The arrow shows us motion, it infers time. Imagine that time is not a movement inferred by the arrow, but it is the form of the arrow itself. It is an integral part of the space you inhabit. Before the beginning there was no end, all time occurred at a single point, that single (dimensionless) point contained all space. Unity, perfection, God.
The fall was the creation of duality, in enthalpy and entropy, mass and energy, time and space, man and god. At the point of mitosis the separation becomes endless and infinite, the single point becomes irrelevant and forgotten. Man’s grasp of the spatial dimensions is well developed; however, time, entropy, energy and chaos are still poorly defined without the endless equations of Arcana Physika.
The arrow enables us to infer flux, the flow of mass (or space) through (with) time. The sigil of time is unnoticed but so necessary for man to exist, as he does, as a temporal being.
Chronos -> Cronus -> Saturn
What is the esoteric meaning of the arrow, how did it come to be? The arrow in astrology -> means action rather than physicality (e.g. Mars – action over divine spirit).