Plurality is essentially defined as your population’s demand of and desire for social reforms and democracy. Think about it: even the name itself implies the meaning—the higher the level of personal input into a society, the higher the level of personal expectation from the government
Consciousness can be defined as your population’s ability to judge what is best for it. Consciousness is what allows segments of your population to see themselves as interest groups, band together, and try to gain a voice in government. If your POPs are not self-conscious, they cannot do this. The higher your population’s Consciousness, the better their political votes reflect their desires. This way, if your population is majority conservative, they are more likely to vote into power a conservative government than a liberal one. Sets and subsets of consciousness come into play, and the political group able to unite the greatest number of subsets (what ever they maybe) will win elections and coups.
Militancy is directly related to Plurality and Consciousness. Under autocratic forms of government, Militancy is increased by Plurality and Consciousness; under democratic forms of government, Militancy is reduced by Plurality and Consciousness.
Odd how a game can get hit the nail right on the head. (http://www.paradoxian.org/vickywiki/index.php/The_Big_Three)