Spinoza's Ethics: II.D1: Body

Here is the first step into what seems the most difficult of all of Spinoza's writings - Part 2 of the Ethics concerning the mind. In order to address it, he first defines that which is not the mind - the body. The body is a mode under the aspect of extending. 

Part 1 says that nothing exists except substance and modes. Clearly the body is not substance as it can be conceived as not existing and so the body is a mode. The mode expresses. God does not conceive a plan or an end, but expresses power. What is expressed as a mode is the essence of God. The essence of God is existence (I.D1). This existence is expressed in a certain and determinate way through the aspect of extending.

These points are important about certain and determinate: 1) it's all God, all the time, so no real thing exists that does not express the essence of God, 2) God's expressive nature is full or jam packed, meaning that any mode exists as fully as possible and is not limited internally but by something else (I.D2). This sense of limitation externally makes Spinoza's "certain and determinate way" different than that of others, who define limits from within. 

As background, Spinoza embarks on a response to Descartes who held that a mind-body dualism exists. Spinoza denies this dualism by establishing the unity of substance, yet confirms the perception of duality by developing the notion of attributes in which at least two exist. I am translating res extensa as "the extending aspect" because that translation conveys the sense of the role unity and yet distinction of attribute here.

Language note: Translators tend to translate the subject of consideratur or "is considered" as God. I think this is incorrect and misleading. Latin's ambiguity as well as Spinoza's brevity is at fault. The word ut or "as" introduces the present passive indicative phrase with a third person singular verb. Res or "aspect" (as I have translated it) could be nominative singular or nominative plural or accusative plural. Since consideratur is passive and does not take an object, the choices are a singular or plural subject and the number indicates singular. Thus, the only rendering is res extensa as subject. This limits the consideration to res extensa in contrast to res cogitans, rather than God.

Per corpus intelligo modum qui Dei essentiam quatenus ut res extensa consideratur, certo et determinato modo exprimit; vide corollarium propositionis 25 partis I.

Translated as,

By the body, I understand a mode which expresses the essence of God in a certain and determinate way, insofar as the extending aspect is considered. See IP25C.