Yes. The nature of the human intellect is not only incorporeal, but it is also a substance, that is, something subsistent because if the intellectual principle contained the nature of a body it would be unable to know all bodies.
Natura mentis humanae non solum est incorporea, sed etiam substantia, scilicet aliquid subsistens quod si igitur principium intellectuale haberet in se naturam alicuius corporis, non posset omnia corpora cognoscere.
Now every body has its own determinate nature. Therefore it is impossible for the intellectual principle to be a body. It is likewise impossible for it to understand by means of a bodily organ; since the determinate nature of that organ would impede knowledge of all bodies.
Omne autem corpus habet aliquam naturam determinatam. Impossibile est igitur quod principium intellectuale sit corpus. Et similiter impossibile est quod intelligat per organum corporeum, quia etiam natura determinata illius organi corporei prohiberet cognitionem omnium corporum.
Therefore the intellectual principle which we call the mind or the intellect has an operation "per se" apart from the body. Now only that which subsists can have an operation "per se." For nothing can operate but what is actual.
Ipsum igitur intellectuale principium, quod dicitur mens vel intellectus, habet operationem per se, cui non communicat corpus. Nihil autem potest per se operari, nisi quod per se subsistit. Non enim est operari nisi entis in actu, unde eo modo aliquid operatur, quo est.
The body is necessary for the action of the intellect, not as its origin of action, but on the part of the object; for the phantasm is to the intellect what color is to the sight. Neither does such a dependence on the body prove the intellect to be non-subsistent; otherwise it would follow that an animal is non-subsistent, since it requires external objects of the senses in order to perform its act of perception.
Corpus requiritur ad actionem intellectus, non sicut organum quo talis actio exerceatur, sed ratione obiecti, phantasma enim comparatur ad intellectum sicut color ad visum. Sic autem indigere corpore non removet intellectum esse subsistentem, alioquin animal non esset aliquid subsistens, cum indigeat exterioribus sensibilibus ad sentiendum.
We must conclude, therefore, that the human soul, which is called the intellect or the mind, is something incorporeal and subsistent.
Relinquitur igitur animam humanam, quae dicitur intellectus vel mens, esse aliquid incorporeum et subsistens.
Augustine says (De Trin. x, 7): "Who understands that the nature of the soul is that of a substance and not that of a body, will see that those who maintain the corporeal nature of the soul, are led astray through associating with the soul those things without which they are unable to think of any nature--i.e. imaginary pictures of corporeal things."
Augustinus dicit, X de Trin. "Quisquis videt mentis naturam et esse substantiam, et non esse corpoream, videt eos qui opinantur eam esse corpoream, ob hoc errare, quod adiungunt ei ea sine quibus nullam possunt cogitare naturam, scilicet corporum phantasias."