Objection 1: It would seem that the soul separated from the body can understand nothing at all. For the Philosopher says (De Anima i, 4) that "the understanding is corrupted together with its interior principle." But by death all human interior principles are corrupted. Therefore also the intellect itself is corrupted.

Objection 2: Further, the human soul is hindered from understanding when the senses are tied, and by a distracted imagination, as explained above (Question [84], Articles [7],8). But death destroys the senses and imagination, as we have shown above (Question [77], Article [8]). Therefore after death the soul understands nothing.

Objection 3: Further, if the separated soul can understand, this must be by means of some species. But it does not understand by means of innate species, because it has none such; being at first "like a tablet on which nothing is written": nor does it understand by species abstracted from things, for it does not then possess organs of sense and imagination which are necessary for the abstraction of species: nor does it understand by means of species, formerly abstracted and retained in the soul; for if that were so, a child's soul would have no means of understanding at all: nor does it understand by means of intelligible species divinely infused, for such knowledge would not be natural, such as we treat of now, but the effect of grace. Therefore the soul apart from the body understands nothing.

On the contrary, The Philosopher says (De Anima i, 1), "If the soul had no proper operation, it could not be separated from the body." But the soul is separated from the body; therefore it has a proper operation and above all, that which consists in intelligence. Therefore the soul can understand when it is apart from the body.

I answer that, The difficulty in solving this question arises from the fact that the soul united to the body can understand only by turning to the phantasms, as experience shows. Did this not proceed from the soul's very nature, but accidentally through its being bound up with the body, as the Platonists said, the difficulty would vanish; for in that case when the body was once removed, the soul would at once return to its own nature, and would understand intelligible things simply, without turning to the phantasms, as is exemplified in the case of other separate substances. In that case, however, the union of soul and body would not be for the soul's good, for evidently it would understand worse in the body than out of it; but for the good of the body, which would be unreasonable, since matter exists on account of the form, and not the form for the sake of matter. But if we admit that the nature of the soul requires it to understand by turning to the phantasms, it will seem, since death does not change its nature, that it can then naturally understand nothing; as the phantasms are wanting to which it may turn.

To solve this difficulty we must consider that 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 its very nature, just as the nature of a light object is not changed, when it is in its proper place, which is natural to it, and outside its proper place, which is beside its nature. 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. 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 not in accordance with its nature, and likewise to understand without turning to the phantasms is not natural to it; and hence it is united to the body in order that it may have an existence and an operation suitable to its nature. But here again a difficulty arises. For since nature is always ordered to what is best, and since it is better to understand by turning to simply intelligible objects than by turning to the phantasms; God should have ordered the soul's nature so that the nobler way of understanding would have been natural to it, and it would not have needed the body for that purpose.

In order to resolve this difficulty we must consider that while it is true that it is nobler in itself to understand by turning to something higher than to understand by turning to phantasms, nevertheless such a mode of understanding was not so perfect as regards what was possible to the soul. This will appear if we consider that every intellectual substance possesses intellective power by the influence of the Divine light, which is one and simple in its first principle, and the farther off intellectual creatures are from the first principle so much the more is the light divided and diversified, as is the case with lines radiating from the centre of a circle. Hence it is that God by His one Essence understands all things; while the superior intellectual substances understand by means of a number of species, which nevertheless are fewer and more universal and bestow a deeper comprehension of things, because of the efficaciousness of the intellectual power of such natures: whereas the inferior intellectual natures possess a greater number of species, which are less universal, and bestow a lower degree of comprehension, in proportion as they recede from the intellectual power of the higher natures. If, therefore, the inferior substances received species in the same degree of universality as the superior substances, since they are not so strong in understanding, the knowledge which they would derive through them would be imperfect, and of a general and confused nature. We can see this to a certain extent in man, for those who are of weaker intellect fail to acquire perfect knowledge through the universal conceptions of those who have a better understanding, unless things are explained to them singly and in detail. 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 be confused and general. 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.

