Extract from Vladimir Ilyich Lenin, What Is To Be Done?: BURNING QUESTIONS of our MOVEMENT. (1901), the text that set the scene for the Russian Revolution (and the splintering of the Bolsheviks/Mensheviks).
“Without revolutionary theory there can be no revolutionary movement. This idea cannot be insisted upon too strongly at a time when the fashionable preaching of opportunism goes hand in hand with an infatuation for the narrowest forms of practical activity. Yet… the importance of theory is enhanced by three other circumstances, which are often forgotten: first, by the fact that our Party is only in process of formation, its features are only just becoming defined, and it has as yet far from settled accounts with the other trends of revolutionary thought that threaten to divert the movement from the correct path… Under these circumstances, what at first sight appears to be an “unimportant” error may lead to most deplorable consequences, and only short-sighted people can consider factional disputes and a strict differentiation between shades of opinion inopportune or superfluous. [Our fate] for very many years to come may depend on the strengthening of one or the other “shade”.”
from Dogmatism And “Freedom of Criticism”