Epperson v. Arkansas
The Supreme Court struck down Arkansas's 1928 law banning public school teachers from teaching that humans descended from other animals, ruling the law violated the First Amendment's ban on government establishing religion.
The Court found the law's only real purpose was to protect a particular religious view of human creation from a scientific theory that some considered incompatible with it, something government is never allowed to do.
“The overriding fact is that Arkansas' law selects from the body of knowledge a particular segment which it proscribes for the sole reason that it is deemed to conflict with a particular religious doctrine”
The majority's central reason for finding the law an unconstitutional religious establishment.
How it got here: An Arkansas chancery court struck down the law under the Fourteenth Amendment; the Arkansas Supreme Court reversed in a brief opinion; the teacher appealed to the Supreme Court as of right.
The Case in Depth
What happened
Arkansas had a 1928 law banning public school and university teachers from teaching that humans evolved from lower animals, or using textbooks that taught it. Susan Epperson, a Little Rock high school biology teacher, was assigned a new textbook containing an evolution chapter, putting her at risk of criminal prosecution and firing if she taught it as required. She sued to have the law declared unconstitutional, joined by a parent who wanted his children exposed to all scientific theories.
The question before the Court
Could Arkansas make it a crime for public school teachers to teach that humans evolved from other species?
Why it matters
The ruling ended state laws that banned teaching evolution because it conflicted with religious beliefs, protecting science curricula nationwide from being censored on religious grounds. It set a lasting rule that public schools cannot shape what is taught based on what any religious group considers true or false.
What changes now
This is a final merits decision. The Arkansas anti-evolution law is void and unenforceable, and Susan Epperson may teach the assigned biology curriculum, including evolution, without fear of prosecution or dismissal. The ruling effectively invalidated similar anti-evolution laws in other states, such as Mississippi's, though the Court did not directly rule on laws outside Arkansas.
What this does not decide
The Court did not decide whether the law was unconstitutionally vague, or whether it violated free-speech and academic-freedom rights — issues raised by the parties but left unaddressed because the establishment-of-religion violation was sufficient to decide the case. It also did not resolve whether states may remove subjects like evolution from curricula entirely for non-religious reasons.
Concurrences and dissents
Concurrence — Justice Black
“Under this statute as construed by the Arkansas Supreme Court, a teacher cannot know whether he is forbidden to mention Darwin's theory at all or only free to discuss it as long as he refrains from contending that it is true.”Black's argument that the law should have been struck down for vagueness instead.
Justice Black doubted the case was even a genuine live controversy given the law's decades of non-enforcement, and would have struck the law down only as unconstitutionally vague rather than reaching the establishment-of-religion question. He worried the Court's broad ruling might improperly extend federal oversight into state curriculum choices and questioned whether teachers have an unlimited right to teach whatever they wish.
Concurrence — Justice Harlan
Justice Harlan agreed the establishment-of-religion holding was correct but criticized the majority for also discussing the vagueness and free-speech arguments only to say those issues need not be decided, which he thought clouded an otherwise clear ruling and opened the door to unintended implications.
Concurrence in part — Justice Stewart
Justice Stewart agreed the law could not stand but would have struck it down as unconstitutionally vague rather than as a religious establishment violation, reasoning that since the Arkansas Supreme Court left unclear whether the law banned merely mentioning evolution, teachers could not know what conduct was forbidden.
How the Court got there
The legal reasoning, step by step
- The Court explained that the First Amendment, applied to the states through the Fourteenth Amendment, requires government to stay neutral among religions and between religion and non-religion — it cannot favor or attack any religious viewpoint.
- The Court traced this neutrality principle through prior cases like Everson v. Board of Education and McCollum v. Board of Education, which held government cannot use public resources or schools to aid or oppose religious belief.
- Applying the purpose-and-effect test from Abington School District v. Schempp, the Court asked whether the law's purpose or primary effect was to advance or inhibit religion; if either was, the law exceeded the government's constitutional power.
- The Court found that Arkansas's law had no purpose other than protecting a particular religious reading of the Book of Genesis from a scientific theory seen as conflicting with it, since the law banned only the teaching of human evolution rather than any broader curricular judgment.
- Because the law singled out a scientific theory for suppression solely due to its perceived conflict with one religious doctrine, the Court concluded it failed the neutrality requirement and could not stand under either possible reading of what the law actually prohibited.
Doctrinal impact
Cases affected by this decision
Reaffirms Everson v. Board of Education (330 U.S. 1)
The Court relied on Everson's rule that government cannot pass laws aiding or preferring one religion over another.
Reaffirms Abington School District v. Schempp (374 U.S. 203)
The Court applied Schempp's test asking whether a law's purpose or effect is to advance or inhibit religion.
Distinguishes Meyer v. Nebraska (262 U.S. 390)
The Court declined to rely on this broader due-process precedent, resolving the case on narrower First Amendment grounds instead.