Sunday, December 11, 2005

On the Soul and the Afterlife: A Comparison and Contrast Between the Views of Plato and Aristotle

The purpose of this writing is to present a comparison and contrast between the views of Plato and Aristotle on the soul and its relationship to the afterlife. A straightforward manor of procedure will be followed in order to accomplish this task. First, the views of these two ancients on the existence of the soul and its relationship to the body will be presented. Then, a comparison and contrast of the two psychologies will be explored in an effort to search out the pertinent similarities and differences between them. Also, the views of Plato and Aristotle on the relationship of the soul to the afterlife will be analyzed and a further comparison and contrast between the two philosophers presented on the post-life destination of the soul. And, in conclusion, a summary of the information contained in the body of this paper will be provided and a brief mention made of the tremendous influence that Plato and Aristotle have had on the history of philosophy pertaining to the soul and the afterlife.

Plato’s View of the Soul

Plato (427-347 B. C.) was a student of Socrates and was one of the greatest philosophers who ever lived. He is well known for taking much of the philosophical work that was done before his time and developing it, along with his own prolific thoughts, into some of the greatest works ever done in the history of philosophy. One of the topics that he wrote on extensively was the nature and existence of the human soul. In his overall psychology, Plato showed much advancement over the pre-Socratics who reduced the soul merely to air or fire or atoms. Plato was neither a materialist nor epiphenominalist, but an uncompromising spiritualist regarding the soul. And, he held to the doctrine of psychological dualism when it came to the relationship between the soul and the body. Basically, Plato held that the soul and the body were two completely distinct substances that merely interacted with each other during the course of a person’s life. He also held that the soul is man’s most valuable possession, and the true tendance of the soul must be its chief concern. (1) In the Laws (896a 1-2) Plato defines the soul as "self initiating motion" or the "source of motion." This being so, the soul is prior to the body in the sense that it is superior to the body, the latter being moved without being the source of motion, and he also held that the soul must rule the body.(2) Although he often referred to the interacting relationship between the soul and the body of an individual, Plato put a weighty emphasis on the soul as being the prominent aspect of the human being. In fact, Plato held that the soul is actually who a person is and that the soul is basically just trapped in the body, waiting to be released from its material grasp. This is evident in the Laws where Plato states, "What makes each of us to be what we are is only the soul." (XII, 959)

Although Plato does present such a heavy emphases on the soul throughout his writings, he does not deny the influence that may be exercised on the soul by or through the body. In the Republic he includes physical training among the constituents of true education, and he rejects certain types of music because of the deleterious effect they have on the soul. Even though Plato does speak on occasion that the soul merely dwelt in the body and used it, we must not represent him as denying any interaction of soul and body on one another. Plato may not have explained interaction in great detail, but this is a most difficult thing to accomplish in psychology in its own right and it is evident that he at least held to some level of interaction between the substances of soul and body, even though it may have been in a very minimal sense.

All that being said, it will now be useful to go into further detail on some more technical aspects of Plato’s psychology. The most pointed presentation of Plato’s view of the soul can be found in one of his greatest works, the Republic. The basic plan of the Republic is to draw a systematic analogy between the operation of society as a whole and the life of any individual human being. Basically, Plato supposed that people exhibit the same features, preform the same functions, and embody the same virtues that city-states do. Applying the analogy in this way presumes that each of us, like the state, is a complex whole made up of several distinct parts, each of which has its own proper role. Plato argued that there is ample evidence of this in our everyday experience. When faced with choices about what to do, we commonly feel a tug of contrary impulses drawing us in different directions at once, and the most natural explanation for this phenomenon is to distinguish between the distinct elements of ourselves (Republic, 436b).(3)

