700,000-Year-Old Stone Tools Point to Mysterious Human Relative

Zeronowhere: On the context of Marx's 'I am not a Marxist' quote: "As far as I know, the MIA cites it as opposing Guesde on the matter of the economic section of the program for the French Workers' Party...

...(the section was written by Guesde, and mainly, though not entirely, approved of by Marx). However, as far as I know, the quote is only found quoted by Engels, and I can only find it in two documents:

Now what is known as ‘Marxism’ in France is, indeed, an altogether peculiar product—so much so that Marx once said to Lafargue: ‘Ce qu'il y a de certain c'est que moi, je ne suis pas Marxiste.’ -Letter to Bernstein, 1882.

And if this man has not yet discovered that while the material mode of existence is the primum agens this does not preclude the ideological spheres from reacting upon it in their turn, though with a secondary effect, he cannot possibly have understood the subject he is writing about. However, as I said, all this is secondhand and little Moritz is a dangerous friend. The materialist conception of history has a lot of them nowadays, to whom it serves as an excuse for not studying history. Just as Marx used to say, commenting on the French 'Marxists' of the late [18]70s: 'All I know is that I am not a Marxist.'-Letter to Schmidt, 1890...