> (3) Rule discovery, the generation of plausible hypotheses, centers on the use of tested building blocks.  Past experience is directly incorporated, yet innovation has broad latitude.
>The particular methods of recombining building blocks draws heavily on genetics, but it can be considered as an abstract version of a pervasive process.  We can describe nerophysiological theories of thought in terms of building blocks.  In Hebb’s classical theorem, a cell assembly is a set of a few thousand interconnected neurons capable of self-sustained reverberation.  A cell assembly operates somewhat like a small cluster of rules that is coupled via common tags.
>Cell assemblies act in parallel, broadcasting their messages (pulses) widely via a large number of synapses (interneuron contacts.  A single neuron may have as many as ten thousands synapses). 
>Cell assemblies compete for neurons via recruitment (adding parts of other cell assemblies) and fractionation (dividing into fragments that serve as offspring).
>It is not difficult to see this as a process that recombines tested building blocks.  Moreover, cell assemblies can be integrated into larger structures called phase sequences.  Indeed, it is not difficult, on rereading Hebb to see counterparts of all the processes we have discussed.