against Bain’s genetic space-theory.  Stumpf’s famous criticism applies not only to Bain, but also to the other English empiricists and to Wundt.  Bain says:  “When with the hand we grasp something moving and move with it, we have a sensation of one unchanged contact and pressure, and the sensation is imbedded in a movement.  This is one experience.  When we move the hand over a fixed surface, we have with the feelings of movement a succession of feelings of touch; if the surface is a variable one, the sensations are constantly changing, so that we can be under no mistake as to our passing through a series of tactual impressions.  This is another experience, and differs from the first not in the sense of power, but in the tactile accompaniment.  The difference, however, is of vital importance.  In the one case, we have an object moving and measuring time and continuous, in the other case we have coexistence in space.  The coexistence is still further made apparent by our reversing the movement, and thereby meeting the tactile series in the inverse order.  Moreover, the serial order is unchanged by the rapidity of our movements."[21]

   [20] Stumpf, K., ’Ueber d. psycholog.  Ursprung d. 
   Raumvorstellung,’ Leipzig, 1873, S. 54.

   [21] Bain, A., ‘The Senses and the Intellect,’ 3d ed., New
   York, 1886, p. 183.

Stumpf maintained in his exhaustive criticism of this theory, first, that there are cases where all of the elements which Bain requires for the perception of space are present, and yet we have no presentation of space.  Secondly, there are cases where not all of these elements are present, and where we have nevertheless space presentation.  It is the first objection that concerns me here.  Stumpf gives as an example, under his first objection, the singing of a series of tones, C, G, E, F. We have here the muscle sensations from the larynx, and the series of the tone-sensations which are, Stumpf claims, reversed when the muscle-sensations are reversed, etc.  According to Stumpf, these are all the elements that are required by Bain, and yet we have no perception of space thereby.  Henri[22] has pointed out two objections to Stumpf’s criticism of Bain’s theory.  He says that Bain assumes, what Stumpf does not recognize, that the muscle sensations must contain three elements—­resistance, time, and velocity—­before they can lead to space perceptions.  These three elements are not to be found in the muscle sensations of the larynx as we find them in the sensations that come from the eye or arm muscles.  In addition to this, Henri claims that Bain’s theory demands a still further condition.  If we wish to touch two objects, A and B, with the same member, we can get a spatial experience from the process only if we insert between the touching of A and the touching of B a continual series of tactual sensations.  In Stumpf’s instance of the singing of tones, this has been overlooked.  We can go from the tone C to the tone F without inserting between the two a continuous series of musical sensations.