Existential knowledge is the knowledge of all living beings in order to sustain life on earth. It is an inherent intelligence that living beings are born with and awareness awakened in the context they are located in. It is an understanding that is internalized instinctively, unconsciously (as though already there); and deepened through observation and exploration by and by.  
Existential knowledge is the basis on which all indigenous knowledge is created. This is why indigenous communities have sustained themselves for thousands of years- their communities are based upon sustaining the existence of life.
In fact, we are all, irrespective of place or time, born with this potential. Depending on the conditions around us as children, this potential is either awakened or damaged. Modernity has created conditions that damage our children- this is expressed in the way that we are damaging the world on a global level.
But more and more the contexts are becoming disconnected from the real natural contexts and instead of awakening, conditions are set for damaging the child. Children are also misled from the real world into the world of words. Language traps them into a make believe two dimensional world. In the name of teaching children, what is being passed on is the codification of what is already provided by Nature around. Similarly, in educating them they are being conditioned to understand the two dimensional world of books and digital screens and in the process causing cognitive rewiring and alienation.