Stuart, in order to talk about the "outside" world in contrast to some solipsistic consciousness, you must first assume that consciousness is bounded. There is no evidence for this.

Mind is bounded, but consciousness is different.

In your initial comment and your follow up responses, you've made a host of unconscious assumptions which Casper is pointing to. If you re-read your comments in light of conscious experience (which is, like 99% of what exists, not amenable to measurement) you'll get a clearer idea of what he is pointing to.

The power of the scientific method is in its exclusive focus on what can be measured. The delusion of the faith of scientism is that only what can be measured exists.

This may be one of those fake Einstein quotes, but whether it was him or someone else, it sums up the problem quite beautifully:

Not everything that can be counted counts. And not everything that counts can be counted.