In Act 2, Scene 3 of "Julius Caesar," what is it that allows others to plot the assassination?According to Artemidorus
According to Artemidorus, it is Caesar's sense of his own indestructibility that allows him to be vulnerable to plots of assassination. He says,
If thou beest not immortal, look about you. Security gives way to conspiracy" (Act II, Scene iii, lines 6-7).
It is Caesar's misguided sense of security that allows others to effectively plot against him.
Caesar has been warned of impending danger before, in the previous scene by his wife Calpurnia. Calphurnia has had a dream in which she sees a statue of Caesar oozing blood, and, fearing for his safety, she begs him to stay at home. Caesar, although he initially consents, ultimately changes his mind, pridefully brushing off his wife's warnings, saying,
"Cowards die many times before their deaths, the valiant never taste of death but once...death, a necessary end, will come when it will come (Act II, Scene ii, lines 32-33, 36-37).
It is this presumptuous attitude against which Artemidorus is warning. He is reminding Caesar that he is not immortal, and to be careful. If he does not, conspiracy will find a way to penetrate his security when he least expects it.