Lama Tsongkhapa's text In Praise of Dependent Origination deals with one of the two complimentary main concepts in the Prasangika Madhyamika school of Indo-Tibetan philosophy: Emptiness and Dependent Arising. The first concept is that of śūnyatā which is usually translated as "emptiness" or "voidness", and the second is that of Pratītyasamutpāda which is usually translated as "dependent arising", or "dependent origination".
One of Lama Tsongkhapa’s greatest insights was his understanding of emptniess to mean dependent arising and dependent arising to mean emptiness. Emptniness leaves no ways of establishing or proving the existence of something. Specifically, in the context of the Prasangika Madhyamaka tenet system, emptniess is the total absence of the existence of something being established by virtue of anything on its own side. The existence of something can only be established by virtue of dependent arising.
This is the understanding that any phenomenon ‘exists’ only because of the ‘existence’ of other phenomena in an incredibly complex web of cause and effect covering time past, time present and time future. This concept of a web is symbolized by Indra's net, a multidimensional spider's web on which lies an infinite amount of dew drops or jewels, and in these are reflected the reflections of all the other drops of dew ad infinitum.
Stated in another way, the idea is that everything depends on everything else. For example, an individual depends on everything around themselves to exist, conversely, everything depends on an individual to exist. This is because the universe is one example in that, its causes and effects produce an individual or entity; any other way and the universe would not be the same one.
> Short Biography of Lama Tsongkhapa