What is put forth in the Republic is the teaching of the tripartite nature of the soul (Gk. psyche), a doctrine that is said to have been borrowed from the Pythagoreans.(4) According to Plato, there are three kinds of soul.(5) First, there is the rational soul, which he represented as located in the head. Next, there is the spirited soul, which is located in the breast. And, finally, there is the appetitive soul which is located in the abdomen.(6) The first type is immortal and only exists in humans. The second kind is present in brute animals. And, the third kind is present in plants.(7) Furthermore, according to Plato, the rational soul (mind or intellect) is the thinking portion within each of us, which discerns what is real and not merely apparent, judges what is true and what is false, and wisely makes the rational decisions in accordance with which human life is most properly lived. The spirited soul (will or volition), on the other hand, is the active portion; its function is to carry out the dictates of reason in practical life, courageously doing whatever the intellect has determined to do best. And, the appetitive soul (emotion or desire) is the portion of each of us that wants and feels many things, most of which must be deferred in the face of rational pursuits if we are to achieve a salutary degree of self-control. Plato’s analogy in the Republic basically holds that the physical body corresponds to the land, buildings, and other material resources of a city. There is another analogy in the Republic that teaches that the three souls of the human being directly correspond to the three classes of citizen within the state, each of them contributing in its own way to its successful operation.(8)

In the Phaedrus, Plato presented his theory even more graphically, comparing the rational soul to a charioteer whose vehicle is drawn by two horses, one powerful but unruly (desire) and the other disciplined and obedient (will). On Plato’s view, then, a human being is properly said to be just when the three souls preform their proper functions in harmony with each other, working in consonance for the good of the person as a whole–with the rational soul thinking properly (resulting in wisdom); the spirited soul willing what is good (creating courage); and, the appetitive soul feeling in a proper sense (resulting in moderation). Plato’s main intention here is evidently the ethical interest of insisting on the right of the rational element to rule, to act as the charioteer.(9) It is in an analogous sense that this applies to the ethics of Plato and his theory of the just-state. That is, the proper balance of these souls in the individuals of a given state would result in a just-state as a whole. In the very same way that the individual soul is analogous to the just-state, the just-state relates to the particular soul in that an individual man has many different faculties and functions within himself (such as the state contains within its boarders) and it is the harmony of these functions that leads to a virtuous life. A life of virtue is the ultimate goal of Plato’s psychology when it is applied in a practical sense.

Aristotle’s View of the Soul

Aristotle (384-322 B. C.) was a student of Plato and has been of equal magnitude in laying the foundations for the rest of the history of philosophy to build upon. In regards to his emphasis on the study of psychology, Aristotle was adamant to point out the importance of an investigation concerning the soul as he held that it was the vital principle of all living things.(10) Aristotle’s view of the soul stems directly from his view of metaphysics, and he uses his familiar form/matter distinction to answer the question "What is a soul?" At the beginning of De Anima (II.1) he says that there are three sorts of substance that exist, e.g., matter (potentiality), form (actuality), and the compound of matter and form. Aristotle is interested in compounds that are alive and it is these types of compounds, e.g. plants and animals, that are the things that have souls, and, their souls are what make them living things. Furthermore, since form is what makes matter a "this," the soul is the form of a living thing. (Not its shape, but its actuality, that in virtue of which it is the kind of living thing that it is). As Fredrick Copleston explains:

The composite substance, says Aristotle, is a natural body endowed with life, the principle of this body being called the soul. Body cannot be soul, for the body is not life but what has life. . . . The body then, must be as matter to the soul, while the soul is as form or act to the body. Hence Aristotle in his definition of the soul, speaks of it and the entelachy or act of the body that possesses life in potency–‘potentiality of life,’ as he remarks, not referring to a thing which has been dispossessed of soul, but to that which possesses it. The soul is thus the realization of the body and is inseparable from it.(11)

Before moving any further, it will be important to review the general causality of Aristotle in order to better understand the foundations of his psychology. This is due to the fact that the notions of form and matter (which his psychology is based on) are themselves developed within the context of a general theory of causation and explanation which appears in one guise or another in all of Aristotle’s mature works. According to his theory, when we wish to explain what there is to know, for example, about a bronze statue, a complete account consists of at least the following four factors– (1) the statue’s matter, (2) its form or structure, (3) the agent responsible for that matter manifesting its form or structure, and (4) the purpose for which the matter was made to realize that form or structure. These four factors comprise the four causes of Aristotle:

