Psychology is generally considered to be the science of mind, although
more properly it is the science of mental states—thoughts,
feelings, and acts of volition. It was formerly the custom of writers
on the subject of psychology to begin by an attempt to define and
describe the nature of mind, before proceeding to a consideration
of the subject of the various mental spates and activities. But more
recent authorities have rebelled against this demand, and have
claimed that it is no more reasonable to hold that psychology
should be held to an explanation of the ultimate nature of mind
than it is that physical science be held to an explanation of the ultimate
nature of matter.
