After reading a bit about qualia and hard problem of consiousness, I came up to theoretical solution. The reason why we have this problem is because we can imagine. We can imagine an object visible to us as red being green, for example. Green fire. Even if we never saw it in the reality.

But how do we imagine? How do those images have properties named by people as qualia? I can imagine a blue cube or a red cube, or a red sphere, and visual periphery is not involved here, I can do it with closed eyes.

What parts of our brain are responsible for imagination? How does the brain "give" qualia (form, color, smell, etc.) to images? What differs in my brain when I imagine a red cube from when I imagine a blue cube? And are qualia stored in our memory?


1 Answer 1


This is hardly settled science, but one hypothesis with some empirical support is that

Visual mental imagery and perception share similar cortical representations (Cichy et al., 2012; Kosslyn, 2005; Pylyshyn, 2003). It has been proposed that, while brain forward connections convey information from the outside world, backward connections might have a dominant role during the forming of mental images in the absence of external bottom-up inputs (Ganis and Schendan, 2008; Ishai et al., 2000; Kalkstein et al., 2011; Kosslyn, 2005).

For more theoretical speculation on the neural basis of qualia you could read Orpwood (2017), although by his own admittance, his ideas (at least in the past) were not terribly clearly presented. He does discuss a theoretical example of olfactory qualia. (I'm mentioning this because you said in the comments that you want to go beyond visual ones.)

Also note that some neuroscientists think the problem of qualia is ill-posed, in that it is intrinsically dualist:

Typically, qualia are defined by four characteristics. Qualia are private, meaning they cannot be known unless they are experienced through the first-person perspective. Qualia are intrinsic, which indicates that they are self-sufficient and independent of other items in experience. Qualia are also ineffable, signifying that the experience of qualia cannot be sufficiently conveyed through words alone. Finally, qualia are immediately accessible through consciousness, which means that knowledge of qualia is direct and certain, as opposed to knowledge of the physical world, which is indirect and logically deduced. [...]

This definition, unfortunately, leads us down a murky path towards dualism, a philosophical position which asserts that there are two kinds of real substances: the physical substance out of which the universe is composed, and the non-physical substance out of which the mind is composed.

Since you asked in the past about the private conceptions of word meanings (as a barrier to common sense), that kinda has the same problem.

If we just stick to qualia as brain processes/representation, regarding pain-related words, for example

Language is more than a mere medium when it comes to share our pain experiences. In fact, it has been shown that processing pain-related words is associated with enhanced activation of part of the neural circuitry underlying physical pain experiences. [citing four references in support]

  • Richter M, Eck J, Straube T, Miltner WH, Weiss T. Do words hurt? Brain activation during the processing of pain-related words. Pain. 2010 Feb;148(2):198–205. pmid:19846255

  • Richter M, Schroeter C, Puensch T, Straube T, Hecht H, Ritter A, et al. Pain-related and negative semantic priming enhances perceived pain intensity. Pain Res Manag. 2014 Mar-Apr;19(2):69–74. pmid:24716197

  • Gu X, Han S. Neural substrates underlying evaluation of pain in actions depicted in words. Behav Brain Res. 2007 Aug 6;181:218–23. pmid:17512615

  • Osaka N, Osaka M, Morishita M, Kondo H, Fukuyama H. A word expressing affective pain activates the anterior cingulate cortex in the human brain: an fMRI study. Behav Brain Res. 2004 Aug 12;153:123–127. pmid:15219713

I think this is somewhat analogous to the issue of V1 involvement in visual imagery.

  • $\begingroup$ Note, I asked about imagery in general, I can imagine a smell of strawberry jam. Probably, this is beyond visual imagery. Maybe it involves Aristotelian common sense (which is a part of the brain under presupposition of materialism - a position held in science), which distinguishes between sounds and tastes, and visions, and so on. $\endgroup$
    – rus9384
    Sep 23, 2018 at 18:14
  • $\begingroup$ @rus9384; although I'm unaware of empirical evidence for this, I can imagine that imagining smells might involve a similar reversal but using the olfactory areas. Anyway, you bringing up common sense here kind indicates that you don't have a simple/single in question in mind. The latter issue is more closely related to another question of yours that was closed here: psychology.stackexchange.com/questions/20606/… $\endgroup$
    – Fizz
    Sep 23, 2018 at 18:26
  • $\begingroup$ Damn, SE needs a notification for closed questions. In either way, it's not simple, but it's single. Imagining words? Hm, sounds strange. But still, there must be a difference when I imagine red and when I imagine blue. So, presumably it is in visual cortex. But then what prevents my visual cortex from producing a new color? $\endgroup$
    – rus9384
    Sep 23, 2018 at 18:36
  • $\begingroup$ Regarding words, for example "it has been shown that processing pain-related words is associated with enhanced activation of part of the neural circuitry underlying physical pain experiences". $\endgroup$
    – Fizz
    Sep 23, 2018 at 18:38
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    $\begingroup$ The purpose of this is exactly to think that qualia are physical. That there are physical differences when I think of blue versus when I think of red. Then we could see of there are physical differences between different individuals when they try to imagine the same thing. I would not go beyond the scope of that, because everything further is very likely to be untestable. $\endgroup$
    – rus9384
    Sep 23, 2018 at 19:42

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