Spinoza's Simplified Ethics. Part 2: The nature and origin of the mind, Propositions 16-30

Part 2: The Human Mind and Body

Proposition 16: The idea of every mode, in which the human body is affected by external bodies, must involve the nature of the human body, and also the nature of the external body.

Proof: All the modes, in which any given body is affected, follow from the nature of the body affected, and also from the nature of the affecting body (by Ax. 1, after the Coroll. of Lemma 3), wherefore their idea also necessarily (by 1. Ax. 4) involves the nature of both bodies.

1 & 2: It follows:
  1. That the human mind perceives the nature of a variety of bodies, together with the nature of its own.
  2. That the ideas, which we have of external bodies, indicate rather the constitution of our own body than the nature of external bodies.
    • I have amply illustrated this in the Appendix to Part 1.
Proposition 17: If the human body is affected in a manner which involves the nature of any external body, the human mind will regard the said external body as actually existing, or as present to itself, until the human body be affected in such a way, as to exclude the existence or the presence of the said external body.proposition is self—evident.mind is able to regard as present external bodies, by which the human body has once been affected, even though they be no longer in existence or present.external bodies determine the fluid parts of the human body, so that they often impinge on the softer parts, they change the surface of the last named (Post. 5).thus see how it comes about, as is often the case, that we regard as present many things which are not.Proposition 18: If the human body has once been affected by two or more bodies at the same time, when the mind afterwards imagines any of them, it will straightway remember the others also.mind (2.17. Coroll.) imagines any given body, because the human body is affected and disposed by the impressions from an external body, in the same manner as it is affected when certain of its parts are acted on by the said external body.now clearly see what Memory is.Proposition 19. The human mind has no knowledge of the body, and does not know it to exist, save through the ideas of the modifications whereby the body is affected.human mind is the very idea or knowledge of the human body (2.13), which (2.9) is in God, in so far as he is regarded as affected by another idea of a particular thing actually existing: or, inasmuch as (Post. 4) the human body stands in need of very many bodies whereby it is, as it were, continually regenerated; and the order and connection of ideas is the same as the order and connection of causes (2.7).Proposition 20: The idea or knowledge of the human mind is also in God, following in God in the same manner, and being referred to God in the same manner, as the idea or knowledge of the human body.is an attribute of God (2.1.).Proposition 21. This idea of the mind is united to the mind in the same way as the mind is united to the body.the mind is united to the body we have shown from the fact, that the body is the object of the mind (2.12 and 2.13).proposition is comprehended much more clearly from what we have said in the note to 2.7.Proposition 22: The human mind perceives not only the modifications of the body, but also the ideas of such modifications.ideas of the ideas of modifications follow in God in the same manner, and are referred to God in the same manner, as the ideas of the said modifications.Proposition 23: The mind does not know itself, except in so far as it perceives the ideas of the modifications of the body.idea or knowledge of the mind (2.20) follows in God in the same manner, and is referred to God in the same manner, as the idea or knowledge of the body.Proposition 24: The human mind does not involve an adequate knowledge of the parts composing the human body.parts composing the human body do not belong to the essence of that body, except in so far as they communicate their motions to one another in a certain fixed relation (Def. after Lemma 3), not in so far as they can be regarded as individuals without relation to the human body.Proposition 25. The idea of each modification of the human body does not involve an adequate knowledge of the external body.have shown that the idea of a modification of the human body involves the nature of an external body, in so far as that external body conditions the human body in a given manner.Proposition 26: The human mind does not perceive any external body as actually existing, except through the ideas of the modifications of its own body.the human body is in no way affected by a given external body, then (2.7) neither is the idea of the human body, in other words, the human mind, affected in any way by the idea of the existence of the said external body, nor does it in any manner perceive its existence.so far as the human mind imagines an external body, it has not an adequate knowledge thereof.the human mind regards external bodies through the ideas of the modifications of its own body, we say that it imagines (see 2.17 note).Proposition 27. The idea of each modification of the human body does not involve an adequate knowledge of the human body itself.idea of a modification of the human body involves the nature of the human body, in so far as the human body is regarded as affected in a given manner (2.16).Proposition 28: 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.ideas of the modifications of the human body involve the nature both of the human body and of external bodies (2.16).—The idea which constitutes the nature of the human mind is, in the same manner, proved not to be, when considered in itself alone, clear and distinct; as also is the case with the idea of the human mind, and the ideas of the ideas of the modifications of the human body, in so far as they are referred to the mind only, as everyone may easily see.Proposition 29: The idea of the idea of each modification of the human body does not involve an adequate knowledge of the human mind.idea of a modification of the human body (2.27) does not involve an adequate knowledge of the said body, in other words, does not adequately express its nature;it follows that the human mind, when it perceives things after the common order of nature, has not an adequate but only a confused and fragmentary knowledge of itself, of its own body, and of external bodies.say expressly, that the mind has not an adequate but only a confused knowledge of itself, its own body, and of external bodies, whenever it perceives things after the common order of nature;Proposition 30: We can only have a very inadequate knowledge of the duration of our body.duration of our body does not depend on its essence (2. Ax. 1), nor on the absolute nature of God (1.21).