Before revision: The nonuniqueness of solutions of linear rational-expectations models is explainedand resolved. In the stochastic, discrete-time,  constant-coefficients case, the associated free parameters are shown to be the initial values of the impulse responses of expectation terms.
After revision: The nonuniqueness of rational expectations is explained: in the stochastic, discrete-time, constant-coefficients case, the associated free parameters are shown to be the initial values of the impulse responses of expectation terms.