2. Philosophy - Stefano Franchi

F ORM AND CONTENT
very word “structure”, derived from the vocabularies of architecture and engineering.
“Structure,” from the Latin structura, is the nominal form of the verb struere, to build, and
literally means the result of the process—namely, con-structing—that produces an orga-
nized, and possibly lawful, arrangement of material. Thus, a structure of concrete, for ex-
ample, is what it is in virtue of both the reciprocal organization of the various beams and
pieces and the materials they are made of. A concrete beam can enter in a relationship with
another one precisely because it is made of (a particular kind of) concrete, not just because
of its size, length, and depth. Were we to change the material substrate—and use playdough
instead of concrete, for example—while keeping the same “structural” organization, we
would obtain a very different structure indeed. It matters so much whether the beams are
made of steel, wood, or playdough, that in fact a different structural organization may be
called for to achieve the same function with different materials.
All this is quite clear, and not particularly surprising, but it is also clear that this sense
of concrete structure is not what might be used by AI and Structuralism. In fact, whether
the chessmen are made of wood or of iron, should not matter too much to the search space
that controls their movements, and similarly the substratum of the myth should not matter
too much to the functioning of the religious structure. When we say that a search space is
a “formal structure” we cannot, therefore, rely on the ordinary meaning of “structure” and
just add the qualifier “formal,” because that qualifier, by suppressing the relevance of the
substratum, takes away one of the elements that defines what a structure is. To put it blunt-
ly: prima facie, the term “formal structure” (or “abstract”, or “detached” structure) is an
oxymoron whose content is empty. To make sense of it, we need to backtrack and try to
understand what we are detaching the structures from, first of all, and whether they can still
work as structures once the detachment has taken place.
As a first approximation, a detached structure can be defined as follows: the material
“substance” of the involved elements can be dispensed with. This definition is very close
to a classical slogan of the Structuralist years: only positions count. In other words, the val-
ue of a term within the system is given by its position with respects to other terms. What
matters are the relations between the terms and not the terms themselves. Thus, a chess-
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