The shape of the table is no better. We are all in the habit of
judging as to the 'real' shapes of things, and we do this so
unreflectingly that we come to think we actually see the real shapes.
But, in fact, as we all have to learn if we try to draw, a given thing
looks different in shape from every different point of view. If our
table is 'really' rectangular, it will look, from almost all points of
view, as if it had two acute angles and two obtuse angles. If
opposite sides are parallel, they will look as if they converged to a
point away from the spectator; if they are of equal length, they will
look as if the nearer side were longer. All these things are not
commonly noticed in looking at a table, because experience has taught
us to construct the 'real' shape from the apparent shape, and the
'real' shape is what interests us as practical men. But the 'real'
shape is not what we see; it is something inferred from what we see.
And what we see is constantly changing in shape as we move about the
room; so that here again the senses seem not to give us the truth
about the table itself, but only about the appearance of the table.

Similar difficulties arise when we consider the sense of touch. It is
true that the table always gives us a sensation of hardness, and we
feel that it resists pressure. But the sensation we obtain depends
upon how hard we press the table and also upon what part of the body
we press with; thus the various sensations due to various pressures or
various parts of the body cannot be supposed to reveal _directly_ any
definite property of the table, but at most to be _signs_ of some
property which perhaps _causes_ all the sensations, but is not
actually apparent in any of them. And the same applies still more
obviously to the sounds which can be elicited by rapping the table.

Thus it becomes evident that the real table, if there is one, is not