I introduced this term in my book 'PARALLEL THINKING' (published by Viking, London and Penguin Books, London).
Parallel thinking is best understood in contrast to traditional argument or adversarial thinking.
With the traditional argument or adversarial thinking each side takes a different position and then seeks to attack the other side. Each side seeks to prove that the other side is wrong. This is the type of thinking established by the Greek Gang of Three (Socrates, Plato and Aristotle) two thousand four hundred years ago.
Adversarial thinking completely lacks a constructive, creative or design element. It was intended only to discover the 'truth' not to build anything.
With 'parallel thinking' both sides (or all parties0 are thinking in parallel in the same direction. There is co-operative and co-ordinated thinking. The direction itself can be changed in order to give a full scan of the situation. But at every moment each thinker is thinking in parallel with all the other thinkers. There does not have to be agreement. Statements or thoughts which are indeed contradictory are not argued out but laid down in parallel.In the final stage the way forward is 'designed' from the parallel thought that have been laid out.
A simple and practical way of carrying out 'parallel thinking' is the Six HatsTM method which is now being used widely around the world both because it speeds up thinking and also because it is so much more constructive then traditional argument thinking.
Information on Lateral Thinking and Six HatsTM methods are available on this website. Particulars of training courses are also given.
Edward de Bono