2. Ways of Understanding Nature
Before we can explore how nature has been viewed in diverse times and places, we need to know just what the word “nature” refers to in the present context. For example, nature often means that which is not constructed by the artifice of humans; a tree is natural, but a house made from trees is not. Or nature might refer to our own environment on the earth’s surface, primarily considering the ecological biosphere but including also the air, soil, rock, and water that sustains life. Or again, there is a long-running debate about whether humans are to be included as a part of nature, as opposed to nature being everything else that is not humanity. In this work, however, nature is intended to be a very inclusive term. All parts of the natural world (living, non-living, human, and created-by-humans) are included, and “world” is interpreted as the entire universe in this context. Put differently, we may equate nature with cosmos (using an older word) or with material reality. The fact that “cosmos” and “material reality” have rather differing philosophical connotations is intentional here; nature might partake of either connotation, and this is precisely the issue we intend to explore.
Concepts of nature have varied radically in different cultures and at different times. To get a sense of the range and richness of such differing apprehensions before we engage in our main project, in this chapter we will look at three of the many possible interesting cases. Forming an appreciation of this variability will be helpful in evaluating the validity of unfamiliar conceptualizations as we proceed later.
Greek Ideas of Nature in Antiquity
The interest of the ancient Greeks in nature, and the way in which they approached nature, varied greatly over the centuries. Not only did their ideas evolve with time, but they also often proposed contesting ideas between the various schools at the same time, with varying degrees of scientific, philosophical, and religious content. The nature concepts of Greek civilization are interesting on their own merits, but they are also highly important due to their influence on later civilizations such as those of the Romans, Islam, and Europe. Not surprisingly, many of the basic underlying presuppositions of modern science have their roots in the thinking of these Hellenic nature philosophers.
Some of the earliest thinking about nature came from the Ionian philosophers. Prior to their work, Greek approaches to nature seem to be mythic and poetic rather than philosophical. In Homer, for example, the forces of nature are personified by the wills of anthropomorphic gods. The Ionians adopted a more rational approach, asking what we could know of the order underlying appearance in the world. For them, the fundamental question to ask turned out to be: what is the universal substance of which all things are made. Thales, the earliest of them, believed that all things originate in water. We may presume that for Thales and his audience water was not the prosaic chemical compound that we think of but rather the life-giving and protean archetypal fluid. But this fluid-ness presents a problem, because we have no clear way to understand how rocks or fire arise from a substratum of water. The ideas of Anaximander address this problem. He proposes that all things are made from a kind of universal principle, an even more protean and unformed substance having no specific properties of its own, which he refers to as the “Boundless” and considers imperishable. Anaximander devised a pictorial model of swirling eddies in the Boundless, separating out propertied substances from which the world is made. An issue with these ideas is the lack of any clear explanation of how these substances that do have properties might arise from the formlessness for the Boundless. Perhaps to address this issue, the third major Ionian thinker, Anaximenes, proposed that all things are made from air. He supplemented this proposition with the idea that air undergoes condensation and rarefaction so as to produce the variety of properties that we see in material substances in the world. This advanced Ionian philosophy by providing a kind of mechanical explanation for how the universal substance could give rise to variety.
These mechanical looking models should not mislead us into thinking that the Ionian philosophers proposed a mechanistic world. The universal substance of Anaximander “envelopes everything, produces everything, governs everything. It is the supreme divinity, possessing a perpetual vitality of its own.”16 Part of the inherent property in the primal substance featured in all of the Ionian systems is some sort of inner directedness toward the ultimate forms it takes. Despite the mechanical rarefactions and condensations of Anaximenes’ air, he continues “in thinking of the primitive substance as divine […] an immanent God identical with the world-creative process itself.”17 And yet, many Ionian explanations of particular phenomena such as lightning and earthquakes are presented as mechanical and pictorial models, as well as important features of their overall cosmological schemas. We see then a key tension in the Ionian conception of nature: the explanations seem to involve what we might think of as causes, but the behaviors are always eventually traced back to inherent properties of the universal substance, which are equated to the divine and have no further explanation. The decisive innovation introduced by Ionian philosophy was the assumption that nature does present an underlying order and regularity that can be explored by the use of reason, and this program was taken as far as it could go based on the limitations of the essential question that the Ionians were asking.
A rather different approach was taken by the Pythagorean school. In addition to their religious and political dimensions, the Pythagoreans developed a nature philosophy based on number. Numbers, and mathematical relationships more generally, are the fundamental basis for the workings of the world. Their thinking is difficult to understand from a modern perspective, because genuine mathematics, number mysticism, speculative reasoning, and observation are all combined indiscriminately into a system composed of parts that seem incompatible yet were synthesized together. One of the key elements of this synthesis was the famous relationship discovered between mathematics and music. All of the consonant musical intervals on the scale are formed by plucking strings whose lengths are integer ratios (2/1 for the octave, 3/2 for the fifth, and so on). This profound connection between number and harmony was central to the Pythagorean work, and it was indeed based on observation of the real world. The investigations of the Pythagoreans into music continued to find broader and deeper relationships to number, and they also performed important work in astronomy (as well as mathematics itself).
There are at least two reasons why Pythagoras and his followers are important. One reason, of course, is the immense influence that the idea of mathematics governing nature has historically enjoyed; we will be returning to this theme often, but the work of Kepler alone is enough to make the point (not to mention virtually all of contemporary physics). The second reason is more directly related to our present story. The Ionian philosophers had identified the key question concerning nature as being about the substance of which it is made, but the emphasis of the Pythagoreans on number shifted the key question away from substance and onto form. The numbers have no substance, yet they are the central concept because they govern the behavior of things. The substanceless numbers are in some sense more real than the substance itself, which merely provides a medium through which the number relationships can manifest themselves. This idea of the superiority of form was to become quite important in Greek thought, and at this very early juncture it provides an alternative formulation to the concept of nature set forth by the Ionians.
Reflection on the issues raised by postulating an underlying universal substance, when the world we observe shows a huge degree of variety, greatly influenced Greek thinking on nature. The question of Becoming, how the things of the world arise from an eternal unchanging Being, was answered in many different ways. Opposing views were proposed by two early giants of Greek philosophy, Heraclitus and Parmenides. For Heraclitus, change was the central feature of reality. All things are process and transformation, not static Being. There is an eternal principle, which he identifies as fire, but this principle itself is the principle of creation, destruction, and transformation. The true underlying order he calls Logos, but it’s not clear whether this is within the comprehension of humans. Parmenides, in contrast, maintains that all change is merely illusion and that static Being is the only true reality. The implications of this position are far-reaching: if all that we see is change, and change is an illusion, then everything that we infer from the evidence of the senses is unreliable opinion. The only truth that we can know comes from reason, not the senses. Hence, Parmenides does give us a physical theory of the Ionian kind, but he labels it as merely opinion. These two radical contrasting views