It is clear then that it was for the soul's good that it was united to a body, and that it understands by turning to the phantasms. Nevertheless it is possible for it to exist apart from the body, and also to understand in another way.

Reply to Objection 1: The Philosopher's words carefully examined will show that he said this on the previous supposition that understanding is a movement of body and soul as united, just as sensation is, for he had not as yet explained the difference between intellect and sense. We may also say that he is referring to the way of understanding by turning to phantasms. This is also the meaning of the second objection.

Reply to Objection 3: The separated soul does not understand by way of innate species, nor by species abstracted then, nor only by species retained, and this the objection proves; 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. 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.

Objection 1: It would seem that the separated soul does not understand separate substances. For the soul is more perfect when joined to the body than when existing apart from it, being an essential part of human nature; and every part of a whole is more perfect when it exists in that whole. But the soul in the body does not understand separate substances as shown above (Question [88], Article [1]). Therefore much less is it able to do so when apart from the body.

Objection 2: Further, whatever is known is known either by its presence or by its species. But separate substances cannot be known to the soul by their presence, for God alone can enter into the soul; nor by means of species abstracted by the soul from an angel, for an angel is more simple than a soul. Therefore the separated soul cannot at all understand separate substances.

Objection 3: Further, some philosophers said that the ultimate happiness of man consists in the knowledge of separate substances. If, therefore, the separated soul can understand separate substances, its happiness would be secured by its separation alone; which cannot be reasonably be said.

On the contrary, Souls apart from the body know other separated souls; as we see in the case of the rich man in hell, who saw Lazarus and Abraham (Lk. 16:23). Therefore separated souls see the devils and the angels.

I answer that, Augustine says (De Trin. ix, 3), "our mind acquires the knowledge of incorporeal things by itself"---i.e. by knowing itself (Question [88], Article [1], ad 1). Therefore from the knowledge which the separated soul has of itself, we can judge how it knows other separate things. Now it was said above (Article [1]), that as long as it is united to the body the soul understands by turning to phantasms, and therefore it does not understand itself save through becoming actually intelligent by means of ideas abstracted from phantasms; for thus it understands itself through its own act, as shown above (Question [87], Article [1]). When, however, it is separated from the body, it understands no longer by turning to phantasms, but by turning to simply intelligible objects; hence in that state it understands itself through itself. Now, every separate substance "understands what is above itself and what is below itself, according to the mode of its substance" (De Causis viii): for a thing is understood according as it is in the one who understands; while one thing is in another according to the nature of that in which it is. And the mode of existence of a separated soul is inferior to that of an angel, but is the same as that of other separated souls. Therefore the soul apart from the body has perfect knowledge of other separated souls, but it has an imperfect and defective knowledge of the angels so far as its natural knowledge is concerned. But the knowledge of glory is otherwise.

Reply to Objection 1: The separated soul is, indeed, less perfect considering its nature in which it communicates with the nature of the body: but it has a greater freedom of intelligence, since the weight and care of the body is a clog upon the clearness of its intelligence in the present life.

Reply to Objection 2: The separated soul understands the angels by means of divinely impressed ideas; which, however, fail to give perfect knowledge of them, forasmuch as the nature of the soul is inferior to that of an angel.

Reply to Objection 3: Man's ultimate happiness consists not in the knowledge of any separate substances; but in the knowledge of God, Who is seen only by grace. The knowledge of other separate substances if perfectly understood gives great happiness---not final and ultimate happiness. But the separated soul does not understand them perfectly, as was shown above in this article.

Objection 1: It would seem that the separated soul knows all natural things. For the types of all natural things exist in separate substances. Therefore, as separated souls know separate substances, they also know all natural things.

Objection 2: Further, whoever understands the greater intelligible, will be able much more to understand the lesser intelligible. But the separated soul understands immaterial substances, which are in the highest degree of intelligibility. Therefore much more can it understand all natural things which are in a lower degree of intelligibility.

On the contrary, The devils have greater natural knowledge than the separated soul; yet they do not know all natural things, but have to learn many things by long experience, as Isidore says (De Summo Bono i). Therefore neither can the separated soul know all natural things.