(1) Formal Cause (that by which something comes to be)
(2) Efficient Cause (that through which something comes to be)
(3) Material Cause (that out of which something comes to be)
(4) Final Cause (that for which something comes to be)(12)

The respective applications of these causes to the bronze statue are as follows: (1) its material cause is the bronze itself, (2) its efficient cause is the sculptor, insofar as he forces the bronze into shape, (3) the formal cause is the idea of the completed statue, and (4) the final cause is the idea of the statue as it prompts the sculptor to act on the bronze. With these tenants in mind, the soul is, in accordance with Aristotle’s causality, the cause and principle of the living body insofar as it functions (a) as source of movement, (b) as final cause, and (c) as the real substance (i.e. formal cause) of animate bodies.(13)

Aristotle’s Hylomorphic Soul/Body Unity

So, when Aristotle introduces the soul as the form of the body, and, in turn, that the body is the matter of the soul, he is doing so in a way that would be similar to the relationship of the form of a statue of Hermes made out of certain kind of matter, such as bronze.(14) On this account, although the soul is not a material object, it is not separable from the body. According to Aristotle, " . . . the soul does not exist without the body. For it is not a body, but something which belongs to a body, and for this reason exists in a body, and in a body of such-and-such a kind" (DA. 414a 20ff.). This position held by Aristotle is what is known as Hylomorphism–that the soul and body are one composite substance, or, in other words, one hylomorphic soul/body unity. The word Hylomorphism is simply a compound word composed of the Greek terms for matter (hule) and form or shape (morphe); thus, one could equally describe Aristotle’s view of body and soul as an instance of his "matter-formism." The position of Aristotle on the soul’s relationship to the body is as intrinsic as the relationship between an impression made in wax and the wax itself. In short, one cannot be had without the other. Both body and soul must be present to make up the one substance of an individual person.

Although there is the seemingly undeniable doctrine of an inseparable soul/body unity in Aristotle’s psychology, there are some further considerations that need to be stated in order to understand the full orb of his position and to better compare it with the psychology of Plato (as I intend to do later). As a provision for a fuller understanding of his position, Sir David Ross introduces these following distinctions regarding the "inseparable" nature of soul and body in Aristotle:

. . . the word ‘inseparable’ here needs carful consideration. Soul and Body, like form and matter in general, are in a sense separable. The matter which is now linked with a soul to form a living thing existed before the union began and will exist after it ceases. It is only from form, not from this form, that this matter is inseparable. And again this form can exist apart from this matter. For in Aristotle’s view it is one form that is embodied in all the members of species, and it can exist independently of any one member though not of all. It requires for its existence, therefore, not this matter but this kind of matter. It requires a body with a certain kind of chemical constitution and a certain shape, and it cannot exist embodied in another kind of body.(15)

What Ross is pointing out here opens a window of deeper insight into Aristotle’s psychology. It seems as though Aristotle held that there was a kind of universal unity between the collective form of soulness in general and the totality of the related physical matter as a whole. And, this universal unity was transcendent of the particular soul/body unity that took its particular form/matter existence in individual living things. It’s as though there is a general, universal form/matter unity that finds its nest in the individual soul/body unity of a particular living thing–with the particular, individual soul/body unity being inseparable throughout the finite duration of the living thing and the universal form/matter unity being inseparable for an eternal amount of time.(16) These distinctions put forth by Ross are not only helpful in understanding the deeper metaphysical implications of Aristotle’s psychology, but also bring forth some distinctions that will be helpful in the comparison between Plato and Aristotle on the afterlife.

Grades of Actuality and Potentiality

Based on these foundational aspects of form and matter that comprise the soul/body unity in humans are the more technical aspects of Aristotle’s psychology. These further details are explained in the many distinctions that he puts forth in De Anima regarding various grades of actuality and potentiality that exist within the soul. In his psychology, Aristotle distinguishes between two levels of actuality (Gk. entelechia). He gives knowing and attending as examples of these two kinds of actuality, which have become traditionally referred to as first and second actuality, respectively (DA 412a11). In another place he elaborates this further and adds one more example, that of being asleep vs. being awake (DA 412a22-26), but, he does not fully clarify this important distinction until later on in the De Anima (DA II.5 417a20-30). Furthermore, it is not until even later in the corpus that Aristotle makes further clarification and says that there are different types of both potentiality and actuality, and his explanation concerns different ways in which someone might be described as a knower (DA 417a20).

