Spinoza's Ethics: III.P8

Conatus quo unaquæque res in suo esse perseverare conatur, nullum tempus finitum sed indefinitum involvit.

The trying by which each and every thing tries to persist to be in itself, involves no finite time, but an indefinite one.

DEMONSTRATIO: Si enim tempus limitatum involveret quod rei durationem determinaret, tum ex sola ipsa potentia qua res existit, sequeretur quod res post limitatum illud tempus non posset existere sed quod deberet destrui; atqui hoc (per propositionem 4 hujus) est absurdum : ergo conatus quo res existit, nullum tempus definitum involvit sed contra quoniam (per eandem propositionem 4 hujus) si a nulla externa causa destruatur, eadem potentia qua jam existit, existere perget semper, ergo hic conatus tempus indefinitum involvit. Q.E.D.

For if time involves a limitation which determines the duration of the thing, then from only the power itself by which the thing exists, it follows that the thing is not able to exist after that time limitation but ought to be destroyed; and so this (by IIIP4) is absurd; thus trying by which the thing exists, involves no definite time but against since (by IIIP4) if it is destroyed by no external cause, the same power by which it now exists, it always goes on to exist, thus trying involves an indefinite time here. 

Spinoza is articulating some persistence here. He seems to imply some effort but this would be a mischaracterization given the physics tone of his writing. One idea might be that this persistence captures some kind of energy flow that resembles an entropy move based on the interactions of physical structures. That is, because each thing has this persistence and exists within the persistence patterns of the things around it, then the thing itself exists as an energy-entropy flow which shows up as expression. This is expression is something like the play-doh getting pressed out of form making. As a result, the thing itself does not go away internally as to its structure, but due to forces outside of it. Yet this implies that the energy that powers its expression does not diminish and perhaps that warrants some thought.

Spinoza's Ethics: III.P7 - Efforting

Conatus quo unaquæque res in suo esse perseverare conatur, nihil est præter ipsius rei actualem essentiam.

The efforting by which each and every thing tries to persevere to be in itself, is nothing other than the actual essence of the thing itself.

DEMONSTRATIO: Ex data cujuscunque rei essentia quædam necessario sequuntur (per propositionem 36 partis I) nec res aliud possunt quam id quod ex determinata earum natura necessario sequitur (per propositionem 29 partis I); quare cujuscunque rei potentia sive conatus quo ipsa vel sola vel cum aliis quidquam agit vel agere conatur hoc est (per propositionem 6 hujus) potentia sive conatus quo in suo esse perseverare conatur, nihil est præter ipsius rei datam sive actualem essentiam. Q.E.D.

From the given essence of whatsoever thing, certain things follow necessarily (by IP36) and no things are able to be something than that which follows necessarily from nature determining of them (by IP29); thus the power of whatsoever thing or the trying by which itself or alone or with others something acts or tries to act, that is (by IIIP6) the power or trying by which it tries to persevere in being in itself, is nothing other than the given or actual essence of the thing itself.

This word conatus implies some effort or attempt by a thing. This is not simply resting while the scratch on my arm heals. Instead, Spinoza is stating that things manifest their potentia as trying to persevere. This trying is the essence of the thing as it reflects the specific form of potentia which is the expressive force of substance or God. Prior to my study of Spinoza, I would have assumed that the formal essence or idea of the thing was the essence of the thing. However, the essence of the thing is the manifestation of the potentia, which is the contatus.

Spinoza's Ethics: III.P6 - Persevering in Itself

Unaquæque res quantum in se est, in suo esse perseverare conatur.

Howsoever much a thing in itself, it tries to persist being in itself.

DEMONSTRATIO: Res enim singulares modi sunt quibus Dei attributa certo et determinato modo exprimuntur (per corollarium propositionis 25 partis I) hoc est (per propositionem 34 partis I) res quæ Dei potentiam qua Deus est et agit, certo et determinato modo exprimunt neque ulla res aliquid in se habet a quo possit destrui sive quod ejus existentiam tollat (per propositionem 4 hujus) sed contra ei omni quod ejusdem existentiam potest tollere, opponitur (per propositionem præcedentem) adeoque quantum potest et in se est, in suo esse perseverare conatur. Q.E.D.

For singular things are modes by which the attributes of God are expressed in a certain and determinate mode (by IP25C), that is (by IP34) things which express by a certain and determinate mode the power of God by which God is and acts, and nothing has something else in itself by which it is able to be destroyed or which destroys its existence (by IIIP4) but placed against all else which is able to destroy its same existence (by IIIP5)  to the extent that it is much and is in itself, it tries to persevere being in itself.

Here Spinoza sets up the almost inertial power of modes or singular things - they tend to persist even though they are rooted in and express the power of God. The tendency of modes to do this is viewed objectively at this point, but its attempting or trying to do something sets up the subjective element to modes.

Spinoza's Ethics: III.P5 - Self-Contradiction

Res eatenus contrariæ sunt naturæ hoc est eatenus in eodem subjecto esse nequeunt quatenus una alteram potest destruere.

