Logic circuits provide networks to simulate the functions of neural networks of the brain, and can discriminate degrees of state, and combinations of degrees of state, corresponding to a number of neurons. Logic circuits comprise Recursive AND NOT Conjunctions (RANCs), or AND NOT gates. A RANC is a general logic circuit that performs conjunctions for 2n possible combinations of truth values of n propositions. The RANCs function dynamically, with capabilities of excitation and inhibition. Networks of RANCs are capable of subserving a variety of brain functions, including creative and analytical thought processes. A complete n-RANC produces all conjunctions corresponding to the 2n possible combinations of truth values of n propositions.