Counter factual simply means to consider alternative states of being. The concept will carry different associations in different disciplines. For example in therapeutic contexts, counter factual thinking may work at an individual level to help the client to consider past events in order to suggest alternative modes of behavior; in a critical theory tradition counter factual thinking might suggest more general possibilities for the alternative organisation of human society. In political philosophy counter factual thinking has often been associated with states of nature in classic works of political philosophy including Hobbes, Locke and Rousseau - at least classic in the European tradition. More recently Rawls introduced a counter factual element in thinking about justice. This clip explains that the use of the counter factual was designed to enable us to consider principle of justice behind a ‘veil of ignorance’.

Rawls, J. (1971) A Theory of Justice, Ma, USA: Harvard University Press.