Heraclitus and the

Heraclitus of Ephesus (540-480 BC) seems to have been the first philosopher to reflect critically on all of the different kinds of things there are—nature and art, human norms and values, language and reality, knowledge and opinion, life and death—and tried to understand how they “all hang together.” His writings still retain some of their intellectual electricity, not least because he was the first philosopher to recognize and reflect on the problem of subjectivity in relation to knowledge and truth.

Heraclitus chose to convey his “Truth” though haiku-like sayings, most of which, like the Pythagorean akousmata, have a double meaning. But his own thought was often obscure. Some Heraclitean writings pick up on the idea of a Logos, that there is an ultimate, enduring ground of nature. Others, such as the doctrine of fire, invite the thought that there is no underlying substance to reality, no rational order to the world, nor objective knowledge of nature or man. Perhaps most puzzling are those statements by Heraclitus which seem to assert a doctrine of flux, and the co-presence of opposites: “Of those who step in the same rivers, different—again different—rivers flow. It is not possible to step twice into the same river. We step and we do not step into the same rivers. We are and we are not.”

Consider the following philosophical puzzle, prompted by Heraclitus’ theory of flux, which asks how, given the flux of sensible things, objects retain their identity over time. (An extreme Heraclitean view was that things have no objective identity over time, but are merely temporary collections or bundles of properties. But how could even properties have identity over time?)

The Ship of Theseus

(from Marc Cohen)

This puzzle tells of a voyage by Theseus’ ship to Crete, which was followed by a scavenger ship that periodically picked up planks falling from Theseus' ship, Theseus replacing these with other planks they found in the water. When Theseus sailed back to Athens from Crete—still followed by the other—every part of his ship had been replaced (including sails, rudder, etc.) and the scavenger ship was now constructed of what had previously made up Theseus' ship.

The puzzle: was Theseus still in the same ship or a different one? If different, when had it changed? If it did change, did it change into the scavenger ship, so that now the scavenger ship was identical with Theseus' old ship, or were these different, too?

Let Theseus' original ship = A, the ship he returns to Athens with = B, and the scavenger ship on its return to Athens = C. Is A = B? or is A = C? The Presocratics were familiar with two theories of identity.

On the component parts theory (CPT), the identity of an object depends on the identity of its component parts. Since this view asserts that sameness of parts is a necessary condition of identity, A cannot = B, and Theseus must have been on (at least!) two different ships. Moreover, since their parts are the same, A = C, i.e. Theseus' original ship is now the scavenger ship. Obviously this is problematic. If things cease to be themselves with any change of its parts, their ‘existence’ is very fleeting, since physical things are constantly losing some of their material components.

On the spatio-temporal continuity theory (STC), a persisting object must trace a continuous path through space-time. This is compatible with a change of parts, so long as the change is gradual. But how much can it change? what determines which part of the thing must be preserved, and which can be lost, for it still to be the same entity? For example, let us suppose that ship A is gradually reconstructed but that as that occurs, it changes slightly—it gets wider, there are slightly fewer oars, the steering mechanism is looser, the sails are smaller, it moves more slowly through the water. At some point we might say, “It just isn’t the same ship anymore.” But when would that be?

Consider too that an object can be disassembled, then reassembled, e.g. a bicycle's parts are placed in separate boxes and shipped across country, the boxes then unpacked and the bike reassembled. How do we account for its identity? There is no continuously existing bicycle-shaped object tracing a path through space-time. CPT, however, says it is the same bicycle, since it is made of the same parts as the first one.

· How would you answer Heraclitus' puzzle concerning the identity of objects?

· Which theory do you think is correct and why?

· How might we re-conceive this puzzle in relation to the identity of the self or the person as they age and change? What makes someone the same person?

· How might we think about identity in relation to evolution, e.g. the identity of species, or of individuals as the carriers of genes?

As we have seen, both the Milesians and the Pythagoreans developed a scientific vision of reality. Heraclitus then introduced a new consideration, when he reflected on the possibility that human knowledge is relative to ever-changing concepts, perspectives, and changes in nature itself. The epitome of the Heraclitean vision seems expressed in the radical doctrine of fire and the related notion of the co-presence of opposites, the paradoxical idea that something can both have and not have the same property in different ways, both be and not be at the same time. There is something logically troubling in this idea, which grabbed the attention of Parmenides.

Parmenides of Elea (c. 530-450 BC) reacted sharply against this Heraclitean teaching: “They are carried along by experience, deaf as they are blind, amazed, uncritical herds, for whom to be and not to be are judged the same and not the same, and for whom there are in all things opposites.” (Curd, Parmenides #6.) Against the Heraclitean idea of the co-presence of opposites, Parmenides insists there is a rational basis of all truth and all being: “That it is and cannot not be is the path of truth.” And “In no way may this prevail, that things that are not, are.” (Curd #2, 7).

