For the 17th-century French philosopher Rene Descartes, the proposition "I think, therefore I am" was a statement that confirmed his existence and eventually defined it. But in the 21st-century classroom, his famous phrase is gaining new currency as the foundation of a growing educational movement called Thinking Schools.
In the UK, some 55 establishments have gained Thinking Schools accreditation and more than 100 others are working towards it. About a dozen countries across the world are experimenting with the approach, too, including Malaysia, which has ambitious plans to implement it in all its 10,000 state schools. Clearly, the idea is gaining serious traction. So what exactly is it?
Its roots go back to the late 1990s when research emerged suggesting that teaching children how to think (as opposed to just telling them to think) improved classroom and exam performance. Enthused by the findings, David Blunkett, who was then England's education secretary, strongly promoted the process of "teaching thinking", and for a time the topic was hailed as the "next big thing" in education.
Despite the political support, the concept faltered. Richard Cummins, chief executive of Thinking Schools International, a partnership between UK- and US-based education companies, says this was because although the "what" had been laid out clearly, the "how" was not defined. Beyond a few narrow approaches by individual academic gurus which secured some limited take-up, Cummins says that no one was offering a whole-school approach.
Or, rather, it seemed that they weren't until Cummins met Gill Hubble, who at the time was associate principal of St Cuthbert's College in Auckland, New Zealand. She had developed a whole-school model that Cummins recognised as a practical way of rolling out the Thinking Schools vision.
To enable wider take-up, Cummins felt that a cohesive and structured approach to the model had to be devised. This came in 2006 in the form of a set of criteria for what would qualify as a Thinking School, developed by Robert Burden, emeritus professor of educational psychology at the University of Exeter in England.
Burden defined a Thinking School as "an educational community in which all members share a common commitment to giving regular careful thought to everything that takes place".
He added: "This will involve both students and staff learning how to think reflectively, critically and creatively, and employing these skills and techniques in the co-construction of a meaningful curriculum and associated activities."
Cummins says the major difference between a Thinking School and a regular school is that, in the former, thinking is an explicit, rather than an implicit part of a student's experience.
"Many schools will say, `Of course we are doing thinking skills', but very often it's all implicit," he says. "Teachers may say to students, `Go away and think about it', but what do they mean by that? How do you think about it? In a Thinking School, students are taught a range of tools and strategies linked to the development of thinking skills and processes."
Some of the tools adopted by schools include Habits of Mind, such as persistence and managing impulsivity, which enable someone to think intelligently about a problem; Thinking Maps, a visual way of teaching cognitive skills; and Community of Enquiry, where children are encouraged to think collaboratively by means of questioning and exploring disagreement.
One UK institution that has enjoyed particular success with the approach is the Rochester Grammar School. Although the selective girls' school had achieved some of the best GCSE and A-level results in its history when it started the process of becoming a Thinking School, executive principal Denise Shepherd says it was lacking in certain areas.
"There was still too much passive learning," she says. "I felt that very often the girls lacked the resilience and the confidence to excel in their learning and to fail sometimes. Not giving up and dealing with failure are very important."
Shepherd says the Thinking School approach has been "transformational" for teaching and learning, and the schools inspectorate, Ofsted, agrees. Its last report on Rochester Grammar, in 2012, said: "When students leave the school, they have not only the qualifications they need to proceed to higher education but also the maturity and independent learning skills that serve them well in their chosen careers and futures."
"It's given students the tools to take on learning themselves," Shepherd explains. "Students learn independently and can use a range of thinking tools to overcome any problems."
Rochester Grammar is not the only school to find success. In 2012, the University of Exeter and Thinking Schools International held a joint survey to evaluate the impact of the Thinking Schools approach. It found that 90 per cent of all accredited schools reported an improvement in the quality of lessons, and 89 per cent said the approach raised attainment.
Despite these results, not everyone is convinced. Daniel T Willingham, professor of psychology at the University of Virginia in the US, says that more research is needed to unequivocally prove the concept works.
"The real evidence - positive or negative - of Thinking Schools would be data showing better outcomes compared with other schools," Willingham says. "Until we have such data, we can look to history for a reasonable guess about the outcome, because explicitly teaching thinking skills is not really such a new idea. There were a number of similar programmes in the 1970s and they showed quite modest pay-offs.
"There are two reasons these programmes are hard to do well. First, most of what we call thinking skills vary by subject. `Good thinking' is not the same in mathematics as it is in history.
"Second, although there are some general principles that cut across subjects - such as `You should have evidence for statements you make, and ask others for evidence, too' - telling students these principles will get them only so far. To execute the desired thinking skill, students need some of the knowledge of the discipline. `Provide evidence' is a good principle, but you actually have to know some science, or history, or whatever, to put that good idea into practice."
While many may agree with this view, plenty of schools and even governments clearly do not. Cummins says he is working in Dubai, South Africa, Ethiopia, Lithuania, Norway, Thailand, India, Turkey and New Zealand to roll out Thinking Schools.
In addition, Malaysia is working to adapt the culture in all its state schools to the Thinking Schools mentality.
"It is going to be difficult to change the culture, but (the Malaysian authorities) recognise that this is an economic imperative as the multinational companies and universities are complaining that, while students are leaving school with good examination results, they do not have the skills to enable them to take their place in employment or higher education," Cummins explains.
And this last point is really the key to the whole model. Cummins concludes: "I think there's a global realisation that we need to better prepare young people for life when they move on after school, and a recognition that they cannot rely on knowledge alone."
The concept of Thinking Schools, which explicitly teach children how to think through strategies and processes, is growing in popularity globally.
For an institution to become a Thinking School, 14 criteria set by the University of Exeter have to be met.
Schools that have adopted the model claim it raises attainment and engagement.
Critics have suggested that the teaching of critical thinking is not possible but plenty of schools around the world are aiming to do just that.