Spatial laboratory for Landscape Design!

If the enclosed garden has "the character of an interior," How is it possible that it can also serve as a "spatial laboratory for landscape design?"


Reading - The Enclosed Garden (Rob Aben & Saskia de Wit)
A garden is enclosed in the fact that it has its own individual surroundings and elements that make it a garden in its self. And I suppose this does make it have its own interior. Again there will always be the outside design, where ever the garden is in the world it will always have a context - landscape design. Referring to the reading the quote ‘Just this compactness and scale makes the enclosed garden suitable for an outdoor room where one can engage with nature.’ - A spatial laboratory perhaps.
I’m not sure I completely understand the author of this reading and to me most of it is opinion because all gardens of cause are different and therefore his points don’t relate to everywhere, although a very interesting thought to think this way. However i not keen and dont feel i could speak on relationship with the landscape and garden in this much depth, we could say, to have a say in quotes like this.

Me personaly i do think the words interior and laboratory do in some ways relate to the landscape and surroundings almost definatly.