Propositions 21 to 30

21. This idea of the mind is united to the mind in the same way as the mind is united to the body.

22. The human mind perceives not only the modifications of the body, but also the ideas of such modifications.

  1. The mind does not know itself, except in so far as it perceives the ideas of the modifications of the body.
  1. The human mind does not involve an adequate knowledge of the parts composing the human body.
  1. The idea of each modification of the human body does not involve an adequate knowledge of the external body.
  1. The human mind does not perceive any external body as actually existing, except through the ideas of the modifications of its own body.
  1. The idea of each modification of the human body does not involve an adequate knowledge of the human body itself.
  1. The ideas of the modifications of the human body, in so far as they have reference only to the human mind, are not clear and distinct, but confused.
  1. The idea of the idea of each modification of the human body does not involve an adequate knowledge of the human mind.
  1. We can only have a very inadequate knowledge of the duration of our body.