I answer that, As stated above (Article [1]), the separated soul, like the angels, understands by means of species, received from the influence of the Divine light. Nevertheless, as the soul by nature is inferior to an angel, to whom this kind of knowledge is natural, the soul apart from the body through such species does not receive perfect knowledge, but only a general and confused kind of knowledge. Separated souls, therefore, have the same relation through such species to imperfect and confused knowledge of natural things as the angels have to the perfect knowledge thereof. Now angels through such species know all natural things perfectly; because all that God has produced in the respective natures of natural things has been produced by Him in the angelic intelligence, as Augustine says (Gen. ad lit. ii, 8). Hence it follows that separated souls know all natural things not with a certain and proper knowledge, but in a general and confused manner.

Reply to Objection 1: Even an angel does not understand all natural things through his substance, but through certain species, as stated above (Question [87], Article [1]). So it does not follow that the soul knows all natural things because it knows separate substances after a fashion.

Reply to Objection 2: As the soul separated from the body does not perfectly understand separate substances, so neither does it know all natural things perfectly; but it knows them confusedly, as above explained in this article.

Reply to Objection 3: Isidore speaks of the knowledge of the future which neither angels, nor demons, nor separated souls, know except so far as future things pre-exist in their causes or are known by Divine revelation. But we are here treating of the knowledge of natural things.

Reply to Objection 4: Knowledge acquired here by study is proper and perfect; the knowledge of which we speak is confused. Hence it does not follow that to study in order to learn is useless.

Objection 1: It would seem that the separated soul does not know singulars. For no cognitive power besides the intellect remains in the separated soul, as is clear from what has been said above (Question [77], Article [8]). But the intellect cannot know singulars, as we have shown (Question [86], Article [1]). Therefore the separated soul cannot know singulars.

Objection 2: Further, the knowledge of the singular is more determinate than knowledge of the universal. But the separated soul has no determinate knowledge of the species of natural things, therefore much less can it know singulars.

Objection 3: Further, if it knew the singulars, yet not by sense, for the same reason it would know all singulars. But it does not know all singulars. Therefore it knows none.

On the contrary, The rich man in hell said: "I have five brethren" (Lk. 16:28).

I answer that, Separated souls know some singulars, but not all, not even all present singulars. To understand this, we must consider that there is a twofold way of knowing things, one by means of abstraction from phantasms, and in this way singulars cannot be directly known by the intellect, but only indirectly, as stated above (Question [86], Article [1]). The other way of understanding is by the infusion of species by God, and in that way it is possible for the intellect to know singulars. For as God knows all things, universal and singular, by His Essence, as the cause of universal and individual principles (Question [14], Article [2]), so likewise separate substances can know singulars by species which are a kind of participated similitude of the Divine Essence. There is a difference, however, between angels and separated souls in the fact that through these species the angels have a perfect and proper knowledge of things; whereas separated have only a confused knowledge. Hence the angels, by reason of their perfect intellect, through these species, know not only the specific natures of things, but also the singulars contained in those species; whereas separated souls by these species know only those singulars to which they are determined by former knowledge in this life, or by some affection, or by natural aptitude, or by the disposition of the Divine order; because whatever is received into anything is conditioned according to the mode of the recipient.

Reply to Objection 1: The intellect does not know the singular by way of abstraction; neither does the separated soul know it thus; but as explained above.

Reply to Objection 2: The knowledge of the separated soul is confined to those species or individuals to which the soul has some kind of determinate relation, as we have said.

Reply to Objection 3: The separated soul has not the same relation to all singulars, but one relation to some, and another to others. Therefore there is not the same reason why it should know all singulars.

Objection 1: It would seem that the habit of knowledge acquired in this life does not remain in the soul separated from the body: for the Apostle says: "Knowledge shall be destroyed" (1 Cor. 13:8).

Objection 2: Further, some in this world who are less good enjoy knowledge denied to others who are better. If, therefore, the habit of knowledge remained in the soul after death, it would follow that some who are less good would, even in the future life, excel some who are better; which seems unreasonable.

