Many disciplines are better learned by entering into the doing than by mere abstract study. This is often the case with the most abstract as well as the seemingly more practical disciplines. For example, within the philosophical disciplines, logic must be learned through the use of examples and actual problem solving. Only after some time and struggle does the student begin to develop the insights and intuitions that enable him to see the centrality and relevance of this mode of thinking. This learning by doing is essential in many of the sciences. For instance, only after a good deal of observation do the sparks in the bubble chamber become recognizable as the specific movements of identifiable particles.