"And a river went out of Eden to water the garden; and from thence it was parted, and became into four heads. The name of the first is Pison: that is it which compasseth the whole land of Havilah, where there is gold; And the gold of that land is good: there is bdellium and the onyx stone. And the name of the second river is Gihon: the same is it that compasseth the whole land of Ethiopia. And the name of the third river is Hiddekel: that is it which goeth toward the east of Assyria. And the fourth river is Euphrates." Genesis 2:10-14

Andrew Jukes wrote, "It may be said in general that there are four sources of truth, and but four, which are accessible to men, which are like rivers, in the fertility they produce upon their banks, and in the glorious power they all possess of reflecting heaven; first, intuition, by which we get an acquaintance with moral or spiritual things, which are not objects of sense; second, perception, through the senses by which we only get an acquaintance with material things and their properties; third, testimony, by which we learn what others have found out through perception or intuition; fourth, reasoning or reflection, a process of the understanding, by which we unfold what is contained or implied or suggested by the perceptions, intuitions, or testimony."

Pison - Intuition
Gihon - Testimony
Hiddekel - Perception
Euphrates - Reflection