"It has been shown that there are two sorts of objects
apprehended by sight, each whereof has its distinct magnitude
or extension: the one properly tangible, _i.e._ to be
perceived and measured by touch, and not immediately falling
under the sense of seeing; the other properly and immediately
visible, by mediation of which the former is brought into
view."--§ 55.

But how are we to reconcile these passages with others which will be
perfectly familiar to every reader of the "New Theory of Vision "? As,
for example:--

"It is, I think, agreed by all, that distance of itself, and
immediately, cannot be seen."--§ 2.

"Space or distance, we have shown, is no otherwise the object
of sight than of hearing."--§ 130.

"Distance is in its own nature imperceptible, and yet it is
perceived by sight. It remains, therefore, that it is
brought into view by means of some other idea, that is itself
immediately perceived in the act of vision."--§ 11.

"Distance or external space."--§ 155.

The explanation is quite simple, and lies in the fact that Berkeley
uses the word "distance" in three senses. Sometimes he employs it to
denote visible distance, and then he restricts it to distance in two
dimensions, or simple extension. Sometimes he means tangible distance