Yes. The soul can understand when it is apart from the body because it has a proper operation and above all that which consists in intelligence.
Anima intelligit sine corpore existens quia habet aliquam operationem propriam et maxime eam quae est intelligere.
The separated soul does not understand by way of innate species, nor by species abstracted then, nor only by species retained ... but the soul in that state understands by means of participated species arising from the influence of the Divine light, shared by the soul as by other separate substances, though in a lesser degree.
Anima separata non intelligit per species innatas, nec per species quas tunc abstrahit, nec solum per species conservatas ... sed per species ex influentia divini luminis participatas, quarum anima fit particeps sicut et aliae substantiae separatae, quamvis inferiori modo.
Hence as soon as it ceases to act by turning to corporeal [phantasms], the soul turns at once to the superior things; nor is this way of knowledge unnatural, for God is the author of the influx of both of the light of grace and of the light of nature.
Unde tam cito cessante conversione ad corpus, ad superiora convertitur. Nec tamen propter hoc cognitio non est naturalis, quia Deus est auctor non solum influentiae gratuiti luminis, sed etiam naturalis.
As nothing acts except so far as it is actual, the mode of action in every agent follows from its mode of existence. Now the soul has one mode of being when in the body, and another when apart from it, its nature remaining always the same; but this does not mean that its union with the body is an accidental thing, for, on the contrary, such union belongs to the formal aspect of its nature.
Cum nihil operetur nisi inquantum est actu, modus operandi uniuscuiusque rei sequitur modum essendi ipsius. Habet autem anima alium modum essendi cum unitur corpori, et cum fuerit a corpore separata, manente tamen eadem animae natura; non ita quod uniri corpori sit ei accidentale, sed per rationem suae naturae corpori unitur.
The soul, therefore, when united to the body, consistently with that mode of existence, has a mode of understanding, by turning to corporeal phantasms, which are in corporeal organs; but when it is separated from the body, it has a mode of understanding, by turning to simply intelligible objects, as is proper to other separate substances.
Animae igitur secundum illum modum essendi quo corpori est unita, competit modus intelligendi per conversionem ad phantasmata corporum, quae in corporeis organis sunt; cum autem fuerit a corpore separata, competit ei modus intelligendi per conversionem ad ea quae sunt intelligibilia simpliciter, sicut et aliis substantiis separatis.
Hence it is as natural for the soul to understand by turning to the phantasms as it is for it to be joined to the body; but to be separated from the body is beyond the formal aspect of its nature, and likewise to understand without turning to the phantasms is beyond its nature; and hence it is united to the body in order that it may have an existence and an operation suitable to its nature.
Unde modus intelligendi per conversionem ad phantasmata est animae naturalis, sicut et corpori uniri, sed esse separatum a corpore est praeter rationem suae naturae, et similiter intelligere sine conversione ad phantasmata est ei praeter naturam. Et ideo ad hoc unitur corpori, ut sit et operetur secundum naturam suam.
Now it is clear that in the natural order human souls hold the lowest place among intellectual substances. But the perfection of the universe required various grades of being. If, therefore, God had willed souls to understand in the same way as separate substances, it would follow that human knowledge, so far from being perfect, would in general be confused.
Manifestum est autem inter substantias intellectuales, secundum naturae ordinem, infimas esse animas humanas. Hoc autem perfectio universi exigebat, ut diversi gradus in rebus essent. Si igitur animae humanae sic essent institutae a Deo ut intelligerent per modum qui competit substantiis separatis, non haberent cognitionem perfectam, sed confusam in communi.
Therefore to make it possible for human souls to possess perfect and proper knowledge, they were so made that their nature required them to be joined to bodies, and thus to receive the proper and adequate knowledge of sensible things from the sensible things themselves; thus we see in the case of uneducated men that they have to be taught by sensible examples.
Ad hoc ergo quod perfectam et propriam cognitionem de rebus habere possent, sic naturaliter sunt institutae ut corporibus uniantur, et sic ab ipsis rebus sensibilibus propriam de eis cognitionem accipiant; sicut homines rudes ad scientiam induci non possunt nisi per sensibilia exempla.
The Philosopher says (De Anima i, 1), "If the soul had no proper operation, it could not be separated from the body."
Philosophus dicit, in I de anima, quod "si non est aliqua operationum animae propria, non contingit ipsam separari."