What is minimal about
minimal phenomenal experience?

Raphaël Millière

Ruhr-University Bochum / Columbia University

Slides: raphaelmilliere.com/slides/MPE

Defining MPE

Dreamless sleep experience is a candidate for minimal phenomenal experience, or the simplest form in which a state can be phenomenally conscious.
Windt (2015)

[This paper] develops the concept of “minimal phenomenal experience” (MPE) as a candidate for the simplest form of consciousness.
Metzinger (2020)

  • States of consciousness can me more or less simple
  • What is the relevant notion of simplicity?
  • Background: multidimensional model of consciousness
    Bayne et al. (2016)

Simplicity as a single dimension

What would this dimension be tracking?

  • Number of concurrent conscious contents?
  • ‘Bandwidth’ of experience?
  • Wakefulness/arousal?
  • Counterpoint: no levels of consciousness (Bayne et al.)

Simplicity as a global ordering


  • Meaningful agregation procedures?
  • Consider: height, blood pressure & wealth
    • Alice: [160, 120, 10000] (160cm, 120 mmHg, 10,000€)
    • Bob: [180, 115, 5000] (180cm, 115 mmHg, 5,000€)
  • Factor analysis of questionnaire items?
    • How to select items? Hobaynew many?
    • How to aggregate factors?

Simplicity as dimensionality

It may not be possible to isolate the simplest form of conscious experience in terms of one unique minimum of dimensionality for the relevant state-space (or an individual state displaying the minimal set of characteristic features), and for a given system multiple low-dimensional states may actually be possible or even co-exist. For example, in a 1,000,000-dimensional state space there might be five different kinds of three-dimensional states, each of them exhibiting a unique phenomenal character.
Metzinger (2020)


  • Counter-intuitive? [0, 0.9, 0.9] would be simpler than [0.1, 0.1, 0.1]
  • Less fine-grained
  • Much more dependent upon the dimensionality of the state-space

Oustanding questions

  • Reason for picking one notion of simplicity over others?
  • Is there a ground truth for any of these options?
  • Optimal (joint-carving) dimensionality?
  • How can the chosen notion be measured?

Thank you!