Spinoza's Ethics: III.P1

Mens nostra quædam agit, quædam vero patitur nempe quatenus adæquatas habet ideas eatenus quædam necessario agit et quatenus ideas habet inadæquatas eatenus necessario quædam patitur.

Our mind does some things, truly it endures some things; indeed insofar as it has adequate ideas to such an extent does it do some things necessarily and insofar as it has inadequate ideas to such an extent does it endure some things necessarily.

DEMONSTRATIO: Cujuscunque humanæ mentis ideæ aliæ adæquatæ sunt, aliæ autem mutilatæ et confusæ (per scholia propositionis 40 partis II). Ideæ autem quæ in alicujus mente sunt adæquatæ, sunt in Deo adæquatæ quatenus ejusdem mentis essentiam constituit (per corollarium propositionis 11 partis II) et quæ deinde inadæquatæ sunt in mente, sunt etiam in Deo (per idem corollarium) adæquatæ non quatenus ejusdem solummodo mentis essentiam sed etiam quatenus aliarum rerum mentes in se simul continet. Deinde ex data quacunque idea aliquis effectus sequi necessario debet (per propositionem 36 partis I) cujus effectus Deus causa est adæquata (vide definitionem 1 hujus) non quatenus infinitus est sed quatenus data illa idea affectus consideratur (vide propositionem 9 partis II). At ejus effectus cujus Deus est causa quatenus affectus est idea quæ in alicujus mente est adæquata, illa eadem mens est causa adæquata (per corollarium propositionis 11 partis II). Ergo mens nostra (per definitionem 2 hujus) quatenus ideas habet adæquatas, quædam necessario agit, quod erat primum. Deinde quicquid necessario sequitur ex idea quæ in Deo est adæquata, non quatenus mentem unius hominis tantum sed quatenus aliarum rerum mentes simul cum ejusdem hominis mente in se habet, ejus (per idem corollarium propositionis 11 partis II) illius hominis mens non est causa adæquata sed partialis ac proinde (per definitionem 2 hujus) mens quatenus ideas inadæquatas habet, quædam necessario patitur. Quod erat secundum. Ergo mens nostra etc. Q.E.D.

Some ideas of whatsoever human mind are adequate, however others are mutilated and confused (by IIP40S). Moreover, ideas which are adequate in the mind of someone, are adequate in God insofar as God constitutes the essence of the person's mind (by IIP11C) and those which indeed are inadequate in the mind, are also adequate in God (by the same corollary) not insofar as the essence of the person's mind alone but also insofar as God contains the minds of other things in itself at the same time. Next from whatsoever given idea some effect ought to follow necessarily (by IP36) of whose effect God is the adequate cause (see IIID1) not insofar as God is infinite but insofar as the affect given by that idea is considered (see IIP9). But the person's effect of which God is the cause insofar as the affect is the idea which is adequate in the mind of someone else, that same mind is the adequate cause (by IIP11C). Thus our mind (by IIID2) insofar as it has adequate ideas, does some things necessarily, which was first. Next some thing follows necessarily from an idea which is adequate in God, not insofar as it has the mind of one person but only insofar as it has the minds of other things at the same time it has with the mind of this person in itself, whose (by IIP11C) mind of that man is not the adequate but partial cause and then (by IIID2) the mind insofar as it has inadequate ideas, endures some things necessarily. Which ought to follow. Thus our mind, etc.

COROLLARIUM: Hinc sequitur mentem eo pluribus passionibus esse obnoxiam quo plures ideas inadæquatas habet et contra eo plura agere quo plures habet adæquatas.

From this it follows that the mind is troubled in that direction by more passions to the extent that it has more inadequate ideas and against that direction it does more things to the extent that it has adequate ideas.

Spinoza's Ethics: III.Post.2

Spinoza outlines the fundamental basis for memory and thus thought and imagination by positing that the body is changed in some physical way that gives rise to a cognitive experience which reflects the change which occurred physically.

Corpus humanum multas pati potest mutationes et nihilominus retinere objectorum impressiones seu vestigia (de quibus vide postulatum 5 partis II) et consequenter easdem rerum imagines; quarum definitionem vide in scholio propositionis 17 partis II. 

The body of a human is able to endure changes and nothing less to retain the impressions of objects or vestiges (about which see II Post.5) and consequently the same images of things; whose definition see in IIP17S.

Spinoza's Ethics: III.Post1

Spinoza begins his approach to the human body as a form of physics - just as he indicated in the preface. The implicit physics here is the unity of the human body as a complex composite. This sets up that affecting some parts increases a power of acting while affecting other parts decreases a power of acting. Crucial to both affections is that the body retains its unity.

Corpus humanum potest multis affici modis quibus ipsius agendi potentia augetur vel minuitur et etiam aliis qui ejusdem agendi potentiam nec majorem nec minorem reddunt. Hoc postulatum seu axioma nititur postulato 1 et lemmatibus 5 et 7, quæ vide post propositionem 13 partis II.

The human body is able to be affected by many things in many ways by which the power of acting itself is increased or decreased and even by others which return the power of acting itself neither more nor less. This postulate or axiom is supported by Postulate 1 and Lemmas 5 and 7, which see after IIP13.

Spinoza's Ethics: III.D3: Affect

Per affectum intelligo corporis affectiones quibus ipsius corporis agendi potentia augetur vel minuitur, juvatur vel coercetur et simul harum affectionum ideas. Si itaque alicujus harum affectionum adæquata possimus esse causa, tum per affectum actionem intelligo, alias passionem.

By affect I understand modifications of the body by which the power of the body acting is increased or diminished, or helped or compelled and the ideas of these modifications at the same time. If in such a way we are able to be the adequate cause of some of these modifications, then by affect I understand action, otherwise passion.

Spinoza's Ethics: III.D2: Active Vs. Passive

Nos tum agere dico cum aliquid in nobis aut extra nos fit cujus adæquata sumus causa hoc est (per definitionem præcedentem) cum ex nostra natura aliquid in nobis aut extra nos sequitur quod per eandem solam potest clare et distincte intelligi. At contra nos pati dico cum in nobis aliquid fit vel ex nostra natura aliquid sequitur cujus nos non nisi partialis sumus causa.

Next I say that we are active when something in us or outside us happens of which we are the adequate cause, that is (by III.D1) when from our nature something in us or outside us follows which, through the same (nature) alone, is able to be understood clearly and distinctly. But in contrast I say that we are passive when in us something happens or from outside our nature something follows of which we are not the cause unless partially.  

Here Spinoza builds on the concept of adequate cause in the prior definition. The idea of being a sole cause is a high bar for adequacy. For example, it would seem that I am the cause of my breathing, but according to the rigor of Spinoza's definition, that does not seem true. I require oxygen for breathing and this is not something I generate myself. However, the part of the process of breathing which occurs after I have gotten oxygen may be an area in which I am the adequate cause. If this is true, then breathing is a complex process in which part of it is active (after getting oxygen) and the other part is passive (getting the oxygen).

Spinoza's Ethics: III.D1: Adequate Cause

Causam adæquatam appello eam cujus effectus potest clare et distincte per eandem percipi. Inadæquatam autem seu partialem illam voco cujus effectus per ipsam solam intelligi nequit.

I name an adequate cause that whose effect is able to be perceived clearly and distinctly. Moreover I call that an inadequate or partial cause whose effect is not able to be understood through itself alone.

Spinoza starts his three book discussion on human affects with causal clarity. He is interested in calling something an adequate cause based on the effect that it generates. This first step is important as his approach is based on many of the human affects being grounded in biases. Adequacy is an attempt to remove biases.