For example, one might be called a knower in the sense that he or she, (1) is a human being, (2) has grammatical knowledge, and (3) is attending to something. Furthermore, a knower in sense (1) is someone with a mere potential to know something, but no actual knowledge (not everything has this potential, of course, e.g. a rock or an earthworm has no such potential). A knower in sense (2) has some actual knowledge (for example, she may know that it is ungrammatical to say "with John and I"), even though she is not thinking about it right now. And, a knower in sense (3) is actually exercising her knowledge (for example, she thinks "that’s ungrammatical" when she hears someone say "with John and I").(17) It is important to note a key distinction here in that (2) involves both actuality and potentiality. In other words, the knower in the sense (2) actually knows something, but that actual knowledge is itself just a potentiality to think certain thoughts or perform certain actions.(18) So, with that much in focus we can now describe our three knowers in this way–(1) first potentiality, (2) second potentiality (= first actuality), and (3) second actuality.

Here are some illustrations developed by S. Marc Cohen that might help bring further clarification to the distinctions of actuality and potentiality in Aristotle’s view:

(1) First potentiality: A child who does not speak French
(2) Second potentiality (first actuality): A (silent) adult who speaks French (3) Second actuality: An adult speaking (or actively understanding) French

An applicable explanation of these illustrations is as follows: a child (unlike a rock or earthworm) can (learn to) speak french. A Frenchman (unlike a French infant, and unlike most Americans) can actually speak French, even though he is silent for the moment. And, someone who is actually speaking French is, of course, the paradigm case of a French speaker. Aristotle uses this notion of first actuality (the silent french-speaking adult) in his definition of the soul, "The soul is the first actuality of a natural body that is potentially alive" (412a27). Remember that first actuality is a kind of potentiality, or, put another way, it is a capacity to engage in the activity which is corresponding to the second actuality. So, with this in mind, we now understand that a soul is put forth by Aristotle as a capacity of a living thing. But, that being said, the question still remains– the soul is a capacity, "but a capacity to do what?"(19)

In answer to this question, a living thing’s soul is its capacity to engage in the activities that are characteristic of living things of its natural kind. But, yet another question arises, "What are those activities?" In De Anima (II.1; II.2) Aristotle provides some examples, such as: self-nourishment, growth, decay, movement and rest (in respect of place), and perception and intellect. So, according to Aristotle, anything that nourishes itself, that grows, decays, moves about (on its own, not just when moved by something else), perceives, or thinks is alive. And, the capacities of a thing in virtue of which it does these things constitute its soul. In other words, the soul is what is causally responsible for the animate behavior (i.e. the life activities) of a living thing.(20)

It is also important to note that Aristotle posited various degrees of soul in his system of psychology. Basically, there is a nested hierarchy of soul functions or activities (413a23) that give us three corresponding degrees of soul. The hierarchy of soul functions are:

(1) Growth, nutrition, and reproduction
(2) Locomotion and perception
(3) Intellect (= thought)

Additionally, the three corresponding degrees of soul are:

(1) Nutritive soul (plants)
(2) Sensitive soul (all animals)
(3) Rational soul (human beings)

These are nested in the sense that anything that has a higher degree of soul also has all of the lower degrees. All living things grow, nourish themselves, and reproduce. Animals not only do that, but move and perceive. Humans do all of the above and reason as well. There are further subdivisions within the various levels, but this much will suffice for the task at hand. For now, it is just important to remember that the soul is a capacity that enables a life form to perform its necessary actions and functions. The soul is Aristotle’s source of movement in living things.


