I say, friend, that where one is not born, does not age or die, or pass from one state to another, or arise again — that ‘world’s end’ is not to be known, seen or reached by travelling. Yet I say that there is no end of dukkha without reaching world’s end. Rather, it is in this fathom-long body, endowed with perception and mind, that I make known the world, the arising of the world, the cessation of the world, and the way to the cessation of the world. (S.I,62)
The Buddha was fundamentally a meditator who focused primarily on subjective experience rather than objective reality.
Thus while most people understand the world as an external reality, the Buddha understands it through how we perceive and interpret it. This is really the only way in which we can truly come to understand reality, which is actually only a perception and interpretation in our own mind. And, most importantly, it is in our own mind that we can end dukkha.
This underscores the importance of mental development or meditation as the means of realizing the truth of ‘the world’.
This reflection by Ajahn Thiradhammo is from the book, Treasures of the Buddha’s Teaching, (pdf) p. 76. (See book for translation citation.)