distinct from the Hegelian 'totality'. I said (and this thesis only repeats famous propositions of historical materialism) that Marx conceived the structure of every society as constituted by 'levels' or 'instances' articulated by a specific determination: the infrastructure, or economic base (the 'unity' of the productive forces and the relations of production) and the superstructure, which itself contains two 'levels' or 'instances': the politico-legal (law and the State) and ideology (the different ideologies, religious, ethical, legal, political, etc.).

Besides its theoretico-didactic interest (it reveals the difference between Marx and Hegel), this representation has the following crucial theoretical advantage: it makes it possible to inscribe in the theoretical apparatus of its essential concepts what I have called their respective indices of effectivity. What does this mean?

It is easy to see that this representation of the structure of every society as an edifice containing a base (infrastructure) on which are erected the two 'floors' of the superstructure, is a metaphor, to be quite precise, a spatial metaphor: the metaphor of a topography [topique]. ⁵ Like every metaphor, this metaphor suggests something, makes something visible. What? Precisely this: that the upper floors could not 'stay up' (in the air) alone, if they did not rest precisely on their base.

Thus the object of the metaphor of the edifice is to represent above all the 'determination in the last instance' by the economic base. The effect of this spatial metaphor is to endow the base with an index of effectivity known by the famous terms: the determination in the last instance of what happens in the upper 'floors' (of the superstructure) by what happens in the economic base.

Given this index of effectivity 'in the last instance', the 'floors' of the superstructure are clearly endowed with different indices of effectivity. What kind of indices?

It is possible to say that the floors of the superstructure are not determinant in the last instance, but that they are determined by the effectivity of the base; that if they are determinant in their own (as yet undefined) ways, this is true only in so far as they are determined by the base.

Their index of effectivity (or determination), as determined by the determination in the last instance of the base, is thought by the Marxist tradition in two ways: (1) there is a 'relative autonomy' of the superstructure with respect to the base; (2) there is a 'reciprocal action' of the superstructure on the base.

We can therefore say that the great theoretical advantage of the Marxist topography, i.e. of the spatial metaphor of the edifice (base and superstructure), is simultaneously that it reveals that questions of determination (or of index of effectivity) are crucial; that it reveals that

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