This is the part three of a series of articles related to the Greek Presocratic Philosophers. The Presocratics were a wide and varied group of philosopher-scientists active between the years 585 BC and 400 BC. The inquiries that the Presocratics conducted into the nature of reality established the scope and general structure of philosophical inquiry even up until the present day. This article will mainly focus on Anaximenes, the last of the Milesian “physicists.”

Out of the three Milesian philosophers, Anaximenes usually doesn’t get as much attention paid to him.  Actually, I feel like he kind of just gets lost in the shuffle, but it is very apparent when one searches through the available scholarly material that there just doesn’t seem to be as much interest in Anaximenes as Thales or Anaximander. He was active after Anaximander and the fragmentary evidence clearly shows an attempt to continue the line of inquiry begun by his predecessors.  Anaximenes was still concerned with attempting to identify what the underlying principle (the ἀρχή)  of reality was, and to build an explanation of the process of change that is observable within φύσις (phusis), that is, reality as a whole.  But something interesting occurs in Anaximenes’ inquiry that distinguishes him from  Anaximander.  And it isn’t just that Anaximenes ‘reverts’ back to a non-metaphysical explanatory model of the operations that govern reality, although that is also very important.  The interesting thing about Anaximenes, as far as I see it, is that we actually start to get a somewhat early prototypical sense of the concept of οὐσία (ousia), a term commonly translated in English as ‘substance.’ 

Primitive Substance

When we had looked at Thales, we had seen that, in attempting to answer the question concerning the origin of the world, and the question of how the world operated, he was clearly indebted to the early Greek poetical tradition which presupposed a primordial generative divinity underlying every observable φαινόμενον (phenomenon).  Thales had taken this idea and, using an early proto-scientific inferential method, transformed it into a theory of genesis in which  ὕδωρ (hudor), what can be vaguely translated as ‘water,’ was the ἀρχή which was responsible for the generation of the world.  The world was not ‘created’ it was ‘born’ or ’emerged’ from out of ὕδωρ which was the precondition for life. But we don’t have much else preserved from Thales’ words, and it is very difficult to ascribe to Thales any other explicit views regarding ‘how’ the world is supposed to operate. 

In fact, it’s very difficult to tell whether Thales thought that ὕδωρ was something that substantially changed along with appearances, or, ultimately remained itself, only externally taking on the ‘qualities’ of things.  For example, if Thales thought of ὕδωρ as something that substantially changed into some observable thing, then, an everyday object like a chair could really be said to be made of wood, as our immediate perception would normally tell us.  The wood ‘material’ perhaps started as ὕδωρ, but through some process, had ‘substantially’ changed into wood.  So, ὕδωρ could not be said to be present any longer in the observable φαινόμενον before us, the appearance of a chair.  Any qualities belonging to ὕδωρ were now gone, replaced by qualities belonging to a chair, qualities which could all be completely contrary to what had been present at an earlier time.

This interpretation broadly aligns with how Anaximander approached his own inquiry into the nature of reality.  Anaximander thought that the φαινόμενον which we were privy to consisted only of alternating qualities, such as hot and cold, which were being shuffled into and out of the light of φύσις  by the meta-physical necessity imposed by δίκη (dike).  Ultimately, all qualities (essentially all observable things which they constituted as well) could be placed under the category of ‘determined,’ and, this being the case, Anaximander thought, the only remaining principle one could postulate would be the ἄπειρον (apeiron), the undetermined, or infinitely limitless.  

Or perhaps we could interpret Thales the following way:  perhaps we can think of ὕδωρ as that which remains hidden beneath the appearance of a chair.  It never really changes, only appears to change. The chair seems like wood to us, all of our perceptions tell us it is a hard solid thing unlike anything we would suppose ὕδωρ (in all of it’s variations we have encountered) to be, but that is only the ‘look’ that ὕδωρ has taken on, through some outer process of change whereby ὕδωρ is altered or reorganized enough so that it appears differently while still essentially preserving itself.

