{1d01 causa sui}

Meaning | Self-caused. Definition {1d01} does not define causa, a philosophical primitive term (cf. pp1d01 causa^effectus) the meaning of which is extending far beyond the range of causa sui. Neither does it define sui ("its", "of itself"), which is treated in this web as a philosophical primitive as well (pp1d01 se^alius). {1d01} defines the 9-digit string "causa sui", in quite a technical and complicated way (details below) locally overriding the meaning of the primitives causa and sui. Being causa sui implies being eternal {1d08} (see below quote of {1d08} and quote of {1p19}. Only one thing, it will turn out, is causa sui. It carries three names: God = natura-sense 2 = substance. Attributes are infinite but not causa sui. All other things (res) are can be adequately / partially / accidentally caused, and will themselves be infinite only if adequately caused by something infinite. The rest of things is finite, that is: caused by other finite things that in turn are caused by other finite things etc. until infinity (that is: the infinity in suo genere of their attributes, not the absolute infinity of God = natura-sense 2 = substance = causa sui).
Related concepts | Causa sui is formally defined equivalent to aeternus = [prf eqv] infinitus, but in practical use has the more specific "no-negation" meaning of absolute infinitus, a property only of God = natura-sense 2 = substance. "Debet per se concipere" is weaker than "est causa per se" the latter applying only to God, the former to attributes as well (e.g. {1p10}).
Occurrence | [geomap] Rare (5 occurences), near-redundant and formally slightly under-specified (see "Related concepts" above), hence puzzling to the reader seeing it as the very first definition of Ethica.
NOT linked: | Wherever sui and causa are not used as in the 9-digit separately defined string causa sui or its grammatical equivalents (e.g. in "causa est sui"), causa is linked to pp1d01 causa^effectus and sui, where relevant, to pp1d01 se^alius.

{1d01 causa sui} ... an extremely rough start for the student - for the full understanding of this rarely used definition you first need to have understood a number of later deductive elements of Ethica Pars Prima ... two highly technical and complicated strings expressing the same meaning ... a bit under-specified: since causa sui formally gets defined as only equivalent to infinitus (which includes attributes) ... but immediately gets specifically used for absolute infinitus (which excludes attributes, more below and in {1d02 in suo genere finitus ^ absoluta finitus}) ...
... that which is self-caused ... that of which the essence involves existence, or that of which the nature is only conceivable as existent. | ... causam sui ... id cujus essentia involvit existentiam sive [mng-eqv] id cujus natura non potest concipi nisi existens.

1d06e absolutus-suo genere infinitus ... absolutus explained ... to mean NOT-in-suo-genere infinite, which means NO negation ... this NO-negation clause is distinguishing God = natura-sense 2 = substance = causa sui from other infinite things hence should have been included in the formal definition of causa sui ...
... I say absolutely infinite, not infinite after its kind: for, of a thing infinite only after its kind, infinite attributes may be denied; but that which is absolutely infinite, contains in its essence whatever expresses reality, and involves no negation. | ... Dico absolute infinitum, non autem in suo genere; quicquid enim in suo genere tantum infinitum est, infinita de eo attributa negare possumus; quod autem absolute infinitum est, ad ejus essentiam pertinet quicquid essentiam exprimit et negationem nullam involvit.

{1d08 aeternitas} ... Aeternitas is defined by calling aeternus a thing from the essence (="what is entailed by its definition") of which follows its existence ... hence being causa sui implies being aeternus. More: see notes-quote of {1p19} ...
... By eternity, I mean existence itself, in so far as it is conceived necessarily to follow solely from the definition of that which is eternal. | ... Per aeternitatem intelligo ipsam existentiam quatenus ex sola rei aeternae definitione necessario sequi concipitur.

1p10s attributa non entia sive substantias distincta ... why there must be an infinite number of attributes (though we perceive things only in two) ... note the absence of absolute when dealing with (infinite) attributes ... God is absolutely infinite / causa sui but attributes are not (even though attributes formally conform definition {1d01} of causa sui, which hence is too weak and should have contained the "no negation"-clause) ...
... each and every entity must be conceived under some attribute, and ... its reality or being is in proportion to the number of its attributes expressing necessity or eternity and infinity. Consequently it is abundantly clear, that an absolutely infinite being must necessarily be defined as consisting in infinite attributes, each of which expresses a certain eternal and infinite essence ... | ... unumquodque ens sub aliquo attributo debeat concipi et quo plus realitatis aut esse habeat eo plura attributa quae et necessitatem sive aeternitatem et infinitatem exprimunt, habeat et consequenter nihil etiam clarius quam quod ens absolute infinitum necessario sit definiendum (ut definitione 6 tradidimus) ens quod constat infinitis attributis quorum unumquodque aeternam et infinitam certam essentiam exprimit ...

{1p19 Deus aeterna} ... a string of {1p07}: "Ad naturam substantiae pertinet existere, used here as a premiss for proof and rephrased for the purpose using an other, equivalent, term aeternitas ... hence saying "it belongs to its nature (=essence) to exist" means the same as saying "it is eternal" and being causa sui formally means eternal (in subsequent use restricted to absolutely infinite) ...
... God, and all the attributes of God, are eternal. | ... Deus sive [non-excl exh] omnia Dei attributa sunt aeterna.
... eternity appertains to the nature of substance (as I have already shown in Prop. vii.); therefore, eternity must appertain to each of the attributes, and thus all are eternal. | ... ad naturam substantiae (ut jam ex propositione 7 demonstravi {1p07}) pertinet aeternitas. Ergo unumquodque attributorum aeternitatem involvere debet adeoque omnia sunt aeterna ...

Equivalence claims involving (causa) sui
{1d01} [notes] | 1. cause of itself 2. that of which the essence involves existence 3. that of which the nature cannot be understood except in state of existence | 1. causa sui 2. [id cujus] essentia involvit existentiam 3. id cujus natura non potest concipi nisi existens.
{1p07} | 1. be its own cause 2. its essence necessarily involves existence 3. existence belongs to its nature. | 1. est causa sui 2. ipsius essentia involvit necessario existentiam 3. ad ejus naturam pertinet existere.