Objection 3: Further, separated souls will possess knowledge by influence of the Divine light. Supposing, therefore, that knowledge here acquired remained in the separated soul, it would follow that two forms of the same species would co-exist in the same subject which cannot be.

Objection 4: Further, the Philosopher says (Praedic. vi, 4,5), that "a habit is a quality hard to remove: yet sometimes knowledge is destroyed by sickness or the like." But in this life there is no change so thorough as death. Therefore it seems that the habit of knowledge is destroyed by death.

On the contrary, Jerome says (Ep. liii, ad Paulinum), "Let us learn on earth that kind of knowledge which will remain with us in heaven."

I answer that, Some say that the habit of knowledge resides not in the intellect itself, but in the sensitive powers, namely, the imaginative, cogitative, and memorative, and that the intelligible species are not kept in the passive intellect. If this were true, it would follow that when the body is destroyed by death, knowledge here acquired would also be entirely destroyed.

But, since knowledge resides in the intellect, which is "the abode of species," as the Philosopher says (De Anima iii, 4), the habit of knowledge here acquired must be partly in the aforesaid sensitive powers and partly in the intellect. This can be seen by considering the very actions from which knowledge arises. For "habits are like the actions whereby they are acquired" (Ethic. ii, 1). Now the actions of the intellect, by which knowledge is here acquired, are performed by the mind turning to the phantasms in the aforesaid sensitive powers. Hence through such acts the passive intellect acquires a certain facility in considering the species received: and the aforesaid sensitive powers acquire a certain aptitude in seconding the action of the intellect when it turns to them to consider the intelligible object. But as the intellectual act resides chiefly and formally in the intellect itself, whilst it resides materially and dispositively in the inferior powers, the same distinction is to be applied to habit.

Knowledge, therefore, acquired in the present life does not remain in the separated soul, as regards what belongs to the sensitive powers; but as regards what belongs to the intellect itself, it must remain; because, as the Philosopher says (De Long. et Brev. Vitae ii), a form may be corrupted in two ways; first, directly, when corrupted by its contrary, as heat, by cold; and secondly, indirectly, when its subject is corrupted. Now it is evident that human knowledge is not corrupted through corruption of the subject, for the intellect is an incorruptible faculty, as above stated (Question [79], Article [2], ad 2). Neither can the intelligible species in the passive intellect be corrupted by their contrary; for there is no contrary to intelligible "intentions," above all as regards simple intelligence of "what a thing is." But contrariety may exist in the intellect as regards mental composition and division, or also reasoning; so far as what is false in statement or argument is contrary to truth. And thus knowledge may be corrupted by its contrary when a false argument seduces anyone from the knowledge of truth. For this reason the Philosopher in the above work mentions two ways in which knowledge is corrupted directly: namely, "forgetfulness" on the part of the memorative power, and "deception" on the part of a false argument. But these have no place in the separated soul. Therefore we must conclude that the habit of knowledge, so far as it is in the intellect, remains in the separated soul.

Reply to Objection 1: The Apostle is not speaking of knowledge as a habit, but as to the act of knowing; and hence he says, in proof of the assertion quoted, "Now, I know in part."

Reply to Objection 2: As a less good man may exceed a better man in bodily stature, so the same kind of man may have a habit of knowledge in the future life which a better man may not have. Such knowledge, however, cannot be compared with the other prerogatives enjoyed by the better man.

Reply to Objection 3: These two kinds of knowledge are not of the same species, so there is no impossibility.

Reply to Objection 4: This objection considers the corruption of knowledge on the part of the sensitive powers.

Objection 1: It would seem that the act of knowledge here acquired does not remain in the separated soul. For the Philosopher says (De Anima i, 4), that when the body is corrupted, "the soul neither remembers nor loves." But to consider what is previously known is an act of memory. Therefore the separated soul cannot retain an act of knowledge here acquired.

