text: The last examples—disambiguating one’s fatigue and emo- 
  tional states—may seem strange if one assumes that we do have 
  direct access to the body- and allostasis-related states (e.g. states 
  of satiation, thirst, and fatigue) and to our emotions (e.g. we 
  automatically know whether we are happy or sad). However, one 
  assumption of active inference is that one’s bodily and emotional 
  states are not necessarily observable but, instead, “hidden states” 
  that need to be inferred on the basis of sensations (especially, 
  but not exclusively, of interoceptive sensations from the inside 
  of the body) and of an implicit, unconscious model of how the 
  body functions (Barrett and Simmons 2015, Pezzulo et al. 2015, 
  Seth and Friston 2016). In other words, the same inferential pro- 
  cess that allows active inference agents to estimate the hidden 
  state of the external environment (e.g. the presence or absence of 
  an object in the environment) is also used to estimate other hid- 
  den states, such as fatigue, happiness, or sadness. This implies 
  that one can also be wrong, or be fooled, about these states; for 
  example, we could experience the “interoceptive illusion” of feel- 
  ing more fatigued than our physiological parameters would afford 
  (Iodice et al. 2019). 