will eventually be eliminated as neuroscience progresses.

If you find above view is too radical, your main worries can also be explained away by Property dualism which views that non-physical, mental properties (such as touch, thoughts) exist in, or naturally supervene upon physical substances such as brain.

Non-reductive physicalism is the predominant contemporary form of property dualism according to which mental properties are mapped to neurobiological properties, but are not reducible to them. Non-reductive physicalism asserts that mind is not ontologically reducible to matter, in that an ontological distinction lies in the differences between the properties of mind and matter. It asserts that while mental states are physical in that they are caused by physical states, they are not ontologically reducible to physical states.


What you know is something. What you know is the subjective impression of the sensation of touch, for example the sensation that what appears subjectively to you to be your fingers are touching what appears subjectively to you to be a book.

What you believe is something else. What you believe is that touching is occurring in the material world, for example that your fingers are touching the hard cover of a book.

What you know is definitely something you know. As such, it is as real as could be, though possibly somewhat misleading. Still, at least you know something.

Whether what you believe is true, you don't know, but you believe it, which seems good enough. If you are still alive, it is probably good enough.

Obviously, if your are a brain in a vat, what you believe about the material world, if anything, will be likely false, but bear in mind that if you are not any brain in a vat, what you believe about the material world would be also most plausibly false. Again, what matters is that you should be alive and feeling good (If not, sorry for that).

Now, if I myself only existed as part of a simulation, I fail to see how the subjective impression I have now that my fingers are touching the keys on my computer keyboard could possibly be simulated. The simulation of a subjective impression is not itself a subjective impression, and yet I do have subjective impressions. This seems to exclude the possibility of any sort of simulation, unless we equivocate on the word "simulation".

So, brain in a vat, why not, though not even remotely plausible, but a simulation, no.


There are some principles of touch that are not so evident.

a) All solids, even those that seem absolutely rigid like glass or diamond, act like a beach ball during the kick in the proximity of another body: they get deformed. They start by compressing in the touch zone, then, the potential energy stored comes back and produces rejection in the other object, while the affected object recovers its form. A theoretically perfectly rigid object would need of infinite atomic forces within to keep integrity, otherwise it would break with the single interaction of an electron.

b) What happens in such case is that atoms, "trying" to keep an ordered position on the solid grid, get closer. That is like pushing a string: it tends to get to its original position. The opposite case, trying to break an object by pulling on opposite sides is similar: atoms get distant, and they "try" to get closer again, like pulling a string. The more you pull or push, the larger the force, of course, until the spring breaks.

c) Notice the usage of the word "trying": it is only didactic. Atoms have no will, but they show spatial tendencies, to remain in a place or to move, according to natural laws, starting from fundamental interactions.

d) Atoms are not small balls. Every possible thing in the universe (including matter) can be understood as energy. So, solids, touch, movement, etc, it's all about energy lumps interacting.

e) The nature of energy is not scientifically clear. We have mathematical ways to describe its behavior, but what it is, is a mystery.

f) Touch does not occur at an atomic or molecular level. Touch occurs in the mind. Atomically, the interactions are always the same, as described in the atomic/quantum mechanics theory.

When you think of atoms, assess atomic interactions. When you think of molecules, assess molecular interactions. When you think of solids, assess solids interaction. It is not logical to assess the interaction between an atom and a solid, or within a concept and a molecule, or within a car and an electron.

That's the issue with the question: you are trying to relate a macroscopic behavior (touch) with a microscopic one (atoms interacting). It is not consistent (example: the thermodynamic relationship between more temperature and more particular kinetic energy seems evident, but it's not: try looking the mathematics behind it: it's quite complex; essentially, the zeroth law of thermodynamics helps addressing such issue, just by saying that more temperature is just more energy in a very abstract way). If you want to understand the relation between touch and atoms interacting, study the systems and subsystems: what are the rules describing how solids are formed by particles; what are the rules describing how particles are formed by molecules; what are the rules describing how molecules are formed by atoms.


When you play any video game, some of the simulated objects are solid. Even in a simple side scroller like flappy bird, if the bird “touches” a pipe, the bird crashes and you start over. The game engine tracks the location of objects in the game world and provides appropriate feedback.

If we are living in a simulation, you don’t have a physical brain as such, it’s just code running on a computer somewhere. The state of your brain is determined by the simulation engine. Your brain state includes things like your location in space, what objects are around you, the sensation of gravity, the input of light… basically, all of your experiences. Touch is one of those experiences, and the simulation creates the brain state of a person touching something.

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