Descartes used the term "intuition" to mean the way by which an innate idea is known.
That is an idea that is understood or self-sufficient.
It needs no outside experience to make it evident.
Descartes goes beyond basic facts to say that certain ethical principles are intuitive.
The best example of this is a basic belief that murder is morally wrong.
He does not however imply that all knowledge is intuitive.
Descartes uses the term "deduction" to mean the process for developing ideas other than those that are innate.
This includes putting multiple innate ideas together with learned or deduced ideas to form new ones.
According to Descartes all ideas come from one of these two sources.
John Locke disagreed with Descartes on this.
He rejected outright the theory that any one idea is or can be innate.
He says that a far simpler explanation is that all ideas are learned from experience.
One of the arguments for intuition is that some truths are universally understood and must therefore be innate.
Locke combats this by pointing out that a truth being universal does not necessitate its being innate, it could have been learned by all people.
He goes on to say that there is no universal idea because it is not known to infants or the mentally impaired.
The intuitionists (Descartes' cronies) then argue that these ideas are universal to men who have "come to the use of reason.
" Locke points out then that this is a contradiction for, if reason is used to find an idea it cannot be innate.