Althusser writes on this concept, which is based on the Engels’s letter to Bloch in 21 September, 1890 that: “it is clear that we have now found a basis and an origin for this force that triumphs in the last instance: determination by the economy is no longer external to the accidents amid which it asserts itself, it is the internal essence of these accidents” (Althusser 2005, 112–113; 121).