Interesting. Another (comparable but slightly different) classification has been proposed by A. Maslow: http://en.wikipedia.org/wiki/Maslow%27s_hierarchy_of_n

Interesting. Another (comparable but slightly different) classification has been proposed by A. Maslow: http://en.wikipedia.org/wiki/Maslow%27s_hierarchy_of_needs http://en.wikipedia.org/wiki/Maslow%27s_hierarchy_of_needs What is quite tricky is that you can achieve the high levels of the pyramid but still have trouble being ok with the first levels.