We at the height are ready to decline.
There is a tide in the affairs of men
Which, taken at the flood, leads on to fortune;
Omitted, all the voyage of their life
Is bound in shallows and in miseries.
On such a full sea are we now afloat,
And we must take the current when it serves,
Or lose our ventures. (IV.ii.269–276)

Brutus speaks these words in Act IV, scene ii in order to convince Cassius that it is time to begin the battle against Octavius and Antony. He speaks figuratively of a “tide” in the lives of human beings: if one takes advantage of the high tide, one may float out to sea and travel far; if one misses this chance, the “voyage” that one’s life comprises will remain forever confined to the shallows, and one will never experience anything more glorious than the mundane events in this narrow little bay. Brutus reproaches Cassius that if they do not “take the current” now, when the time is right, they will lose their “ventures,” or opportunities.

The passage elegantly formulates a complex conception of the interplay between fate and free will in human life. Throughout the play, the reader must frequently contemplate the forces of fate versus free will and ponder whether characters might be able to prevent tragedy if they could only understand and heed the many omens that they encounter. This musing brings up further questions, such as whether one can achieve success through virtue, ambition, courage, and commitment or whether one is simply fated to succeed or fail, with no ability to affect this destiny. Here, Brutus conceives of life as influenced by both fate and free will: human beings must be shrewd enough to recognize when fate offers them an opportunity and bold enough to take advantage of it. Thus, Brutus believes, does man achieve a delicate and valuable balance between fate and free will.

This philosophy seems wise; it contains a certain beauty as well, suggesting that while we do not have total control over our lives, we do have a responsibility to take what few measures we can to live nobly and honorably. The only problem, as the play illustrates over and over again, is that it is not always so easy to recognize these nudges of fate, be they opportunities or warnings. The characters’ repeated failures to interpret signs correctly and to adapt themselves to events as they unfold form the basis for most of the tragedy that occurs in the play.