excogitate
     v 1: come up with (an idea, plan, explanation, theory, or
          priciple) after a mental effort; "excogitate a way to
          measure the speed of light" [syn: {invent}, {contrive},
          {devise}, {formulate}, {forge}]
     2: reflect deeply on a subject; "I mulled over the events of
        the afternoon"; "philosophers have speculated on the
        question of God for thousands of years"; "The scientist
        must stop to observe and start to excogitate" [syn: {chew
        over}, {think over}, {meditate}, {ponder}, {contemplate},
        {muse}, {reflect}, {mull}, {mull over}, {ruminate}, {speculate}]
Source: WordNet® 2.0