If there's no truth to the matter of what's out there or how the world is, then I invite you to leave your 10th floor apartment via the window some time. After all, there's nothing out there that makes this dangerous.
Truth cannot be out there—cannot exist independently of the human mind—because sentences cannot so exist, or be out there. The world is out there, but descriptions of the world are not. Only descriptions of the world can be true or false. The world on its own—unaided by the describing activities of humans—cannot.
-- Richard Rorty
The point is not that the world does not behave in consistent ways: the point is that if you assume there is some objective truth 'out there', you are bound to sometimes end up with 'wrong' conclusions, because truth is only in us, because 'truth' is not an attribute that 'what is out there' has.
