Norman DeWitt explains in Norman DeWitt's Epicurus And His Philosophy - Chapter 1 (A Synoptic View of Epicureanism) that due to translation issues there is much confusion today between the concepts of the “greatest good” and the “goal” of human life. He explains the proper distinction in his chapter entitled “The New Hedonism” which contains the following:
“The belief that life itself is the greatest good conditions the whole ethical doctrine of Epicurus. He sees life as narrowly confined between the limits of birth and death. Soul and body are born together and perish together. Metrodorus gave telling expression in figurative language to this melancholy belief, Vatican Saying 30: “The potion mixed at birth for all of us is a draught of death.”
There was for Epicureans no pre-existence, as Plato believed, and no afterlife, as the majority of mankind believed. Epicurus himself expressed the thought with stark directness, Vatican Saying 14: “We are born once and we cannot be born twice but to all eternity must be no more.” Thus the supreme values must be sought between the limits of birth and death. The specific teaching that life itself is the greatest good is to be drawn from Vatican Saying 42: “The same span of time includes both beginning and termination of the greatest good.” If this seems to be a dark saying, the obscurity is dispelled by viewing it as merely a denial of belief in either pre-existence or the afterlife.
As Horace wrote, concluding Epistle i.16 with stinging abruptness, “Death is the tape-line that ends the race of life.” Editors, however, misled by the summum bonum fallacy, equate “the greatest good” with pleasure and so are forced to emend. The change of a single letter does the trick but fundamental teaching is obliterated. While this quoted statement is first-hand evidence of the Epicurean attitude, the syllogistic approach is also known from an extant text, of which the significance has been overlooked. The major premise is the assumption that the greatest good must be associated with the most powerful emotions, that is, the worst of all fears and the greatest of all joys.
Now the worst of all fears is that of a violent death and the greatest of all joys is escape from the same. The supporting text runs as follows: “That which occasions unsurpassable joy is the bare escape from some dreadful calamity; and this is the nature of 'good,' if one apprehend it rightly and then stand by his finding, and not go on walking round and round and harping uselessly on the meaning of 'good'.” This passage marks the summary cutting of a Gordian knot, the meaning of “good,” upon which Plato had harped so tediously. Epicurus finds a quick solution by appealing to the Feelings, that is to Nature, as the criterion; it is their verdict that the supreme good is life itself, because the strongest emotions are occasioned by the threat of losing it or the prospect of saving it.