Tiphareth has a kind of converting energy in relation to the other sefirot between form (Yesod) and force (Keter). When one crosses over the Middle Path via Tiphareth one reverses polarity. This is exactly mirrored by actions in the physical world of three-dimensional reality through the law of conservation of energy and mass; when energy/mass is transmuted a "sacrifice" is necessary for a new form/force to come into being.Wikipedia: "Tiphareth is unique amongst the Sephirot as it is connected to all the other Sephirot (except Malkuth and Daath) via the subjective paths of the unconscious...Tiphareth is the middle of the Tree. Five Sefirot surround it: above are Chesed at the right (south) and Gevurah at the left (north); and below are Netzach at the right, Hod at the left and Yesod directly below. Together these six comprise a single entity, Zer Anpin, which is the masculine counterpart of the feminine sefira Malkuth. In certain contexts, Tiphareth alone represents all the sefirot of Zer Anpin, so that the entire Tree appears with only five sefirot: Keter, Chokmah, Binah, Tiphareth, and Malkuth."