Plutarch, in this essay on the E at Delphi, tells us that beside the well-known inscriptions at Delphi there was also a representation of the letter E, the fifth letter of the Greek alphabet. The Greek name for this letter was EI, and this diphthong, in addition to being used in Plutarch’s time as the name of E (which denotes the number five), is the Greek word for if, and also the word for the second person singular of the verb to be (thou art).

In searching for an explanation of the unexplainable it is only natural that the three meanings of EI ( five, if, thou art) should be examined to see if any hypothesis based on any one of them might possibly yield a rational explanation; and these hypotheses constitute the skeleton about which is built the body of Plutarch’s essay. From it we gain some interesting delineations of character and an engaging portrayal of the way in which a philosopher acts, or reacts, when forced unwillingly to face the unknowable.

Plutarch puts forward seven possible explanations of the letter:

(1) It was dedicated by the Wise Men, as a protest against interlopers, to show that their number was actually five and not seven (EI = E, five).

(2) EI is the second vowel, the Sun is the second planet, and Apollo is identified with the sun (EI = E, the vowel).

(3) EI means if: people ask the oracle IF they shall succeed, or IF they shall do this or that (EI= if).

(4) EI is used in wishes or prayers to the god, often in the combination εἴθε or εἰ γάρ (EI = if or if only).

(5) EI, if, is an indispensable word in logic for the construction of a syllogism (EI = if).

(6) Five is a most important number in mathematics, physiology, philosophy, and music (EI = E, five).

(7) EI means thou art and is the address of the consultant to Apollo, to indicate that the god has eternal being (EI = thou art). ¹

Attempts to explain the letter have been also made in modern times by Göttling, Berickte der Sacks. Gesell. der Wiss. I. (1846-47) pp. 311 if., and by Schultz in Philologus (1866), pp. 214 if. Roscher, in Philologus (1900), pp. 21 if.; (1901), pp. 81 if.; (1902), pp. 513 if.; Hermes (1901), pp. 470 ff. (comment also by C. Robert in the same volume, p. 490), and the Philologische Wochenschrift (1922), col. 1211, maintains that EI is an imperative from εἶμι, go, addressed to the person who carne to consult the oracle, and that it means go on, continue into the temple. The value of this explanation is somewhat doubtful, since EI in this word ( εἶμι) is a true diphthong, and so is not generally spelled with simple E except in the Corinthian alphabet. Although Roscher cites a few examples from inscriptions in other dialects where the true diphthongal EI seems to be represented by simple E, his evidence is not convincing.

O. Lagercrantz, in Hermes, xxxvi. (1901) pp. 411 if., interprets the E as meaning ἦ he said. To this, of course, Roscher objects and suggests that Lagercrantz might have thought also of ἦ verily. Thus all the various possibilities of interpretation have in turn been suggested, and rejected by others.

W. N. Bates, in the American Journal of Archaeology, xxix. (1925) pp. 239-246, tries to show that the E had its origin in a Minoan character E associated with Ge (as is shown by the evidence of a Cretan gem in the Metropolitan Museum of New York) and later transferred to Delphi. Since the character was not understood, it, like other things at Delphi, came to be associated with Apollo. This character has been found on the old omphalos discovered in 1913 at Delphi in the temple of Apollo. ²

Interesting are the two coins reproduced in Imhoof-Blumer and P. Gardner, A Numismatic Commentary on Pausanias, plate x. nos. xxii. and xxiii. (text, p. 119), which show the E suspended between the middle columns of the temple. Learned scholars should note that the letter represented is E, not EI: therefore such explanations as are based on the true diphthong are presumably wrong.

The title of the essay is included in the catalogue of Lamprias, where it appears as No. 117. It is not infrequently quoted or referred to by later writers. It has been separately edited by Bernardakis in the volume of essays in honour of Ernst Curtius, Leipzig, 1894. Of interest is also The Delphic Maxims in Literature, by Eliza Gregory Wilkins, Chicago, 1929.