The earliest origins of the concept of the soul are hidden in a remote prehistoric past. Human beings undoubtedly lived then, as most still do, in a state of deep absorption in the world around them. This has always made it very difficult to turn attention to whatever it may be about human beings themselves that makes it possible for them to “have a world” at all.
What seems to have struck these early human beings most forcefully was the difference between what is alive and what is dead. This was the distinction that the idea of soul was originally designed to express. The soul was a life-principle, and, as such, it was regarded as something that leaves the body at death. As indicated by a variety of Indo-European words for soul, such as the Sanskrit atman and the Greek psychē, it was often identified with breath; it was not so much immaterial as it was a finer, attenuated form of matter
As thinking about these issues progressed, a variety of functions were assigned to the soul, which gradually came to be conceived as a kind of container in which the functions resided. The soul was what human thoughts and feelings were “in,” and it was itself each person’s inner reality. This connotation of inwardness survives to this day. The soul was considered a distinct individual entity—not unlike an organ of the body, but also very different, because its location in the body could not be determined. Furthermore, the concept of soul seemed familiar because it was spoken of in the way people speak about ordinary “things.” It also appears to have been modeled on familiar objects in the sense that, in perception, every property of an object outside the mind corresponded to a counterpart property within the mind; this was joined by the assumption that the latter somehow reproduced the former. In this way, each soul-mind came to be understood as one more entity in the world, yet one with the unique quality of containing simulacra of the other entities.
One of the facts that the soul-mind was supposed to account for was the knowledge that humans had of the world around them. However oblivious early humans may have been to the notion of themselves as “subjects,” they did not overlook the role that sense organs play in perception. It was sometimes thought—and children still often imagine—that rays of some kind emanate from the eyes and meet other rays emanating from the perceived object halfway, where perception supposedly occurs. Eventually, however, perception came to be understood as a process outside the body that reaches a sense organ and then produces some kind of facsimile of the object in the person whose sense organ has been affected. Knowledge is thus the production of a copy (or something like it) in the mind of the object that is outside it. Just how and where this occurred was unknown, but various parts of the body were usually held to be the locus of both perception and the other functions that were later referred to as “mental.”
The cognitive function thus assigned to the soul could be addressed to many different kinds of objects, and the emphasis given to one or the other of these has varied substantially from one period in the history of thought to another. The natural world was the immediate object of both perception and thought, but it was not long before God came to be considered an even more important object of knowledge. Indeed, knowledge of God eventually came to be regarded by some philosophers as a necessary condition for any other knowledge the soul might have, including that of the natural world. Still another object of knowledge for the soul was the soul itself; its ability to take itself, reflexively, as the object of its own awareness has been cited as one of its most remarkable characteristics.
Of these three types of knowledge—of the external world, of God, and of the soul itself—it is the first that has received most attention from philosophers. Although that priority of interest will be observed in this discussion, the other kinds of knowledge will be touched on in appropriate contexts. (Oddly, one kind of knowledge, of the souls or minds of other human beings, did not become a major topic of philosophical discussion until late in the modern period, and since then it has been much controverted; see other minds, problem of.) But if the soul-mind had all of these different cognitive capabilities, it could not be a purely receptive or passive entity. It had its own spontaneity even in the area of cognition, where it could draw inferences about things or events not immediately present in space or time. Even more important, the soul-mind had the power to make decisions and undertake actions, and accordingly it held responsibility for the moral quality of those decisions and actions. The relation between judgments of the moral quality of action and other so-called “factual” knowledge was also much debated.
The soul in ancient Greece
A great many thinkers have contributed in one way or another to the philosophical understanding of human nature. In the history of Western thought, however, there has been a discernible series of turning points that are of special importance for appreciating the situation of philosophical anthropology at the present time. The first of these occurred in ancient Greece and coincided with the beginning of the Western philosophical tradition. The idea of the soul received its first major philosophical statement in Plato’s tripartite theory of the soul as consisting of reason, spirit, and appetite (see below Plato). A second turning point came in the modern period, between the 17th and 19th centuries, when René Descartes and succeeding philosophers pursued what was later called “the way of ideas” as a means of working out the skeptical possibilities inherent in the models of mind they had inherited from antiquity. They were followed by others who tried to reconstruct the concept of mind on a very different basis. A third such juncture, which occurred in the 19th century but extends into the present, amounted to a full-blown crisis in humankind’s understanding of itself. The significance of this juncture is so central to the viability of philosophical anthropology that further attention must be devoted to it.
In Greek thought, the soul was not conceived in terms of a dualistic contrast with the body, and there was certainly no analogue to the stark Cartesian conception of the mind as “the thing that thinks” amid a natural world of objects defined entirely by their spatial properties. In the thought of Plato and Aristotle, however, there was a clear philosophical conception of the soul as an entity that is somehow distinct from the body and is also the seat of functions like thought, perception, and desire. Because the soul comprised these different functions and because the principal interest of these philosophers was addressed to reason as the one function that made possible an apprehension of the true nature of things, these functions came to be regarded as different “parts” of the soul. Among these, the rational soul—in effect, the mind—was held to be peculiar to human beings, and thus the mind’s efforts to realize its own nature and to resist the distractions of sensation and desire were a primary theme of inquiry. Even so, it has been said with some justice that in the ancient world the soul-mind remained an integral part of the world system; it was not conceived as an independent subject that stood over against the world in the way that “consciousness” has been held to do in the modern period.