A fundamental solution resolves one or more fundamental causes of a problem. Fundamental cause is synonymous with root cause. Fundamental solutions operate on the fundamental layer of a problem as shown.
The diagram serves as the analytical activist's Problem Solving Map by mapping out the structure of all difficult problems. Follow the causal chain starting at problem symptoms and you will eventually find fundamental solutions that work.
The hardest part is penetrating the fundamental layer, because without the right analytical tools it is invisible.
The map allows you to navigate your way through a problem to a solution that works. To solve a difficult problem you start your analysis at problem symptoms, drill down to the intermediate causes of the symptoms, and then keep going to the fundamental layer. There you will find the root causes. Once these are identified you can design and test fundamental solutions for resolving the root causes. These solutions will replace the superficial solutions that were previously tried and failed.
Why fundamental solutions are important
Examine this list of popular solutions to the environmental sustainability problem:
The Kyoto Protocol treaty on climate change
The Three Rs of reduce, reuse, recycle
Better pollution laws
Why haven't solutions like these solved the problem? That is the blockbuster question facing all of environmentalism. The movement has promoted solutions like these for over thirty years, with only modest success.
The answer is none of these are fundamental solutions. They are all superficial solutions. All they can to is attempt to solve intermediate causes. Since this does nothing to resolve the root causes causing the intermediate causes, all the above solutions fail, no matter how they are presented or how much effort is put into promoting them or how long they are tried.