Objection 2: Further, intelligible species cannot have greater power in the separated soul than they have in the soul united to the body. But in this life we cannot understand by intelligible species without turning to phantasms, as shown above (Question [84], Article [7]). Therefore the separated soul cannot do so, and thus it cannot understand at all by intelligible species acquired in this life.

Objection 3: Further, the Philosopher says (Ethic. ii, 1), that "habits produce acts similar to those whereby they are acquired." But the habit of knowledge is acquired here by acts of the intellect turning to phantasms: therefore it cannot produce any other acts. These acts, however, are not adapted to the separated soul. Therefore the soul in the state of separation cannot produce any act of knowledge acquired in this life.

On the contrary, It was said to Dives in hell (Lk. 16:25): "Remember thou didst receive good things in thy lifetime."

I answer that, Action offers two things for our consideration---its species and its mode. Its species comes from the object, whereto the faculty of knowledge is directed by the (intelligible) species, which is the object's similitude; whereas the mode is gathered from the power of the agent. Thus that a person see a stone is due to the species of the stone in his eye; but that he see it clearly, is due to the eye's visual power. Therefore as the intelligible species remain in the separated soul, as stated above (Article [5]), and since the state of the separated soul is not the same as it is in this life, it follows that through the intelligible species acquired in this life the soul apart from the body can understand what it understood formerly, but in a different way; not by turning to phantasms, but by a mode suited to a soul existing apart from the body. Thus the act of knowledge here acquired remains in the separated soul, but in a different way.

Reply to Objection 1: The Philosopher speaks of remembrance, according as memory belongs to the sensitive part, but not as belonging in a way to the intellect, as explained above (Question [79], Article [6]).

Reply to Objection 2: The different mode of intelligence is produced by the different state of the intelligent soul; not by diversity of species.

Reply to Objection 3: The acts which produce a habit are like the acts caused by that habit, in species, but not in mode. For example, to do just things, but not justly, that is, pleasurably, causes the habit of political justice, whereby we act pleasurably. (Cf. Aristotle, Ethic. v, 8: Magn. Moral. i, 34).

Objection 1: It would seem that local distance impedes the separated soul's knowledge. For Augustine says (De Cura pro Mort. xiii), that "the souls of the dead are where they cannot know what is done here." But they know what is done among themselves. Therefore local distance impedes the knowledge in the separated soul.

Objection 2: Further, Augustine says (De Divin. Daemon. iii), that "the demon's rapidity of movement enables them to tell things unknown to us." But agility of movement would be useless in that respect unless their knowledge was impeded by local distance; which, therefore, is a much greater hindrance to the knowledge of the separated soul, whose nature is inferior to the demon's.

Objection 3: Further, as there is distance of place, so is there distance of time. But distance of time impedes knowledge in the separated soul, for the soul is ignorant of the future. Therefore it seems that distance of place also impedes its knowledge.

On the contrary, It is written (Lk. 16:23), that Dives, "lifting up his eyes when he was in torment, saw Abraham afar off." Therefore local distance does not impede knowledge in the separated soul.

I answer that, Some have held that the separated soul knows the singular by abstraction from the sensible. If that were so, it might be that local distance would impede its knowledge; for either the sensible would need to act upon the soul, or the soul upon the sensible, and in either case a determinate distance would be necessary. This is, however, impossible because abstraction of the species from the sensible is done through the senses and other sensible faculties which do not remain actually in the soul apart from the body. But the soul when separated understands singulars by species derived from the Divine light, which is indifferent to what is near or distant. Hence knowledge in the separated soul is not hindered by local distance.

Reply to Objection 1: Augustine says that the souls of the departed cannot see what is done here, not because they are 'there,' as if impeded by local distance; but for some other cause, as we shall explain (Article [8]).

Reply to Objection 2: Augustine speaks there in accordance with the opinion that demons have bodies naturally united to them, and so have sensitive powers, which require local distance. In the same book he expressly sets down this opinion, though apparently rather by way of narration than of assertion, as we may gather from De Civ. Dei xxi, 10.

Reply to Objection 3: The future, which is distant in time, does not actually exist, and therefore is not knowable in itself, because so far as a thing falls short of being, so far does it fall short of being knowable. But what is locally distant exists actually, and is knowable in itself. Hence we cannot argue from distance of time to distance of place.

