Progressive education can be traced back to the works of John Locke and Jean-Jacques Rousseau, both of whom are known as forerunners of ideas that would be developed by theorists such as John Dewey. Considered one of the first of the British empiricists, Locke believed that "truth and knowledge… arise out of observation and experience rather than manipulation of accepted or given ideas".[2]:2 He further discussed the need for children to have concrete experiences in order to learn.