  We study the capacity of active matter to rise in thin tubes against gravity
and other related phenomena, like, wetting of vertical plates and spontaneous
imbibition, where a wetting liquid is drawn into a porous medium. This
capillary action or capillarity is well known in classical fluids and
originates from attractive interactions between the liquid molecules and the
container walls, and from the attraction of the liquid molecules among each
other. We observe capillarity in a minimal model for scalar active matter with
purely repulsive interactions, where an effective attraction emerges due to
slowdown during collisions between active particles and between active
particles and walls. Simulations indicate that the capillary rise in thin tubes
is approximately proportional to the active sedimentation length $\lambda$ and
that the wetting height of a vertical plate grows superlinear with $\lambda$.
In a disordered porous medium the imbibition height scales as $\langle
h\rangle\propto\lambda\phi_m$, where $\phi_m$ is its packing fraction.
