This paper is based on a presentation made to a conference held October 28-29, 1988, at Cambridge, Massachusetts, on Arms Control Without Negotiation: Unilateral and Independent Initiatives. It describes and discusses the philosophic roots behind the emergence and activities of the antinuclear movement, identifying six major "motivational currents": pacifism, moralism, politics, feminism, anti-establishmentism, and antinuclearism. Although the first four motivational drives play important roles within the overall movement, the latter two--anti-establishmentism and antinuclearism--probably constitute the most far-reaching and persuasive philosophic motivations to be found in the antinuclear protest today. Anti-establishmentism embodies a critical attitude toward the established sociopolitical norms of modern society, including a criticism of the current international security regime, while also embracing a "positive, alternative view" regarding conducting both interpersonal and international relations. Antinuclearism is based mainly on the fear of nuclear war. Together, these motivations help define and refine each other's attitudes towards nuclear arms and provide the philosophic foundation for the antinuclear movement.