Overall, it can be said that Aristotle’s view on the soul is somewhat of an empiricist reaction to the rationalism of Plato. I say this in relation to how Plato’s epistemology related to his view on the soul. Plato held that to come to know something through sense perception was to recollect a priori knowledge that was possessed in the pre-existence as a form in the mind. Although it is evident that Aristotle was adhering to similar doctrines of Plato while he was still under his direct influence, it is equally as evident that Aristotle drastically changed his views later on and provided somewhat of a counter argument against Plato’s position.(21) Where Plato posited a priori recollection of eternal forms from the pre-existence, Aristotle, in his mature works, posited a temporal soul/body unity, free of pre-existence, that possessed a tabula rasa (i.e. blank slate) that comes to knowledge through sense perception of the physical world. So, at least at this level, the two philosophers seem to be in diametric opposition to one another.

But, upon further analysis, there appear to be some noteworthy similarities between the psychologies of the two philosophers. First off, neither Plato nor Aristotle were staunch materialists (or functionalists) in their views on the soul. In other words, neither of them denied the existence of souls in human beings by reducing thought to mere functions of matter. They both believed in the existence of souls, and, in the case of humans, that a soul had something to do with ones identity (although Plato put all of identity on the soul, whereas Aristotle did not). Furthermore, they both recognized the importance of studying the existence of the soul and held it as a priority in their philosophical systems. Also, they went to great lengths to delineate different faculties of soul that were of greater and lesser degrees, each recognizing the soul as the source of movement in living things. Although there are some technical differences present, they both show evidence of noticing that there are different degrees of the faculties of soul (e.g. appetites, desires, etc.) present in man and that these faculties were prone to wrestle with one another within the soul. They also both held that it was the ability to reason that set human souls apart from animal and plant souls.

Focusing again on the differences between the two philosophers. Plato was a dualist in that he believed that a human being was comprised of two substances, body and soul, and it was the soul that signified the identity of the particular human. In contrast, Aristotle held that it was a hylomorphic soul/body unity that comprised one substance that signified the individual human being’s identity. Also, Plato believed in the pre-existence of human souls whereas Aristotle (in his mature works) denied such a doctrine. For Plato, the soul was a thing that represented an eternal, pre-existent life form, and, for Aristotle, the soul was only an immaterial, temporal mover of the physical being–there was no such pre-existence. Another related aspect of Plato’s doctrine worth mention here is that of the transmigration of the soul. This is a view held by Plato that is similar to reincarnation–that there are forms of souls that pre-existed in other material things and will go on to exist in other life forms after death. According to Plato, "Every soul may be said to wear out many bodies, especially in the course of a long life" (Phaedo, 87). This was completely denied by Aristotle and will be further addressed later when the comparison/contrast with Plato on the afterlife is drawn.

Plato’s View on the Afterlife

Plato may be said to have begun from a stock of doctrines on immortality that was largely prepared for him by Socrates’ interest in Pythagorean views of the soul. In his earliest depictions of Socrates, Plato makes him espouse an unwavering belief in the existence and immortality of at least some gods and a commitment to the soul’s immortality that is more circumspect and critical but no less profound. These early dialogues contain the ideas that the soul is the true locus of personhood, that its welfare is vastly more important than the body’s welfare, and that at least some part of it survives death. Also present are the views that the soul is judged for its actions, that it may be reincarnated (i.e. transmigration), and, that the post-mortem fate of the soul provides reasons to embrace a life of earthly virtue.(22) These core commitments are also maintained throughout the Platonic corpus, long after the composition of the Apology and Crito. The use of afterlife judgement as a further incentive to virtue, along with the theory of psychic immortality it entails, may be found in the Gorgias, Meno, Phaedo, Phaedrus, Republic, Theaetetus and Laws.(23)
Moreover, what Plato added to the views that were held by Socrates (and the pre-Socratics) was not so much new content as a new ambition–an ambition to prove the soul’s immortality. The majority of the dialogues attributed to his middle period, especially the Phaedo, Phaedrus and Republic, include explicit attempts at such proofs. The Phaedo is devoted to this task almost single-mindedly and is structured as a series of such proofs. Most commentators indicate them as follows:

