 A model that hypothesizes retrocausality and reproduces the consequences of standard quantum theory without violating Lorentz invariance is Sutherland’s (2008, 2015, 2017) causally symmetric version of Bohmian mechanics. This model adds to the standard quantum state \(\psi_i\) of ordinary Bohmian mechanics, which is fixed by an initial boundary condition, an additional quantum state \(\psi_f\), which is fixed by some final boundary condition. An analogue to the “guiding equation” for particle motion in ordinary Bohmian mechanics is derived by Sutherland that is symmetric with respect to these states. The zero-component of the probability current, which is directly related to the probability density, is computed as 