If you put a hydrophobic substance into a hydrophilic substance, what would happen?
Well usually you get a biphasic system.
What happens when you mix diethyl ether and water, or hexanes and water, or methylene chloride and water, or methanol and hexanes?
Whichever solvent is the denser, will form the lower layer. Biphasic systems are an important means of separation in that a desired solute can be extracted preferentially into either the aqueous or the organic layer.