Derrida’s strategy in Plato’s Pharmacy is to show that by giving speech more power than writing, Plato ends up using rhetorical tools and devices from writing to give power to speech, and thus to stand the primacy of writing on its head.
Derrida calls Plato’s writing style “pharmakon”, which Socrates mentions in the Phaedrus, in a passage where Socrates is discussing Egyptian gods’ views on writing. This passage was already complex given that it depends on the interpretations of Socrates’ Egyptian metaphors combined with the instruction in context of the rest of the dialogue. Derrida’s strategy with Nietzsche was to say that woman had three wholly different meanings to him. Pharmakon has three wholly different meanings to Plato as well: “curative medicine,” “poison,” and “undecidable.” Pharmakon, he tells us, is caught in a chain of significations. The two interlocutors “remain within the unity of the same signifier.” Their discourse plays with it. Derrida suggests that the translator citing only one of the possible meanings is itself an effect of Platonism: “Platonic text” is the idea that a text has one true, correct interpretation. This is “absolutely heterogenous,” says Derrida, and is constantly “composing” with the forces that will eventually destroy it.
Derrida shows that Socrates’s dependence on the notion of logos as “father” is very regressive. But then he adds that its regressivity is not the real problem. It depends on a transcendental signified, but more importantly, the metaphor of logos being indebted to a father carries with it an inherent relatedness to logos. The father cannot be assigned a “fixed spot” because he is too many things at once. “The god of writing,” he says, is a “floating signifier, a wild card, one who puts play into play.”
Plato at one point of deference chooses a logic that does not use the word pharmakon in differing senses of the word. Derrida says that this would lead to a dialetic of opposites. But later, Plato tries to define pharmakon through the King Theuth, and it turns out the definition is very black and white. Derrida implies that this is an appeal to authority. Plato is using the king to show a “play of appearances” which enable to pass as an essence or something like it. Derrida then judges Plato by standards used in other dialogues concerning good ambiguity and bad ambiguity. Where, in the Phaedrus, I’m not clear what kind of ambiguity Plato is employing. Derrida says that some of ambiguity is found in the oppositions being “external” to one another.
In the last part of the chapter, Derrida focuses on Plato’s theory of memory. For Plato, learning is to remember what is known in one’s soul. However, Derrida interprets a passage of Plato to be attacking the substitution of memory in a device (like text) for live memory. The memories are finite, which Plato knows, but Plato dreams of a memory with no sign. This is difficult to interpret. However, what I think Derrida is getting at is that Plato would like to have a mnemonic system that is both living in the person, i.e. live memory not declaratory text, but it doesn’t need a phonic signifier. Because writing has no effect on memory, it puts the reader to sleep, and its rigorously exterior, Plato wants both external memory and internal memory at the same time. This is why Plato writes in dialogue form, as if people are literally talking, but in fact it is writing. But he can’t have both.