[1][2] Turing defined the class of unorganized machines as largely random in their initial construction, but capable of being trained to perform particular tasks.
In correspondence with William Ross Ashby in 1946 he writes: I am more interested in the possibility of producing models of the action of the brain than in the applications to practical computing...although the brain may in fact operate by changing its neuron circuits by the growth of axons and dendrites, we could nevertheless make a model, within the ACE, in which this possibility was allowed for, but in which the actual construction of the ACE did not alter, but only the remembered dataIn his 1948 paper Turing defined two examples of his unorganized machines.
The first were A-type machines — these being essentially randomly connected networks of NAND logic gates.
The purpose of the connection modifiers were to allow the B-type machine to undergo "appropriate interference, mimicking education" in order to organize the behaviour of the network to perform useful work.
[3] Turing claimed that the behaviour of B-type machines could be very complex when the number of nodes in the network was large, and stated that the "picture of the cortex as an unorganized machine is very satisfactory from the point of view of evolution and genetics".