"This is why the meaning of free spiritual production cannot be understood in an idealistically absolutized sense, no matter how great the temptation might be to do so. For even in the work of the greatest intellectual figures be they creative artists or theoreticians [… it] continues to respond […] to the actually given conditions by making its own significant impact upon the emerging transformations of the existent. Nonetheless 'free spiritual production' is free in the genuine sense – and for the same reason also carries a great responsibility as an intellectual enterprise – precisely in the virtue of its undeniable active role in intervening, for better or worse in the unfolding historical process of which it is an integral part."
The article is the 4.1 chapter "Material Transformations and Ideological Forms" of the book Social Structure and Forms of Consciousness Vol II by István Mészáros. Monthly Review Press 2011.