Parmenides’ insight—later called the principle of non-contradiction (PNC)—is the most basic safeguard against falsehood, incoherence and delusion in reasoning. It is the basis of rational thought, and enables us to conceive of the world as it is. For if we try to imagine what it would mean, if some X could both be and not be or if X could both have and not have the same property Y (at the same time and in the same respect), then all rational inference breaks down. (For example, if life both is and is not a dream, then life both is and is not real. Then what is real is also not real, and vice-versa. Then there is no difference between real and not real, sameness and difference, being and nothingness, i.e. there is radical incoherence in thought and being.)

And yet we cannot prove the PNC is true, without using it to prove it—the logical fallacy of “begging the question.” The PNC is an ultimate principle of reasoning, like A = A (the principle of identity), which would not itself have any meaning, if A could also be not-A.

It follows that logic involves modality: whereas some things merely are or are not the case (p), other things must or cannot be the case, e.g. the logical implication of two true statements must be a true statement ([p & (pàq)] à q), whereas two contradictory statements cannot both be true ~ (p & ~p). The idea that some things must be or cannot be—the ideas of necessity and impossibility—constitute, in addition to identity, being and non-being, features of the logical structure of thought, and of all proofs, such as are found in the mathematical sciences. The laws of mathematics are necessarily true.

In addition to being the grandfather of Greek logic, Parmenides also played an enormously influential role in all later Greek metaphysics. Whereas Heraclitus’ ultimate insight was to see “fire” i.e. change at the core of being, Parmenides insists “That it is and cannot not be is the path of truth” and goes on to indicate the basic metaphysical attributes of “what-is”: it is (i) un-generated, (ii) imperishable, (iii) whole, (iv) self-same, (v) unchanging, and (vi) complete or full, as well as (vii) known by reason, not the senses (fragment #8).

These attributes imply Parmenides is thinking of “what-is” as “always-being” or “eternal-being” and therefore as something that must be rather than as something that merely happens to be and could not be, an interpretation would help explain the otherwise puzzling logic in quote #6: “That which is … must be. For it is possible for it to be; and it is not possible for nothing to be.” This argument is clearly false in relation to contingent beings which can cease to exist, e.g. cats or smiles. For these things “are” for a certain period of time, and later “are not.” But if what is is something that must be, it cannot cease to be.

The traditional interpretation of Parmenides presents him as a metaphysical monist: there is one, eternal, unchanging reality, which alone “is”—whereas the world of contingent, changing things, the world of appearances, “is not.” (Later Eleatics would identify “being” with Universe, Logos, Number, God, Soul, Atoms, even Truth.) On this view, Parmenides’ conception of reality is as follows:

A more recent interpretation claims that Parmenides is not a monist who regards the world of appearances as illusory, but that he is offering a modal theory of being, and his conception of reality is:

On this view, Parmenides thinks that reality has both a necessary, universal structure, which determines both what must be (i.e. what is necessary) together with what cannot be (i.e. is impossible), as well as the contingent, particular things and events that happen within it.

Here we have again appearance vs. reality, but with an essential core or structure of an ever changing totality of phenomena, which are also real, if not enduring. “Necessary being” in this sense picks out those aspects of the world that are universal and unchanging, the Logos or essential form of reality. Obviously, a modal conception of reality would have been a powerful conceptual tool to help the ancient thinkers untangle what was meant and not meant by “what is.” This distinction is critical to natural science, for example, insofar it is concerned with causal laws and powers in nature—laws which describe things that must be in conformity with and cannot be opposed to the laws, e.g. when fire is mingled with paper in dry air, the paper must burn, given the nature of those elemental bodies or their underlying atomic structures.

But it also seems possible that in claiming that “what is” is something that must be, Parmenides is thinking of what is not as the essence or inner structure of being, but as itself an entity or being—a necessary being, in contrast to thing that come to be and perish. Is this concept even coherent? Can we not imagine that anything that can be said to exist, whether it is the starry heavens or God or soul or number or whatever, can also not exist? And what are the implications of this concept? (For example, if we say that God is a necessary being, does that imply that God exists? It seems it must, since if God is defined as existing necessarily and we conceive of God as not existing, we are not conceiving of God! This and other puzzling consequences seem to follow from Parmenides’ concept of necessary existence.)

