If we put the MC-IC and the Ascendant-Descendant axes together, the two tend to form a cross in the chart. This cross is often taken to signify the “cross of matter” – the four points where we are pinned down in the physical world of incarnation. The Ascendant-Descendant axis fixes ‘self’ and ‘other’, whilst the MC-IC axis fixes inner – subjective – and outer – objective – reality.
In symbolic terms, the Midheaven is where you want to shine like the sun at noon – your public outer self – and the IC is where you go deep within to draw nourishment and find your centre – your private or innermost self. Taken as an axis, the IC-MC shows life direction: the IC represents where you are coming from and the MC where you are going.