Objection 1: It would seem that separated souls know what takes place on earth; for otherwise they would have no care for it, as they have, according to what Dives said (Lk. 16:27,28), "I have five brethren . . . he may testify unto them, lest they also come into the place of torments." Therefore separated souls know what passes on earth.

Objection 2: Further, the dead often appear to the living, asleep or awake, and tell them of what takes place there; as Samuel appeared to Saul (1 Kgs. 28:11). But this could not be unless they knew what takes place here. Therefore they know what takes place on earth.

Objection 3: Further, separated souls know what happens among themselves. If, therefore, they do not know what takes place among us, it must be by reason of local distance; which has been shown to be false (Article [7]).

On the contrary, It is written (Job 14:21): "He will not understand whether his children come to honor or dishonor."

I answer that, By natural knowledge, of which we are treating now, the souls of the dead do not know what passes on earth. This follows from what has been laid down (Article [4]), since the separated soul has knowledge of singulars, by being in a way determined to them, either by some vestige of previous knowledge or affection, or by the Divine order. Now the souls departed are in a state of separation from the living, both by Divine order and by their mode of existence, whilst they are joined to the world of incorporeal spiritual substances; and hence they are ignorant of what goes on among us. Whereof Gregory gives the reason thus: "The dead do not know how the living act, for the life of the spirit is far from the life of the flesh; and so, as corporeal things differ from incorporeal in genus, so they are distinct in knowledge" (Moral. xii). Augustine seems to say the same (De Cura pro Mort. xiii), when he asserts that, "the souls of the dead have no concern in the affairs of the living."

Gregory and Augustine, however, seem to be divided in opinion as regards the souls of the blessed in heaven, for Gregory continues the passage above quoted: "The case of the holy souls is different, for since they see the light of Almighty God, we cannot believe that external things are unknown to them." But Augustine (De Cura pro Mort. xiii) expressly says: "The dead, even the saints do not know what is done by the living or by their own children," as a gloss quotes on the text, "Abraham hath not known us" (Is. 63:16). He confirms this opinion by saying that he was not visited, nor consoled in sorrow by his mother, as when she was alive; and he could not think it possible that she was less kind when in a happier state; and again by the fact that the Lord promised to king Josias that he should die, lest he should see his people's afflictions (4 Kgs. 22:20). Yet Augustine says this in doubt; and premises, "Let every one take, as he pleases, what I say." Gregory, on the other hand, is positive, since he says, "We cannot believe." His opinion, indeed, seems to be the more probable one---that the souls of the blessed who see God do know all that passes here. For they are equal to the angels, of whom Augustine says that they know what happens among those living on earth. But as the souls of the blessed are most perfectly united to Divine justice, they do not suffer from sorrow, nor do they interfere in mundane affairs, except in accordance with Divine justice.

Reply to Objection 1: The souls of the departed may care for the living, even if ignorant of their state; just as we care for the dead by pouring forth prayer on their behalf, though we are ignorant of their state. Moreover, the affairs of the living can be made known to them not immediately, but the souls who pass hence thither, or by angels and demons, or even by "the revelation of the Holy Ghost," as Augustine says in the same book.

Reply to Objection 2: That the dead appear to the living in any way whatever is either by the special dispensation of God; in order that the souls of the dead may interfere in affairs of the living---and this is to be accounted as miraculous. Or else such apparitions occur through the instrumentality of bad or good angels, without the knowledge of the departed; as may likewise happen when the living appear, without their own knowledge, to others living, as Augustine says in the same book. And so it may be said of Samuel that he appeared through Divine revelation; according to Ecclus. 46:23, "he slept, and told the king the end of his life." Or, again, this apparition was procured by the demons; unless, indeed, the authority of Ecclesiasticus be set aside through not being received by the Jews as canonical Scripture.

Reply to Objection 3: This kind of ignorance does not proceed from the obstacle of local distance, but from the cause mentioned above.