A Man for All Seasons struggles with ideas of identity and conscience. More argues repeatedly that a person is defined by his conscience. His own position is depicted as almost indefensible; the Pope is described as a "bad" and corrupt individual, forced by the Emperor Charles V to act according to his will. But as More says to Norfolk, "What matters is not that it's true, but that I believe it; or no, not that I believe it, but that I believe it." More fears that if he breaks with his conscience, he will be damned to hell, while his associates and friends are more concerned with holding onto their own temporal power.
At another key point of the play, More testifies before an inquiry committee and Norfolk attempts to persuade him to sign the Succession to the Crown Act 1534 (pp. 78, Heinemann edition):
- Oh, confound all this. ... I'm not a scholar, as Master Cromwell never tires of pointing out, and frankly I don't know whether the marriage was lawful or not. But damn it, Thomas, look at those names. ... You know those men! Can't you do what I did, and come with us, for fellowship?
- And when we stand before God, and you are sent to Paradise for doing according to your conscience, and I am damned for not doing according to mine, will you come with me, for fellowship?
More's persecution is made to seem even more unjust by the inclusion of Eustace Chapuys, the long-time Imperial ambassador to England, into the story. Chapuys recognises More as a stout man of the church, and in Act II, after More's resignation from the Chancellorship, he informs More of a planned rebellion along the Scottish border, expecting More to be sympathetic. Instead, More informs Norfolk of the plot, showing him to be patriotic and loyal to the King. This, along with More's refusal to actually speak out against the King, shows him to be a loyal subject, and thus Cromwell appears to prosecute him out of personal spite and because he disagrees with the King's divorce.
Bolt also establishes an anti-authoritarian theme which recurs throughout his works. All people in positions of power – King Henry, Cromwell, Wolsey, Cranmer, Chapuys, even Norfolk – are depicted as being either corrupt, evil, or at best expedient and power-hungry. Bolt's later plays and film screenplays also delve into this theme. The theme of corruption is also illustrated, in Rich's rise to power, the Common Man being drawn into the events of the storyline, and in the (deliberately) anachronistic portrayal of Henry as a younger, athletic man (in 1530 he would have been in his forties and already putting on weight).
Although it is the law that eventually forces More's execution, the play also makes several powerful statements in support of the rule of law. At one point More's future son-in-law, Roper, urges him to arrest Richard Rich, whose perjury will eventually lead to More's execution. More answers that Rich has broken no law, "And go he should if he were the Devil himself until he broke the law!" Roper is appalled at the idea of granting the Devil the benefit of law, but More is adamant.
- "What would you do? Cut a great road through the law to get after the Devil? ... And when the last law was down, and the Devil turned round on you – where would you hide, Roper, the laws all being flat? This country is planted thick with laws from coast to coast, Man's laws, not God's, and if you cut them down – and you're just the man to do it – do you really think you could stand upright in the winds that would blow then? Yes, I give the Devil benefit of law, for my own safety's sake!"
The character of the Common Man serves as a narrator and framing device. A Brechtian character, he plays various small parts – More's servant, a publican, a boatman, More's jailer, jury foreman and executioner—who appear throughout the play, both taking part in and commenting on the action. Several sequences involving this character break the fourth wall—most notably, a sequence where the Common Man attempts to exit the stage and is addressed by Cromwell, who identifies him as a jury foreman. (Indeed, the "jury" consists of sticks or poles with the hats of the Common Man's various characters put on top.)
Bolt created the Common Man for two main reasons: to illustrate the place and influence of the average person in history, even though they are usually overlooked, and to try to prevent the audience from sympathising with the more titled characters such as More, realising that the audience is more closely related to him—a classic case of Brechtian alienation. The character's role in the story has been interpreted in many different ways by different critics, from being a positive to a negative character. Several of Bolt's subsequent works feature similar characters (e.g. The Thwarting of Baron Bolligrew, State of Revolution).