First stop on the soul’s trip was the Halls of Ma’ati, where the dead person’s heart would be weighed on a two-armed scale of the kind used in Ancient Egypt for weighing gold and jewels.
Ma’ati meant Double Ma’at — double not in the evil-twin sense of “double,” but in the times-two sense — double strength. As for Ma’at, she was a goddess, sometimes pictured as two goddesses, or a pair of twins — teenage twins, with wings on their shoulders and ostrich feathers in their headdresses.
She was one of the presiding deities at the weighing of the heart, the others being jackal-headed Anubis, who did the actual weighing, and ibis-headed Thoth, moon god and thus, in a society that used the lunar calendar, the god of time. He was also the god of measurements and numbers and astronomy and engineering skills, and in addition he was a supernatural scribe or clerk. In heart-weighing scenes, he’s often shown with his wax tablet at the ready and his stylus poised, just as a scribe would have been present at a real-life gold-weighing to record the results.
Sometimes a miniature Ma’at was shown sitting on one pan of the scales, but more often it was her feather — the feather of Ma’at — that was used to counterweight the heart. If your heart weighed the same as Ma’at, you could go on to the next stage and meet and merge with Osiris in his guise as god of the Underworld, where a suitable underworldly location would be assigned to you, with possibilities for rebirth. (The Egyptian inner coffin was known, reassuringly, as “that which begets,” and the coffin-board was known as “the egg”— so you might hatch out of death, just like a bird.)
However, if your heart was heavier than the feather, it would be thrown to an unpleasant crocodile-headed deity, which would eat it. As with most mythologies or religions, there was a way around this moment of dreadful judgement: you could fortify your heart ahead of time with special charms obliging it not to snitch on you. Presumably the heart was willing to co-operate, since it would be better for both of you if your heart kept your dirty deeds to itself: being eaten by a crocodile was not in either of your best interests. On the other hand, your cheatin’ heart might tell on you. The uncertainty must have been what made the drama of post-mortem heart-weighing such a riveting subject for speculation among the Ancient Egyptians.
Why was it Ma’at who was used as the counterweight to the heart? Ma’at was a goddess, but she wasn’t a goddess with a specific function or area, such as writing or fertility or animal husbandry: she was much more important than that. The term ma’at meant truth, justice, balance, the governing principles of nature and the universe, the stately progression of time — days, months, seasons, years. It also meant the proper comportment of individuals toward others, the right social order, the relationship between the living and the dead, the true, just, and moral standards of behaviour, the way things are supposed to be — all of those notions rolled up into one short word. Its opposite was physical chaos, selfishness, falsehood, evil behaviour — any sort of upset in the divinely ordained pattern of things.
This concept — that there is an underlying balancing principle in the universe, according to which we should act — appears to have been almost universal.
excerpt from Margaret Atwood – Payback