The Opposites Argument 70a–72e. On the analogy of our experience of various rhythmical processes, such as those of expansion and contraction, sleeping and walking, it is urged that the processes of the universe in general are cyclical, or, as Plato puts it, that ‘opposites’ arise from and give birth to one another. In the case of the ‘opposites’ of death and life, we see in experience only one half of the cycle, the process of dying, by which life gives place to death; but on the grounds of analogy it is reasonable to postulate the existence of a corresponding reverse process by which the dead return again to life. In fact, unless there exists such a reverse process, the ultimate fate of the universe must be the entire cessation of life.(24)

The Recollection Argument 73a–77e. Another case for the immortality of the soul is drawn from an argument that stems directly from Plato’s epistemology–according to which knowledge is really a process of ‘recollection’ of truths of which the mind was familiar with in a previous state of existence. This doctrine, if accepted, proves pre-existence, and thus establishes at least the possibility of continued existence of the disembodied soul after death.(25)

The Resemblance Argument 78b–84b. According to Plato, forms and particulars differ systematically. Forms are invisible, unchanging, uniform and eternal, where particulars are visible, changeable, composite and perishable. The human soul is invisible too, and it investigates Forms without the aid of bodily senses. By ruling a particular body it resembles the divine which rules and leads. Thus the soul is ‘most like the divine, deathless, intelligible, uniform, and indissoluble.’ Its uniformity and partlessness exempt it from the decomposition that destroys compounded bodies; for all these reasons we may conclude that it is immortal.

In addition, the Phaedrus (245) argues for the soul’s immortality from its essence as a self-mover; what acts as an ultimate source of motion for other things cannot have any beginning, or any end. In the Republic X (609–10) Plato adds the argument that each thing can be destroyed only by its own proper evils–as iron by rust, wood by rot or fire and so on–and if the agents that make it worse do not destroy it, nothing else will. But what makes the soul worse is vice, and this has no tendency to destroy the soul. Thus nothing can destroy the soul, and it is imperishable. Furthermore, the Republic X (611) also argues that the soul’s immortality precludes its having parts. Socrates claims that the complex psychology elaborated in the bulk of the Republic applies to the soul only as it is "maimed by its association with the body" in itself, and, when not incarnate, the soul is partless. Immortality is also attributed only to the partless, purely rational soul in the Timaeus (69), where the lower parts are called "mortal." On the evidence of these three dialogues, then, it seems that immortality is a property only of our rational souls. But the myth in the Phaedrus (247–257) and the Republic’s "Myth of Er" tend to suggest that immortal souls still possess irrational parts even when divorced from bodies. This ambivalence over the simplicity or complexity of the discarnate soul became a point of controversy among later Platonists. Regardless, the general intention here has been to show that Plato went to great lengths to argue for the personal immortality of the soul after death.(26)

Aristotle’s View on the Afterlife

Aristotle did not take up the Platonic project of proving the soul’s immortality or of providing eternal rewards for virtuous conduct. Indeed, by defining the soul as the "first actuality of an organic living body" (De Anima II. 1), he seems to have precluded the possibility that any soul can survive the dissolution of the body whose actuality it is. Two lines of thought complicate this story and seem to make room for some immortal element in the soul. The first is the caveat, stated twice (De Anima I.1 II.1), that the continued existence of any part of the soul in separation form the body is impossible, unless there is some activity of the soul that is not a complex activity of the soul and body–thinking is explicitly offered as a possible example of this, in contrast to such activities as feeling fear or anger, which clearly involve psycho-physical cooperation. The second and related complication is that in his analysis of intellect and intellectual thought in De Anima III 4-5 where Aristotle refers to a mind that is "immortal and eternal" and is somehow involved in human thought. If we connect these two strands together, we may conclude that we have found something like the rational part of an individual human being’s soul and that we are being assured of its immortality. However, another line of interpretation will make this immortal and eternal mind (what later tradition calls the active intellect) a force external to the individual, whether a divinity that may be personal in its own right or a reservoir of impersonal thinking power. On views of this sort, what Aristotle is offering us falls short of anything that might be considered to be the personal immortality of individual human souls.(27)