When we think of the ἀρχή in this way, we are thinking of it in ‘substantial’ terms.  The ἀρχή is a substance, or, οὐσία, an underlying irreducible thing which fundamentally remains itself, but has its outward phenomenality altered in some way.  Its attributable qualities change from one kind to another, but they are modifications that have no bearing on the underlying thing.  The underlying thing still has a determinate essential nature to it, it is not a blank thing in itself, and what we are privy to when observing it are only accidental features belonging to that thing, features that can and most likely will change at some point in time. To be clear, the concept of οὐσία still had a few hundred years to be definitively articulated by Aristotle, but we begin to catch vague glimpses of it in Anaximenes, although in a very rudimentary form and lacking in the precise technical language that Aristotle subsequently develops in his own inquiries about the nature of reality.

Despite this, Anaximenes was able to put forward an explanatory model of the process of observable change in the world by postulating that any observable φαινόμενον was fundamentally reducible to a determinate thing, ἀήρ (aer). And it was this ἀήρ which supported reality and also took on different forms as it was acted upon by worldly forces. But what was this ἀήρ which remained itself yet constituted the material from which everything else was composed of?

What is ἀήρ ?

The closest English words that approximates ἀήρ are ‘air,’ ‘mist,’ or ‘wind.’ Once, again, as I have been doing all throughout this study of the Milesian philosophers, I am choosing to keep the Greek spelling in order to highlight the strangeness of the word ἀήρ and how it doesn’t quite fit into our own modern sensibilities. When we think of ‘air’ or ‘wind’ for example, we are typically thinking of thin transparent atmospheric phenomena. This was also how Aristotle and many of the Greek philosophers following Anaximenes mistakenly characterized ἀήρ. If we think of ἀήρ in this way, the idea that it could be anything like an originating principle of the cosmos seems odd. How can the world come to be from something which seems so ‘insubstantial?’ The word ‘mist’ gets us a little bit closer (it seems slightly more substantial), but once again, our modern sensibilities tell us that mist is just tiny droplets of water and the idea that tiny droplets of water are able to come together to form complex structures like planets and mountains, and even human bodies just does not sit right with us. Our modern way of thinking tells us that there are other elements involved in the construction of these sorts of things, it can’t just be tiny droplets of water. So, once again, the word ‘mist’ doesn’t quite capture what is meant by the word ἀήρ.

But the Milesians did not have our modern sensibilities available to them. As I pointed out in my article on Thales, found here, for the early Greeks, it was simply taken as a given that the world which we were privy to, as human beings, was only an appearance which also hid a primordial divinity constantly at play beneath it. These divine forces were not necessarily divorced from the world either, they were very much imbedded and primordially engaged in a constant cycle of birth and emergence which the Greeks, at this stage in their thought, supposed characterized φύσις as a whole. Thales and Anaximander attempted to make sense of this picture of reality using pre-scientific inferential methods, but their overall outlooks were still colored by the Hesiodic and Homeric poetical traditions which preceded them. So, to get a clearer idea of how Anaximenes probably thought about ἀήρ, it might be helpful as well to look backwards at uses of the word ἀήρ in the early Greek tradition.

Homer, in the Iliad, described ἀήρ as a dark moving and obscuring cloud of divine origin which the god Zeus employed to cover over battlefields. (Iliad 17.269). Anaximander, Anaximenes’ immediate predecessor, also spoke of ἀήρ, describing it as a dark and misty cloud produced during the early stages of the emergence of the cosmos, when contrary qualities first became determined, when previously, all had been undetermined and without any definite characteristics. (Plut. Strom. 2; Dox. 579). From these two sources, we can already begin to see an interesting notion associated with ἀήρ, namely, that it is in close proximity to the divine. In Homer, ἀήρ is a visible manifestation of the will of the gods, it is a tool, an instrument of their power, an obscuring φαινόμενον (phenomenon) through which they paradoxically show themselves and make themselves present (in their hiddenness) to human eyes.

In Anaximander’s cosmogony (story of cosmic genesis), ἀήρ, as it blooms, is as close to the divine ἄπειρον (apeiron) as it gets, spewing forth from out of the very first violent moments of the emergence of reality. Furthermore, in both Homer and Anaximander’s descriptions of ἀήρ, it is also closely associated with movement and violence, which, for the early Greeks, was the hallmark of life. On Anaximander’s view, it was the violent movement of contradictory qualities fighting to stay in the light of φύσις that sustained existence as a whole, and for Homer, it was the violent movement of soldiers slaughtering each other for immortal glory that gave life meaning and direction.

