Abstract
This paper develops a challenge to standard libertarian views that is based on an imagined neuroscientificdiscovery that is incompatible with satisfaction of a standard libertarian requirement for mainstream free decision making, and it explores potential libertarian responses to this discovery. The requirement at issue may beformulated as follows: In mainstream cases, an agent freely decided at _t_ to _A_ only if, given the past and the laws of nature, the agent was able right up to _t_ to do something else intentionally at t than decide to _A_. The imagined discovery is about a point of no return for the making of any particular decision in a mainstream scenario.