Ficino, Three Books on Life
Book 3 Chapter 3
But let us return to the spirit of the world. The world generates everything through it (since, indeed, all things generate through their own spirit); and we can call it both "the heavens" and "quintessence." It is practically the same thing in the world's body as in our body, with this primary exception, that the World-soul does not draw this spirit out of the four elements serving as her humors the way our soul does from our humors, but she procreates this spirit in the first instance (to speak Platonically, or rather Plotinically) as if pregnant by her own generative power, and the stars along with it. Immediately through the spirit the World-soul gives birth to the four elements, as though everything were contained in the power of that spirit. Spirit is a very tenuous body, as if now it were soul and now body, and now body and not soul. In its power there is very little of the earthy nature, but more of the watery, more likewise of the airy, and again the greatest proportion of the stellar fire. The very quantities of the stars and elements have come into being according to the measures of these degrees. This spirit assuredly lives in all as the proximate cause of all generation and motion, concerning which the poet said, "A Spirit nourishes within." It is wholly clear and hot by its own nature, moist, and life-giving, having acquired these gifts from the higher gifts of Soul.
Sed ad mundi spiritum redeamus, per quem mundus generat omnia, quandoquidem et per spiritum proprium omnia generant, quem tum coelum, tum quintum essentiam possumus appellare. Qui talis ferme est in corpore mundi, qualis in nostro noster, hoc imprimis excepto, quod anima mundi hunc non trahit ex quattuor elementis, tanquam humoribus suis, sicut ex nostris nostra, immo hunc proxime (ut Platonice sive Plotinice loquar) ex virtute sua procreat genitali, quasi tumens, et simul cum eo stellas, statimque per cum parit quattuor elementa, quasi non corpus et quasi iam anima, item quasi non anima et quasi iam corpus. In eius virtute minimum est naturae terrenae, plus autem aquae, plus item aeriae, rursus igneae stellarisque quam plurimum. Ad horum graduum mensuras ipsae quantitates stellarum elementorumque prodierunt. Ipse vero ubique viget in omnibus generationis omnis proximus auctor atque motus, de quo ille: "Spiritus intus alit." Totus est suapte natura lucidus calidusque et humidus atque vivificus, ex dotibus animae superioribus dotes eiusmodi nactus.