There is yet another consideration, when interpreting Parmenides’ notion of Being. For not only does “what-is” not change, according to Parmenides, it is not incomplete or anything less than fully present: “Remaining self-same in itself, being is what it is, and does not change; for it is contained by Necessity within the bonds of Limit; nor is it fitting for what is to be incomplete, for being cannot be lacking—or it would not be.” (#8.) Thus understood, “what is” is associated not only with necessity and ever-enduringness (as might be found in laws of logic or of nature), but with fullness and goodness, i.e. with perfection. Plato would identify the ultimate source of all reality as the Good, the principle which solicited all beings toward unity, self-perfection and knowledge; medieval philosophers would identify Parmenidean Being with God, conceived of as Alpha/Creator and Omega/End of all things. Parmenides’ discussion of Being and its attributes shaped all later Greek metaphysics and philosophical theology, which had to ask: Is there an Eternal Perfect Being, or are all beings material and contingent?

Parmenides’ student, Zeno, was also drawn to the idea of logic as the basis for objective knowledge concerning the world, and to the idea that the senses offered subjective, contradictory and misleading evidence. Zeno pioneered the method of negative dialectic, which sought to prove logically, starting from his opponents’ own hypotheses, that they led to contradictory conclusions, and therefore had to be mistaken. (Socrates would make constant use of this method in his own “Socratic dialectic.”)

Zeno’s paradoxes, all aimed at displaying the incoherence of the sensible world, include:

1. The heap. If a given number of grains of sand n make a heap, it will not cease to be a heap, if one is taken away, n-1. But from this one can conclude that if any given number of grains make a heap, so do all lower numbers, down to zero. Conversely, if n grains are not a heap, neither are n+1, up to infinitely. Thus every collection of grains is and is not a heap. (Curd Zeno #3, 13.)

2. Paradoxes of motion, e.g. the arrow, Achilles. If the arrow flies toward the target, it must pass through ½ the distance, then ½ of the remaining distance, and so on. It will always never reach the target. Likewise, Achilles will never catch up with the tortoise. (#6-11)

3. Paradoxes of infinity. Zeno argued that if the world or any part of it were composed of infinitely many atoms, it would be unlimited in size, which he thought impossible. (Suppose it is infinitely large; how could it be made bigger? But it seems anything can be made bigger by addition.) Likewise, if the world or any part of it were composed of infinitely small atoms, it would not be of any size, i.e. it would not exist.

Or consider time. Here is a Zeno-type argument used centuries later to prove the universe had to be finitely, not infinitely old (i.e. had to have come into being): Suppose a point in the infinite past, t-I, with time going infinitely backwards as it were. How would you ever traverse from t-I to t-0, now? Go as far back as you wish, you will never get to t-I. So the universe must be finitely old, i.e. must have come into being. (Aristotle would resolve some of these puzzles by distinguishing the potential from the actual infinite, and denying the reality of the latter.)

Western philosophy is sometimes described as an ongoing debate between the scientific-materialist tradition of the Milesians and the religious-idealist tradition of the Pythagoreans. It could also be described as a fight between Heracliteans (partisans of change, relativity and contingency) and Eleatics (partisans of permanence, universality and necessity).

The story of the Eleatic tradition would be incomplete without mentioning Xenophanes (580-530 BC), Parmenides’ teacher. Whereas Parmenides and Zeno were known for investigating the concept of “being,” Xenophanes is known as the first theologian in history (“theology” = theos, “god” + logos, “rational study of”).

· If oxen and horses and lions had hands, they would draw gods in the shape of oxen, horses, and lions. The Celts give the gods red hair, the Nubians make them black. (Curd Xenophanes #6)

· God is one, greatest among gods and men, not at all like mortals in thought or body. Without effort he shakes all things by the thought of his mind. (#8-10)

· No man has seen nor will anyone know the truth about the gods and the things I speak of, for even if what the man said was true, he would not know, but only shapes a belief about it. (#13)

1. Anthropomorphism, the idea that humans typically imagine their gods to be in human form, a projection of themselves. This idea corresponds to the commandment against idolatry, that Israel “make no graven images.” But how far are we to take this thought? What can be said about God that does not relate somehow to human persons?

2. The philosophical concept of God, as one, non-corporeal, radically other: God is “not at all like mortals in body or thought” (Curd, #8), and “shakes all things by the thought of his mind” (#10). Clearly this concept of God is closer to the monotheistic and transcendent Biblical conception, the “I am,” than the polytheistic anthropomorphic Greek gods. But Xenophanes’ God is not personal. Does his idea therefore lack an essential element of what is meant by God?

3. Agnosticism, i.e. the skeptical insight that the philosophical idea of God, even if true, is a matter of faith, not knowledge. Here too Xenophanes seems to have recognized an important theological insight—that later religious traditions would forget, again and again.