Labor and Contemplation

Marx-Engel's division of material labor from mental labor entails that an activity such as the contemplation of an Idea is a variety of Labor.  However, that classification conflicts with a definition of Labor that seems to govern most Marxist works--'a modification of some matter'.  Furthermore, it prevents Marx-Engels from conceiving a corresponding Class distinction the way Dewey does--that between the Working Class and the Leisure Class.  So, their thesis that the separation of mental labor from material labor is the origin of Division of Labor is not only, as has been previously discussed, poorly grounded, it is systematically incoherent, and undermines some fruitful further development.