"Thinking" is rather an abstract term, and little understood. There has been much progress in neuroscience, brain anatomy and physiology, but this is little help to teachers looking to improve the teaching and learning process. One of my favourite adages is Keep It Simple (KIS), and to this end it is helpful to reduce all the thinking about thinking to one key idea.
There are three categories of thinking: logical, critical and creative. Each of these thinking processes differs slightly in its methodology and certainty, so if teachers recognise the different chains of thought then they can reinforce these processes and teach pupils how to make the most of them.
Logical thinking tends to follow the laws of propositional logic, and forces you into a conclusion that is either unavoidable or highly probable, such as "If this is so, then that must follow."
Wherever we have laws and algorithms that establish "givens" or facts, then we should be able to deduce logical certainties and probabilities. This is particularly apparent in physics and maths, for example in calculations of voltage, resistance or angles. This principle can also apply to everyday teaching and provide teachers with the opportunity to praise and reinforce this form of reasoning.
Critical thinking tends to produce less certain conclusions, where possibilities are based on the evidence and logical inference. Judgment is the key to the final stage of this thinking process. Pupils must decide which inference is "more likely than not", and then proceed with that line of reasoning. This is a vital intellectual process across all subjects, but perhaps more clearly illustrated in the inquiry aspects of the curriculum, such as history or geography. Again we can praise and reinforce this form of reasoning throughout our teaching.
Creative thinking tends to produce less certain conclusions. The philosopher Edward de Bono named it lateral thinking and our American cousins refer to "from left field". In its less innovative form, teachers would recognise it as imagination. It is a vital intellectual process we normally associate with literature rather than science. However, it is interesting to note how many discoveries have been arrived at this way. Einstein's "thought experiments", where he imagined himself riding on a beam of light are an example. Teachers need to illustrate how it can be useful to look for alternatives and think around problems.
Alan Haigh is the author of The Art of Teaching: Big Ideas, Simple Rules (Pearson).