Anaximenes seems to have agreed with Homer and Anaximenes, that this violent moving obscure mass was not only in close proximity to the divine, but furthermore, that it was also a primordially determined thing, that if one could say anything about ἀήρ, not only that it was that ἀήρ was there at the beginning, when reality was still in its infancy, but it was there at the beginning already as itself (determined as a some-thing). Anaximenes seems to have thought that it was too much to suppose a meta-physical origin to ἀήρ, that is, an origin beyond the realm of φύσις. (Theophrastos; Simpl. Phys. 6r 24, 26; Dox. 476). After all, if ἀήρ was one of the earliest determinate ‘things’ that one could postulate, and one could derive the origins of other elements of reality through ἀήρ, then what need was there to keep looking further beyond ἀήρ?

For Anaximenes then, ἀήρ was the divine source of life from which everything, including the gods, emerged: “[Anaximander] said, the things that are, and have been, and shall be, the gods and things divine, took their rise, while other things come from its [ἀήρ] offspring.” (Hippolytus, Refutations. i. 7). This picture of ἀήρ as a generative principle also lines up with how the poetical traditions that preceded the Milesian philosophers conceived of φύσις as fundamentally alive in the biological sense. In fact, that is why Anaximenes seemed to think that ἀήρ was just another word for ‘soul.’ It was the soul, or breath of the world, so why shouldn’t it also be the breath that resides in the human being?

So, for Anaximenes, when it came to identifying the principle from which all of reality originated, there doesn’t seem to have been a need to go further backwards in the cosmic timeline towards some meta-physical origin. One could name a determinate substantial thing, ἀήρ, conceived of as a divine moving violent misty wind, as the original material and still successfully form an explanatory model of the cosmos, and this is very much how Anaximenes proceeded. In fact, for Anaximenes, everything, even the whole earth, rode on this cosmic wind. I want to note that I do deviate from Anaximenes’ ancient commentators who supposed that ἀήρ in its primordial form was invisible. I think there is ample evidence, based on textual analysis of how Anaximenes’ predecessors conceived of ἀήρ to suppose that he also thought of it as being primordially obscure.

Additionally, this obscuring aspect of ἀήρ seems more in line with another way that the Milesian philosophers supposed φύσις to be at its most fundamental level, as that which was always essentially hidden to some degree from human observation. This isn’t to say that Anaximenes would have denied that ἀήρ could also be invisible or transparent, but I think that he would have held that ἀήρ only did so after being further worked upon by external forces, as we will see in the next section in which I will discuss how Anaximenes explained the mechanism by which ἀήρ remained what it was and still constituted all of the other objects which human beings observed in the world.

The Process of Change

Anaximenes did not deny that there were mountains, trees, oceans, human beings, animals, and all of the other objects that we observe in the world. Anaximenes also didn’t deny that change was a feature of observable reality. Things grew and transformed, landmasses expanded and shrank, planets and other celestial bodies came into and out of being. But Anaximenes did hold that all of these things were simply ἀήρ which substantially remained itself but had still been worked upon by the forces of μάνωσις (manosis) and πυκνωσις (pyknosis) which shaped ἀήρ into what Anaximenes would have recognized as the basic sorts of things that constitute the observable world.

The word μάνωσις is usually translated into English as rarefaction, but it also has the less technical connotation of a making loose, or making something porous. The word πυκνωσις is also usually translated as condensation, but can also more easily be understood as a process of densification or compacting wherein the parts of a whole come closer together. With this in mind, we can see that Anaximenes did not think that there was a need to posit a meta-physical force like Anaximander’s δίκη (dike) to work upon the things of this world.

Anaximenes had recourse to what was an observable φαινόμενον that human beings saw day in and day out when they saw water turn to steam, or rain clouds give way to rain. μάνωσις and πυκνωσις were always noticed, and recognized, as forces that operated upon the world. Furthermore, they were not forces that were only at the disposal of divinities, of the gods. A human being could effect change on materials by applying those same forces on them, such as when one boiled water. So, Anaximenes’ proposed forces of change were not ‘hidden’ behind the appearance of the world, they were very much a part of it and observable to a higher degree than Anaximander’s δίκη.