Things are contrary to an extent, that is, their natures are unable to exist thus in the same subject to the extent that one might destroy the other.

DEMONSTRATIO: Si enim inter se convenire vel in eodem subjecto simul esse possent, posset ergo in eodem subjecto aliquid dari quod ipsum posset destruere, quod (per propositionem præcedentem) est absurdum. Ergo res etc. Q.E.D.

For if they are able to join among themselves or be in the same subject at the same time, thus something is able to exist in the same subject which might destroy itself which (by IIIP4) is absurd. 

Here Spinoza is being propositional - inherent self-contradictions cannot exist. This is a fundamental stance of rationalists versus empiricists. Empiricists can embrace self-contradictions, e.g. a wave can't be a particle and vice versa, yet seems to do so in basic atomic physics. Rationalists cannot as logic is the structure of a coherent universe.

Spinoza's Ethics: III.P4

Nulla res nisi a causa externa potest destrui.

There is no thing able to be destroyed unless it is by an external cause.

DEMONSTRATIO: Hæc propositio per se patet; definitio enim cujuscunque rei ipsius rei essentiam affirmat sed non negat sive rei essentiam ponit sed non tollit. Dum itaque ad rem ipsam tantum, non autem ad causas externas attendimus, nihil in eadem poterimus invenire quod ipsam possit destruere. Q.E.D.

This proposition is evident through itself: for the definition of whatsoever thing itself affirms the essence of the thing but it does not deny or it places the essence but does not remove it. Thus as long as we attend so to the thing itself, moreover not to external causes, we are able to find nothing in the same which is able to destroy itself. 

In this proposition, Spinoza describes a tendency of a thing to persist - only externals remove or alter a thing. This inherent quality of things to persist provides a key part of the fabric of the material world. A thing whose essence is not to persist would be self-contradictory and form an unstable system. This certainly seems true at the visible scale of our world. However, it does seem like some sub-atomic dynamics contradict this proposition.

Spinoza's Ethics: III.P3

Mentis actiones ex solis ideis adæquatis oriuntur, passiones autem a solis inadæquatis pendent.

The actions of the mind arise from only adequate ideas, meanwhile the passions weigh from only inadequate ones.

DEMONSTRATIO: Primum quod mentis essentiam constituit, nihil aliud est quam idea corporis actu existentis (per propositiones 11 et 13 partis II) quæ (per propositionem 15 partis II) ex multis aliis componitur quarum quædam (per corollarium propositionis 38 partis II) sunt adæquatæ, quædam autem inadæquatæ (per corollarium propositionis 29 partis II). Quicquid ergo ex mentis natura sequitur et cujus mens causa est proxima per quam id debet intelligi, necessario ex idea adæquata vel inadæquata sequi debet. At quatenus mens (per propositionem 1 hujus) ideas habet inadæquatas eatenus necessario patitur; ergo mentis actiones ex solis ideis adæquatis sequuntur et mens propterea tantum patitur quia ideas habet inadæquatas. Q.E.D.

First what establishes the essence of the mind, nothing other than which the idea of the existence of the actual body (by IIP11 and IIP13) which (by IIP15) is made up of many others of which certain (by IIP38C) are adequate, moreover certain are inadequate (by IIP29C). Thus whatever follows from the nature of the mind and of which the mind is the exact cause by which it ought to be understood, ought to follow necessarily from an idea either adequate or inadequate. But insofar as the mind (by IIIP1) has inadequate ideas it necessarily suffers thus far; therefore the actions of the mind follow from the adequate ideas alone and meanwhile the mind suffers so much because it has inadequate ideas.

SCHOLIUM: Videmus itaque passiones ad mentem non referri nisi quatenus aliquid habet quod negationem involvit sive quatenus consideratur ut naturæ pars quæ per se absque aliis non potest clare et distincte percipi et hac ratione ostendere possem passiones eodem modo ad res singulares ac ad mentem referri nec alia ratione posse percipi sed meum institutum est de sola mente humana agere.

Thus we see passions do not refer to the mind unless insofar as something which involves negation or insofar as it is considered that a part of nature which is not able to be perceived clearly and distinctly through itself and from others and by this way I am able to show that the passions in this way refer to singular things as to the mind and not by some other way are able to be perceived but is my principle to discuss concerning the human mind.  

Here Spinoza attempts a first discussion of the passions. His use of the verb pendere in contrast to oriri is interesting as an illustration of the power of actions versus the weight of passions. The scholium discusses that passions are either (from a thinking attribute) a negation or (from an extending attribute) a dysfunction of the body in its incapacity. This sets up that passions are truly extending things in Spinoza's parallelism. Thus, imaginations of the mind do have place in the attribute of extending. But Spinoza clarifies that he is only going to address those of the human mind or the attribute of thinking. This is important because it often seems that Spinoza's focus on imagination creates a non-match in his parallelism.