  The notions of cause and effect are widely employed in science. I discuss why
and how they are rooted into thermodynamics. The entropy gradient (i) explains
in which sense interventions affect the future rather than the past, and (ii)
underpins the time orientation of the subject of knowledge as a physical
system. Via these two distinct paths, it is this gradient, and only this
gradient, the source of the time orientation of causation, namely the fact the
cause comes before its effects.
