This term also was utilized by the Alchemists to represent their 'Chaos' or 'First Matter'.

It was knowledge of this substance that allowed them to embark upon the journey of discovering the Philosopher's Stone or 'Ultimate Matter'.

As thefez mentions, this is an Aristotlian idea and this most surely found its way into the Western Esoteric Tradition via the Arabic philosophers who in turn took it from the Greeks.

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