First published in 2000. This is Volume I of eight in the International Library of Philosophy looking at the area pf philosophy of Mind an Language. Written in 1927, Dialectic is a convenient technical name for the kind of thinking which takes place when human beings enter into dispute, or when they carry on in reflection the polemical consideration of some theory or idea. This text is an attempt to examine the circumstances and conditions of controversy in order to understand what are its inescapable limitations, its intellectual traits and values.