Noetic pluralism, 111. How our knowledge grows, 112. Earlier ways of thinking remain, 113. Prehistoric ancestors discovered the common sense concepts, 114. List of them, fig-5) They came gradually into use, 116. Space and time, 118. 'things,' 118. Kinds, 119. 'cause' and 'law,' 119. Common sense one stage in mental evolution, due to geniuses, 120. The 'critical'