In brief, Aristotle does not make use of the arguments we found in Plato that a certain form of life is to be preferred because of its consequences in the hereafter. There is no promise of eternal rewards for virtue or caution of eternal judgement for evils. It is true that he argues for the superiority of the life of philosophical contemplation on the grounds that the philosopher will most resemble the gods, be dearest to them, and be most likely to earn their favor (NE X 8). But, it must be understood that these benefits belong only to this life and not the next. Also, when this advocacy of contemplation culminates in the call to "be immortal, to the extent possible" by employing our reason, the divine element in us (NE X 7), there is nothing about the afterlife in this appeal, only a striking shift of meaning–immortality has here become removed from survival after death, or eternal existence, and now simply denotes a kind of activity that a participant may share for finite, even fleeting, periods of time.(28)

Further Comparison and Contrast on the Afterlife

Aristotle’s view of the afterlife is so different than Plato’s that it serves, in itself, as a bold contrast. The aspects previously mentioned are obviously in opposition to Plato’s perspectives on the afterlife. For instance, the transmigration of the soul held by Plato has no place in Aristotle’s psychology. Since, in Aristotle, there is no pre-existent soul, and, the soul only exists in its unity with the body, then, the soul is "over with" when the body dies. There is no soul that goes on from this life and appears in another life to possess another body, and so forth. This life would be the end of the line, according to the Aristotelian position, and this serves as a stark contrast to Plato’s view of a disembodied soul after death and its continued transmigrational journey. Nevertheless, even though these glaring differences are there, it is still possible to dig a little deeper and uncover what are perhaps some subtle similarities between the two views. With that in mind, some of the controversies surrounding certain aspects of Plato and Aristotle will serve well as a springboard for some comparative speculation.

Throughout this writing, we have seen that Aristotle generally denies Plato’s doctrine of an immortal soul. But it is important to remember, as was shown earlier, that, in Aristotle’s system, there seemed to be a general form/matter unity between the universal form of the soul and matter which essentially nested in individual (particular) soul/body life forms. As the quote from Sir David Ross pointed out, this universal unity was transcendent of the particular soul/body unity found in individual humans. So, while this is by no means equal to Plato’s doctrine of an immortal soul, there is, at least, a universal composition that transcends the soul/body unity of an individual life form in Aristotle’s view, even though the extent of the transcendency may be confined to the temporal universe. Although it may be a bit of a stretch here, I see this as a slight similarity between the two positions, in that there is at least an element of general transcendence beyond particular physical life forms to be found in the systems of both philosophers (although the level of transcendence is obviously different).

Moreover, it is in the within the realm of some of the controversial aspects of the two psychologies that a further similarity can be sought. Stemming from the superiority of the faculty of reason held by both philosophers, there is an interpretation of certain passages in Aristotle (as mentioned earlier) that suggest that the faculty of reason in humans had an actual, eternal transcendence to it (insofar as it was part of an eternal, universal-thought) and was something that survived death, ultimately residing outside of the physical universe. Although, this continuance of the faculty of reason falls short of the personal immortality of the soul, it still provides a subtly interesting similarity to Plato. For instance, there is the controversial passage that seems to indicate that Plato denied the immortality of the lower souls and held that it was only the rational soul that lived on after death (Timaeus , 69). Setting the controversial issues surrounding this passage aside for the moment, I see this as alluding to a two-fold similarity between Plato and Aristotle in the sense that there is (1) a strong emphasis on the rational faculty of man that is evident in both psychologies, and (2) that this rational element is pushed to the point of transcendence by both philosophers. Once again, the specific details of the transcendence and its extent are different, but, there are certainly aspects that are found to be similar in this strain of analysis. Of course, this is just some interesting speculation on controversial grounds. But, nevertheless, it provides some relevant food for thought and could be further evidence of Plato’s direct influence on Aristotle carried over into his psychology, that is, if such speculations so happen to be sound.


