The questioning of Howard, more so than that of any other witness, brings the specific conflict of the trial—creationism versus evolutionism—to an abstract level. Drummond argues to the court, “I am trying to establish, Your Honor, that Howard—or Colonel Brady—or Charles Darwin—or anyone in the courtroom—or you, sir—has the right to think!” When the judge responds that “the right to think is not on trial here,” Drummond barks back that the right to think “is very much on trial,” that it “is fearfully in danger in the proceedings of this court!” But regardless of the validity of Drummond’s argument, the nature of the American legal system limits it. Cates is on trial in a local court for breaking a law. Drummond, in his argument, does not challenge Cates’s guilt or innocence so much as the justice of the law itself, with respect to the Constitution of the United States. As we see at the end of the play, to make this challenge real, Drummond must bring it to a higher court.

The playwrights continually demonstrate their support for the evolutionists’ side by contrasting the defense’s compassion with the fundamentalists’ callous superiority. When Rachel takes the witness stand, Brady asks her to recount Cates’s reasons for his separation from the church community. Rachel recalls her father’s declaration that young Tommy Stebbins, who drowned to death, would be eternally damned because he was never baptized. Through the description of this event and of Cates’s departure from Hillsboro’s religious community, the playwrights illustrate Cates’s own moral development independent from organized religion. Cates declares to the court, “Religion’s supposed to comfort people, isn’t it? Not frighten them to death!” In this sympathetic portrayal, Cates emerges not as an atheist or an agnostic but as an individual who could not, in good conscience, abide by the cruel morality of the church.

Drummond’s argument emphasizes the distinction between “truth,” which he believes every man has a right to seek for himself, and absolute values of right and wrong as determined by religious authorities. Drummond implies that individuals and groups who use faith to stake their claims to righteousness often employ religion as a vehicle or justification for immoral pursuits. Reverend Brown, in his monomaniacal campaign to instill fear in the hearts of the people of Hillsboro, uses religion to buttress his authority. Although Brown enjoys respect from the townspeople, his condemnations of his own daughter and of Tommy Stebbins reveal his heartless interior. Cates, meanwhile, although he has broken the law and expressed doubts about religion, comes across as a compassionate figure. He stands up for Rachel and sincerely mourns Tommy Stebbins as a young life cut off too soon. Despite his status as a legal and religious outsider, Cates embodies a kindness and compassion that stand in sharp contrast to Reverend Brown’s unforgiving scorn.

Drummond suffers several procedural setbacks during the trial but makes his argument nonetheless. He uses Howard’s testimony to demonstrate that evolution represents human possibility rather than denial of God. Next, Drummond equates evolution with modern innovations, like the tractor, that have become essential elements in rural life. When the judge denies the scientific experts the opportunity to testify, Drummond uses Brady to show that a literal interpretation of the Bible leads into a web of contradictions. Although these tactics fail to exonerate Cates, they go a long way in discrediting his persecutors.

During the course of the questioning, the playwrights juxtapose the personalities and philosophies of Brady and Drummond. The stage directions differentiate the opponents: “The courtroom seems to resent Drummond’s gentle ridicule of the orator. To many, there is an effrontery in Drummond’s very voice—folksy and relaxed. It’s rather like a harmonica following a symphony concert.” Drummond’s delivery involves little ornamentation or finesse. Brady, on the other hand, uses a lengthy and grandiose style of oration that initially appeals to the court. But when the substance of Brady’s argument contradicts itself and his hubris becomes clear, Brady loses his popularity and support, while Drummond’s perseverance, grit, logic, and playful irony win over the courtroom.