The Cratylus is not one of Plato’s most read dialogues. It’s kind of a shame, because it addresses two fundamental questions:
What is the relationship between language and reality?
Is reality constant and unchanging or is it in constant flux (the position attributed to Heraclitus, and represented in the dialogue by Cratylus)?
The original date of the dialogue is in some dispute, and also the order in which it fits in Plato’s “middle dialogues”. The maturity of Plato’s thoughts seem to definitely place it well before The Republic, also one of the middle dialogues.
The dialogue opens with opposing positions taken by Socrates’ two companions here, Cratylus and Hermogenes. Hermogenes states Cratylus’ position, “Cratylus says, Socrates, that there is a correctness of name for each thing, one that belongs to it by nature.” Hermogenes’ own position is a contrary one, “I believe that any name you give a thing is its correct name.” “No name,” he says, “belongs to a particular thing by nature, but only because of the rules and usage of those who establish the usage and call it by that name.”
That gives us the crux of the argument to come. Call it conventionalism vs. essentialism.
Socrates’ first move in the dialogue is to establish that things do have natures. It’s a quick argument, a rebuttal to Protagoras’ relativism, which Hermogenes defends. The argument turns on whether there can be facts of the matter, e.g., that there are wise men and foolish men, as opposed to everything being left to the judgement of each individual. You could object that the argument is too quick, that that formulation of Protagoras’ relativism is extreme and that other positions are possible.
There will be other arguments in favor of essentialism as the dialogue goes on. I don’t think that everything depends on this rejection of Protagoras’ relativism.
Socrates goes on to argue that speaking, like other things, has a nature, and that it is possible to distinguish speaking correctly, i.e., according to its nature, from speaking incorrectly. Speaking correctly is speaking truly.
I’ll skip a bit ahead, since I imagine you can see the direction of the argument. Speaking correctly will imply speaking truly of the natures of things, in particular naming them in accordance with their natures. Socrates says, “We cannot name things as we choose; rather, we must name them in the natural way for them to be named and with the natural tool for naming them.”
The “tools” Socrates invokes here are rules for naming things. “Name-givers” as Socrates will call those who name things, are in a sense legislators, “rule-setters” for how things will be spoken of.
Socrates draws an analogy between name-givers and craftsmen in general, saying that name-givers are a rare sort of craftsman, but like other craftsmen, they are skilled at their trade. In particular they “know how to embody in sounds and syllables the name naturally suited to each thing.”
Also, just as a blacksmith may fashion drills that differ in their details, so long as the drills they make are made correctly, i.e., in accord with the nature of drills, so might different name-givers, working in different languages, fashion different names for the same things, so long as they accord with the natures of the things they name. This accounts for differences in names from language to language.
The next question Socrates takes up is what it means for a name to accord with the nature of the thing it names. He does this through a long series of etymological arguments, tracing back from the names of gods, human virtues and vices, truth, and knowledge (the translator, C.D.C. Reeve gives a nice summary of the categories of names Socrates covers in his introduction to the book).
But before going on to that, note that what Plato (via Socrates) treats as a “name” is a broader category than what we would call a name. “Names’ include proper nouns, like names of people or places or gods, but also common nouns, names for objects, actions, and attributes. It may also include adjectives, like “good.”
A couple of examples helps. The word for gods, “theos”, derives from “thein”, meaning to run, because the gods (originally likely the planets, sky, and earth) were in constant motion. “Daimons”, the name for the first humans, derives from “daimon”, denoting wisdom.
Often Socrates notes that the original names for such things have changed over time, having been “covered over” with embellishments or “to make them sound good in the mouth.” Those changes amount to corruptions of the original names, and a loss of the wisdom contained in those original names. Etymologies like the ones he demonstrates here can uncover those original names.
The names themselves are not just neutral tags for the things they name, they contain descriptive content, e.g., that the gods are constantly in motion. As another example, Socrates says of the name for the good, “[The good] always does away with (luei) any attempt to let motion end, making it unceasing and immortal. In my view, it is for this reason that the good is said to be ‘lusiteloun’, because it does away with (luon) an end (telos) to motion.”
When we unpack the “meanings” of names etymologically we understand better what the things, e.g., the good, are. So the etymologies aren’t just historical reconstructions, they are uncoverings of wisdom contained in the “original names” of things.
This is at least somewhat borne out by what Socrates says about the name for names themselves. He says, “Well , onoma (‘name’) seems to be a compressed statement which says: ‘this is a being for which there is a search.’” He then goes on to connect this notion of a search to the etymologies of truth (Aletheia), falsehood (Pseudos), and being (on or ousia).