It has been shown throughout this writing that there is much to be compared and contrasted between the views of Plato and Aristotle on the soul and the afterlife. There are times when the both agree on certain tenants, and other times where they are in total disagreement on specific points. There are comparisons between them insofar as they both believed in the existence of the soul and that it was the source of motion in living things; furthermore, they both believed that the soul had different levels, possessing different faculties, and, that the ability to reason was superior to the rest of the lower faculties of the soul. Conversely, there are some stark contrasts that are evident between the two psychologies. Plato held to pre-existent souls and to a dualistic relationship between the two substances of soul and body, and, it was also rather clear at times in his writings that he held to the personal immortality of the soul. Whereas Aristotle denied the pre-existence of souls, held that the soul was an essential part of a single substance (a hylomorphic soul/body unity), and, he put forth no explicit doctrine of personal immortality. Once again regarding comparisons, deeper investigation uncovered some possible, yet subtle, similarities between the two philosophies. These were regarding the evidence of a minimal transcendent element in Aristotle’s view on the soul and how this at least somewhat compares to Plato’s obvious soul-survival doctrine. Also, in accordance with this line of investigation, an emphasis on the rational element of the soul and its relation to the transcendent element appeared to be held by both philosophers.
All of these kinds of similarities and differences between these two magnificents are to be expected, though. The similarities are there because Plato was one of the greatest philosophers who ever lived, and Aristotle was his prized pupil who was directly influenced by him in these specific matters. The differences between them are to be anticipated because Aristotle was a great thinker in his own right, and when he was no longer under Plato’s direct tutelage, he sought to critique, analyze, and develop Plato’s teaching on the soul as well as incorporate many of his own prolific thoughts into the development of his very own psychology. Incredibly, the works on the soul by both of these philosophical giants have greatly influenced the entire history of psychology and the major tenants of their views are held in diverse forms by many philosophers to this very day.

In conclusion, I must say that I do depart from Plato’s substance dualism view of the relationship between the body and soul and that I side with Aristotle on his one substance hylomorphic soul/body unity view. Although, I must add that I find Aristotle’s view on the afterlife as desperately wanting and I at least side with Plato (in a minimal sense) in that I agree there is a personal afterlife in which the individual human soul definitely participates. Although the works on the soul by Plato and Aristotle are very exhaustive and certainly prolific, both of these views as they were presented in their time are worthy of some serious critique and are in need of much further development. This was a task that was brilliantly performed centuries later by Thomas Aquinas, but, the Thomistic syntheses of Plato and Aristotle on the soul is a matter worthy of an entire writing in its own right–perhaps at another time.

1. Frederick Copleston, A History of Philosophy, vol. 1, Greece and Rome: From the Pre-Socratics to Plotinus (New York: Doubleday, 1993), 207.
2. Ibid.
3.Gary Kemerling, Plato: The State and the Soul (Iowa: Philosophy Pages, 2002), 07.
4.Copleston, History of Philosophy, 207.
5.Plato held, in general, that these three "different souls" were not materially different and were intrinsically linked.
6.Joseph Owens, A History of Ancient Western Philosophy (New York: Appleton, Century, Crofts, 1959), 233.
8.Kemerling, The State and the Soul, 07.
9.Copleston, History of Philosophy, 210.
10.Ibid., 325.
11.Ibid., 327.
12.Mortimer J. Adler, Aristotle for Everybody: Difficult Thought Made Easy (New York: Macmillan Publishing Co., Inc.), 42.
13.Copleston, A History of Philosophy, 328.
14.Stanford Encyclopedia of Philosophy. Accessed 11-15-05.
15.Sir David Ross, Aristotle (London: Methuen and Co. LTD, 1964), 132.
16.Aristotle held to the existence of an eternal universe and eternal matter.
17.S. Marc Cohen, Aristotle on the Soul (Washington: University of Washington, 2000), 04.
21.Copelston, A History of Philosophy, 347.
22.Routledge Encyclopedia of Philosophy. Plato, Accessed 11-15-05.
23.Ibid. [The Republic’s vindication of the just life in no way depends on eternal rewards, but after that vindication is complete, book X mentions them as an additional consideration.]
24.A.E. Taylor, The Mind of Plato (Ann Arbor: The University of Michigan Press, 1969), 85.
25.Ibid., 86.
26.It is important to note that Plato almost completely diverted the issue of an afterlife in his later writings. This is probably because he began to see problems fitting the eternal soul in with the rest of his philosophical views.
28. Ibid.

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