The hydrophobic effect is behind the observation that oil and water don't mix, and is perhaps the most
important single factor in the organisation of living matter into complex structures like membranes and
organelles. As yet this phenomenon lacks an explanation. We propose such an explanation, based on a
successful theory that accounts for the ubiquitous presence of hydroxide ions at aqueous hydrophobic
interfaces. The effect is caused by suppression of the dipole moment fluctuations of the water molecules
around a hydrophobic solute. By extension this accounts for the coalescence of oil drops. We propose
experiments and calculations to test this novel and quantitative explanation of the hydrophobic effect.