Several years ago an ancient paper regarding the relationship between theory and practice originally writen by a chinese politician and educator was re-written with emphasis to Geology to support teaching activities. Since that time it has been applied to post-graduate activities. The adapted text is presented and discussed. It stresses the knowledge levels developed by man in studying nature as well as the importance of field work to geology work. It is emphasized that field practices are needed not only to allow students to improve their understanding of the external dynamics of the Earth's crust but also to allow them to rediscover the theoretical paths used to reconstruct the Earth's geologic evplution. The entwinning between theory and practice, as examplifïed by natural dynamics, follows the cyclic evolution of scientifïc knowledge, along a continuous and permanent recurrence.
