Science cannot adequately explain emotional phenomena such as feeling frustrated, falling in love, or being moved by a painting. Since they cannot be explained by physics, chemistry, or neurophysiology, human emotions must not be physical phenomena. The conclusion follows logically if which one of the following is assumed? ['Nothing that can be felt by only one subject can be studied scientifically.', 'Every physical phenomenon can be explained by physics, chemistry, or neurophysiology.', 'Whatever is not a physical phenomenon is an emotional one.', 'Whatever is not a physical phenomenon cannot be explained by science.']