Neuroscience, like genomic science creates new ways of harming, as well as helping, people. However, this paper argues, these are unlikely fundamentally to challenge the reasons to value privacy, or our ability to protect it for the foreseeable future. Rather, the main threat to privacy comes from the difficulty of determining its nature and value. Hence, this paper looks at the philosophical difficulties in understanding the value of privacy, and shows how we can use the justification of the secret ballot in democratic societies to illuminate the importance of privacy to people's freedom and equality. It shows that the value of privacy has implications for the procedural, as well as substantive, aspects of neuroethics, and concludes that the threats neuroscience poses to privacy highlight the importance of the humanities and social sciences to the ethical use and development of neuroscience.