Completely agree about the need for theory to evolve with material changes.

Science needs to advance, but does it follow that every individual leftist needs to be preoccupied with theory, with becoming a scientist? For every Lenin there were millions of average people trusting in the party line that he and the Bolsheviks produced. Most Russian revolutionaries, of whom only a fraction were serious party members, likely did not have a strong grasp of theory outside of their own experience.

Western leftists (myself included) have to combat their latent liberalism, one form of which is a belief in the "marketplace of ideas." This belief is the basis of electoralism, which as most lefitsts understand theoretically, is ineffectual in practice. Yet with so much emphasis on perfecting science, one has to wonder if the Western left has actually internalized the truth that the best idea does not inevitably win, that progress doesn't follow inevitably from worsening material conditions.

We could have a perfect theoretical understanding of capitalism and it would not matter until the left has politically organized in such a way as to put that theory into practice. There are enough theorizers/philosophers/"scientists" on the left and not enough direct action and organizing.

Reading the abstract theory of Marx, Engels, Lenin, and Mao — it is too easy to forget the context in which those writings happen. Many believe that Marx invented communism, but his actual result was consolidating an otherwise disorganized proletarian movement under a single theoretical basis.

The manifesto itself was written intentionally watered down on some points so as to receive buy-in from various socialist factions. The intellectual disagreements between the factions worked themselves out because the correctness of this or that idea was demonstrated in practice. Engels wrote in his 1888 preface to the manifesto,

Marx, who drew up this programme to the satisfaction of all parties, entirely trusted to the intellectual development of the working class, which was sure to result from combined action and mutual discussion. The very events and vicissitudes in the struggle against capital, the defeats even more than the victories, could not help bringing home to men’ s minds the insufficiency of their various favorite nostrums, and preparing the way for a more complete insight into the true conditions for working-class emancipation. And Marx was right. The International, on its breaking in 1874, left the workers quite different men from what it found them in 1864. Proudhonism in France, Lassalleanism in Germany, were dying out, and even the conservative English trade unions, though most of them had long since severed their connection with the International, were gradually advancing towards that point at which, last year at Swansea, their president [W. Bevan] could say in their name: “Continental socialism has lost its terror for us.” In fact, the principles of the Manifesto had made considerable headway among the working men of all countries.

Leftist theory does need to advance, but not through contemplation alone. It needs to be tested in practice. And I think that is what JT is saying here, that theoretical correctness is secondary to direct action.