How is critical thinking learned?
There is no simple answer to this question that can be applied to consistantly produce critical thinkers. There are a number of reasons for this, including the need for individuals to have adopted an epistemology that is compatable with critical thinking, and the question of precisely which cognitive skills and strategies best reflect critical thinking practices. The relationship between these values and the skills is also a complex one.
Epistemologies tend to develop early in life, formed in relation to the beliefs and values of the social group in which we are raised. As such, critical thinking is not an innate practice as much as it is the result of a combination of social factors that come together as a person grows and develops. The philosophical values that tend to contribute best to critical thinking strategies are those that view all knowledge with some skepticism, regardless of its origin. This places critical thinking at odds with philosophies that elevate some bodies of knowledge to being dogmatic and beyond question. Additionally, many logical fallacies arise out of the social instincts we are all born with. It's difficult to avoid seeing positive correlations between the accuracy of information and our personal affection for a friend or relative.
From a young age, many people are taught that being wrong is something to avoid. This is typically done with the best intentions, encouraging children to seek out the 'correct' answer through discouraging them to settle on the 'incorrect' one. However, the result is often the establishment of a value that states possessing incorrect information is a bad thing. Consequently, beliefs are openly defended for fear of being seen as wrong. Once again, such values conflict with those required for critical thinking, which relies on the ability to view information as right or wrong without fear of personal judgement.
The development of such values that are compatible with critical thinking is crucial to its practice in later years. While it's possible for an adolescent or young adult to learn critical thinking strategies, often the results aren't long-lasting.
It is difficult to outline a complete list of the strategies that form the core practice of critical thinking. To mention and describe all of the skills mentioned by even a small selection of academics would take several pages, and serve little purpose. Undoubtedly some would be arguable, and in any case many would feel that the list was incomplete or lacked some significant detail. Most of it would be shared by the skill sets described in any given science curriculum, highlighting the link between critical thinking and scientific reasoning. In any case, the skills, strategies and content which promotes critical thinking in an individual can be learned almost anywhere, arising from an interest in the relationship between good information and the contextual clues that describes it.
Keeping these points in mind, it is possible to teach a percentage of people to think critically. Knowing how to do this effectively and efficiently continues to be a point of discussion.