Anaximenes also thought, in postulating the forces of μάνωσις and πυκνωσις , that he could reasonably account for the wide range in diversity of observable things and for the change and alteration that seemed to be the way of all beings. If ἀήρ was the primordial principle which stayed itself yet was in everything, then it needed to be altered in some such way that it still retained its identity as ἀήρ despite the changes that it underwent. Whatever force was postulated that enacted change on ἀήρ would also need to be such that it would not seemingly destroy ἀήρ either. But this could only be possible if ἀήρ itself was only moved, sometimes closer together, sometimes further apart without any part of it being substantially destroyed.

So, on the basis of the force of πυκνωσις for example, Anaximenes could argue that, in becoming denser and also heavier, ἀήρ could turn into clouds which, under further pressure, would turn into water and finally into rain. Similarly, if I were to heat water in a kettle, the force of μάνωσις would loosen and make the ἀήρ in the form of water so thin that it would transform into steam and finally transparent air. On Anaximenes’ picture too, air could, if heated sufficiently through the process of diffusion, even transform into fire. The figure below (fig. 1) illustrates the ontology of ‘things’ that Anaximenes was said to be able to account for in his system. Notice also that contrary ‘qualities’ of the sort that Anaximander spoke of, like hot and cold, could also be explained away, as qualities that corresponded to ἀήρ when it was either in a diffused state (hot) or compressed state (cold).

Of course, Anaximenes’ system isn’t comprehensive, much less empirically sound, by our present day scientific standards. But, comparing the theory to the speculations that were forwarded by his predecessors Thales and Anaximander, we can see how Anaximenes was conceptually indebted to and even critical of them. For Anaximenes, Thales had gotten it right that moisture, as a precondition for life, was a feature of whatever divine principle (ἀρχή) the world had originated from. This being the case, ἀήρ possessed moisture as an essential attribute belonging to it. Things that seemed the most ‘alive’ seemed to contain more moisture, while things that intuitively seemed less ‘alive’ like, say, stones, contained less moisture.

Anaximander had attempted to work out a process of change that explained why everyday things didn’t seem like they only consisted of ὕδωρ and had ended up proposing principles that were meta-physical, literally outside the realm of φύσις. Anaximenes seemed to think that this was a step too far and that reality could be accounted for by working only with the observable φαινόμενον that one had at their disposable. In this regard, Anaximenes remained within the empirical realm.

My hope is that it has become increasingly clear how extreme the conceptual development was that separated Anaximenes from his predecessors. Anaximenes is really the first of the Milesians that we can call a ‘physicist’ in a more modern way since he appears to have treated φύσις in a much more empirically scientific way than his predecessors. For Anaximenes it was explicitly clear that all of reality was constituted by a single and determinate material ἀήρ which substantially remained itself but was shaped into recognizable things by the forces of μάνωσις and πυκνωσις. He did all of this by deferring to empirical observation (by Ancient Greek standards), with no attempt to posit a meta-physical origin to the things of the world. But of course, the way that Anaximenes developed his theories about reality could only have occurred in the background of the ‘physical’ speculations of his predecessors.

Of course, ‘physical’ as Anaximenes (and all the Milesian philosophers) conceived of it, was a much broader category than we have. It was colored by the mythical poetical tradition that the early Greeks were beholden to, a tradition that allowed for divine forces to be a part of this world in a much more involved and nuanced manner than we might suppose today. But Greek philosophy, in recognizing and building the conceptual language necessary for inquiring about reality, was now on its way towards making a sharp distinction between mythical and logical world-pictures and ultimately, and possibly wrongly, sharper distinctions between the human being and the whole of nature.

One thing I want to point out, in closing out this study of the Milesian philosophers is that, they seemed to take it as a given that φύσις was only accessible to human beings as observable φαινόμενον. At the same time they also supposed that they could make pronouncements about what stood on the other side of seen reality, what was hidden behind appearances, without remotely considering whether the intuitions by which they made their inferences were even adequate for the job. In this regard, the Milesian philosophers were naïve, and that is not meant to discount the advances they made in formulating and conceptualizing how we think about reality, even to the present day.

The Milesian philosophers just simply didn’t have the conceptual tools to criticize their own epistemologies, they merely argued their viewpoints based on their immediate observations with some inferential forays into meta-physical thinking. In a sense, they assumed (possibly wrongly) that knowledge was easily available. It would not be until the latter half of the 6th century that figures like Xenophanes and Heraclitus would begin to question whether knowledge is really such an easily acquired thing, and if it is even possible for human beings to get at it, much less have an understanding of reality as it really is.