If the feeling of twoness or of oneness is anything but an inference,
why is it that a person can perceive two objects on two fingers which
are some distance apart, but perceives the same two objects as one
when the fingers are brought near together and touched in the same
way? It is difficult to see how bringing the fingers together could
make a sensation any less complex, but it would naturally lead a
person to infer one object, because of his previous associations. He
has learned to call that _one_ which seems to occupy one place. If two
contacts are made in succession he will perceive them as two because
they are separated for him by the time interval and he can perceive
that they occupy different places.

When two exactly similar contacts are given and are perceived as one,
we cannot be sure whether the subject feels only one of the contacts
and does not feel the other at all, or feels both contacts and thinks
they are in the same place, which is only another way of saying he
feels both as one. It is true that when asked to locate the point he
often locates it between the two points actually touched, but even
this he might do if he felt but one of the points. To test the matter
of errors of localization I have made a few experiments in the
Columbia University laboratory. In order to be sure that the subject
felt both contacts I took two brass rods about four inches long,
sharpened one end and rounded off the other. The subject sat with the
palm of his right hand on the back of his left and his fingers
interlaced. I stimulated the back of his fingers on the second
phalanges with the sharp end of one rod and the blunt end of the other
and asked him to tell whether the sharp point was to the right or to
the left of the other. I will not give the results in detail here, but
only wish to mention a few things for the purpose of illustrating the