So the great _Summa theologiae_ of Thomas Aquinas adopts the same order which the Lombard had followed. The _Pars prima_ begins with defining _sacra doctrina_.[446] It then proceeds to consider God--whether He exists; then treats of His _simplicitas_ and _perfectio_; next of His attributes; His _bonitas_, _infinitas_, _immutabilitas_, _aeternitas_, _unitas_; then of our knowledge of Him; then of His knowledge, and therein of truth and falsity; thereupon are considered the divine will, love, justice, and pity; the divine providence and predestination; the divine power and beatitude. All this pertains to the _unitas_ of the divine essence; and now Thomas passes on to the _Trinitas personarum_, or the more distinctive portions of Christian theology. He treats of the _processio_ and _relationes_ of the _divinae Personae_, and then of themselves--Father, Son, Holy Spirit, and then of their essential relationship and properties. Next he discusses the _missio_ of the divine Persons, and the relations between God and His Creation. First comes the consideration of the principle of creation, the _processio creaturarum a Deo_, and of the nature of created things, with some discussion of evil, whether it be a thing. Among created beings, Thomas treats first of angels, and at great length; then of the physical creation, in its order--the work of the six days, but with no great detail. Then man, created of spiritual and corporeal substance--his complex nature is to be analysed and fathomed to its depths. Thomas discusses the union of the _anima ad corpus_; then the powers of the anima, _in generali_ and _in speciali_--the intellectual faculties, the appetites, the will and its freedom of choice; how the _anima_ knows--the full Aristotelian theory of cognition is given. Next, more specifically as to the creation of the soul and body of the first man, and the nature of the image and similitude of God within him; then as to man’s condition and faculties while in a state of innocence; also as to Paradise. This closes the treatment of the _creatio et distinctio rerum_; and Thomas passes to their _gubernatio_, and the problem of how God conserves and moves the corporeal and spiritual; then concerning the action of one creature on another, and how the angels are ranged in hierarchies, and although purely spiritual beings, minister to men and guard them; then concerning the action of corporeal things, concerning fate, and the action of men upon men. Here ends _Pars prima_. The first section of the second part (_Prima secundae_) begins. In a short Prologue Thomas says: