'...quo plus..., eo plus ... ' translation?

Question

Here is a really complicated sentence, I am trying to understand how to translate it:

Nam cum posse existere potentia sit, sequitur quo plus realitatis alicujus rei naturæ competit eo plus virium a se habere ut existat adeoque Ens absolute infinitum sive Deum infinitam absolute potentiam existendi a se habere, qui propterea absolute existit.(Spinoza, Ethics)

For, as the potentiality of existence is a power, it follows that, in proportion as reality increases in the nature of a thing, so also will it increase its strength for existence. Therefore a being absolutely infinite, such as God, has from himself an absolutely infinite power of existence, and hence he does absolutely exist. (R.H.M.Elwes)

The first part I understand -

Cum + Subjunctive - Nam cum posse existere potentia (f.Nom.) sit,

it follows that - sequitur

now comes that part which I found difficult -

quo plus realitatis alicuius rei naturae competit

so what is subject for competit, if it is potentia, then it would be qua? Plus is followed by Partitive Genitive and more Genitives here - so should I translate it 'more reality of some nature of a thing'?

competo - 2. Of other things, to agree or coincide with something, to answer to it

Next comes

eo plus virium -

again Partitive Genitive , so ' more strength to, of, something', again it is unclear what is the subject, should be the same as for 'quo' but what is it?

then

a se habere ut existat (ut + Sub.)

'it could (have something to) exist from itself' -does it belong to the first half of the sentence?

Answer 1

The first thing to observe here is the quo–eo structure. For example:

Quo plus edo, eo laetior sum.
The more I eat, the happier I am.

Therefore quo plus…eo plus means "the more…the more". In the translation you quote this is rendered as "as reality increases, so also will increase". These quo and eo are neuter ablatives, but it might be better to see the pair as a fixed phrase.

The second confusing thing is the use of partitive genitives. Here plus realitatis means "more reality" and plus virium is "more strength". The subject of competit is plus realitatis.

If I understand correctly, naturae is dative, not genitive. The basic idea is this:

Realitas naturae competit.
Reality meets (or increases in) nature.

There are many other structures, but expanding around this short phrase helps make sense of quo plus realitatis alicujus rei naturæ competit.

I find the passage eo plus virium a se habere ut existat confusing, so my interpretation may be off. Here ut existat is a final ut clause "so that he may exist", and it is best paired with vires. I read plus virium ut existat as "more strength to exist". The source of the strength is the entity under discussion, the strength comes from it (a se).

The infinitive sounds weird to me. I would read the first half of your passage like this, simplifying or rewording into different versions:

Nam cum posse existere potentia sit, sequitur quo plus realitatis alicujus rei naturæ competit eo plus virium a se habet ut existat.
Potentia est posse existere. Itaque, quo plus realitatis naturae competit, eo plus virium habet. Vires habet, ut existat.
Si existere potest, potentiam habet. Realitas naturae competit, et vires habet. Vires habet, ut existat.

I would therefore translate this part as follows:

The ability to exist is a power. Therefore it follows: the more reality there is in the nature of some thing, the more strength it has to exist.

This agrees more or less with the translation you have. Do ask if something needs more explanation.