古代西方哲学家认为构成自然界的物体并衍生万物的物质是水、火、地、风四大元素。地球依着黄道运行其实就是四大元素的流转变化，因此将黄道12星座分为四类。
there are two classifications of the signs of the zodiac —— elements and qualities——and they each refer to core human characteristics. the elements， which are also known as triplicities （as in groupings of three）， speak to the basic nature and temperament of a sign， whereas qualities address their manner of expression.
the elements （fire， earth， air and water） are based on ancient greek philosophy. the ancients took it back to square one， the building blocks of life： the solid earth upon which we stand， the running water we use as a resource， the air we breathe and the fire which keeps us warm and aids in the creation of additional resources. it's easy to see a kinship to science in this elemental plan.
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