But there is a tension here. If these names are well chosen by the name-givers, they will contain wisdom about the nature of the things they are names for. If they are well-chosen. And although Socrates speaks reverently of the name-givers, he doesn’t grant them infallibility.
That tension will come to a head toward the end of the dialogue. So far, the etymologies have traced names to other names, the name for gods to the name for running, etc. But etymology has to come to an end someplace, with some names that are elemental or primary.
Plato finds the relationship between these primary names and what they name in “imitation.” “It seems to follow that a name is a vocal imitation of what it imitates, and that someone who imitates something with his voice names what he imitates.”
But it’s not just any kind of imitating — it is imitation of the “essence” of the thing (e.g., not an imitation of the sound it makes or its shape). Naming seems to consist in imitating the being or essence of things via letters and syllables.
Now the job becomes one of describing in turn what the imitation consists in, how letters and syllables can imitate the essences of things (and whether or not they do so well or correctly). Since these primary names are the basis for all other derivative ones, the correctness of those primary names is the basis for the correctness (and embedded wisdom) of all names.
As an example, Socrates presents the letter “r” as a name-giver’s tool for copying (or imitating) motion, as in “rhoe" (“flow”) and in other examples of words naming motion.
It seems to be both the sound of the letter and the way it is produced by the tongue that are the basis for the imitating. “He [the name-giver] saw, I suppose, that the tongue was most agitated and least at rest in pronouncing this letter, and that’s probably why he used it in these names.” He repeats the same point about the motion of the tongue to describe how other letters (“i”, “d”, . . . ) are apt tools to imitate other qualities, like smallness or smoothness or a blowing outwards of something.
This brings us back to the tension I mentioned above. If the correctness of these primary names provides the basis for the correctness of all other (driver or compound) names, and if that correctness consists in their properly imitating the nature of the things they name, are those primary names in fact correct?
Socrates rightly points out that the name-givers must have had knowledge of the things they named independently of their names. They had to know the things in order to create names for them in the first place. So they knew them directly, foreshadowing the direct knowledge of Forms he develops in The Republic.
Did the name-givers create correct primary names?
I think the dialogue actually ends with that question still open. Cratylus never gives up his defense of Heraclitus, finding evidence in the prevalence of primary names that connote (or really, “imitate”) motion or change. Socrates offers one final argument against Heraclitus. He argues, among other points, that knowledge in an Heraclitean world would be impossible, because as soon as we gained knowledge of something, it would have changed, and our knowledge would no longer be of the thing. What’s more the thing would no longer be itself. It gets downright Parmenidean at this point, although it does foreshadow again arguments that Plato will make about knowledge and Forms in later dialogues.
The dialogue closes with the promise of future conversations. Socrates gets no final “Certainly so, Socrates” from Cratylus.
To go back to the two fundamental questions:
What is the relationship between language and reality?
Plato’s answer here is really a theory of “names”, where that category is a broad one. But he doesn’t explicitly provide what we would call, in contemporary philosophy, a theory of meaning or even a theory of reference per se. His theory is more one of the history and origin of names. And there his interesting claim is that names “imitate” the things they name, more specifically they imitate the “nature” of those things. Plato doesn’t fully explain what he means by their “nature” here — that’s going to wait for a more fully developed treatment of his theory of Forms, e.g., in The Republic.
The imitation that binds names to things, if they are correctly named, is a likeness between that nature of a thing and the qualities of letters and syllables, the sounds of letters but also even the feel of the letters and syllables in the mouth and on the tongue.
Given this “likeness” between names and the things they name, we can come to know things by knowing their names. However, to do so is to both count on the things being correctly named (i.e., truly imitating the nature of things) and to know things indirectly, rather than directly knowing the natures of things (again something to be developed in Plato’s theory of knowledge and the Forms).
Is reality constant and unchanging or is it in constant flux (the position attributed to Heraclitus, and represented in the dialogue by Cratylus)?
Here I don’t think we get a full answer. As I said, Cratylus leaves the conversation still holding to a Heraclitean position. Socrates has presented several arguments, but he hasn’t proven his case against Cratylus and Heraclitus. The “primary names” give mixed results, some conveying a Heraclitean emphasis on motion and change and others a stop to change (associated with a "d" rather than "r" sound and feel). Both, though, as I said above, are fallible, as the name-givers may have or may not have named the primary things correctly.
Aristotle reports in his Metaphysics that Plato learned about Heraclitus’ thoughts from the real-life Cratylus. So the relationship portrayed in the dialogue has some validity, as may the open question at the end of the dialogue.
Plato’s later development of his theory of Forms and his theory of knowledge (especially in the Theatetus and The Republic) combines Heraclitean insights with his own essentialism, so the open-endedness of the discussion here isn’t all that surprising. It’s like a rehearsal of arguments and positions to come.