In too many topics, too little time of June 29, 2003, regarding the role of the actor in the actor-network theory and methodology, jeremy writes:
"however, the fixation on the actor is still present. get rid of it, stop thinking about it, think about networks, only networks, and then think about how it constructs the actor, then i think you have a theoretically interesting actor-network theory."
To take the actor-network theory to explain the construction of the actor only would provide a one sided elaboration and perhaps incomplete picture of the relationship between the actors and the network. It is true that a particular network can be treated as an actor (a complex one). However, in the actor-network discourse it is understood that a set of actors interconnected amongst themselves through their links create a network (or a topology). Needless to say, an actor can be part of many networks/topologies at the same time, manifesting itself differently within a particular network.
While networks do have a major role in the process of actor construction, it is also true that actors play a decisive role in the construction of the networks that they are part off, and must be taken into consideration. It is obvious that human actors are not solely constructions by the pertinent networks. Human actors do have intrinsic properties that are not constructible and changeable by the networks/topologies.
This is little bit trickier for non-human actors and it can be claimed that all non-human actors related to information technology (IT) are constructions since they are man made. True, however, we should not forget that information technology actors are mostly used by those who had no say in their construction. Thus, when IT actors are used in networks/topologies other then those that constructed them, they influence and change those networks within which they are imbedded and used.
Even the process of the IT actor construction is not purely one way (i.e. networks construct the actor). In the process of actor construction networks change and are modified along the way (some due to the actors) to finally construct an actor that almost always is different than what was originally though at the beginning of the construction process.
So, yes, actors are constructed, but they also construct the networks. It is an iterative process.
Related:
Defining the ingredients of actor-network and open-content open-communication

