But how, it may be asked, can association produce a space-quality not in the things associated? How can we by induction or analogy infer what we do not already generically know? Can 'suggestions of experience' reproduce elements which no particular experience originally contained? This is the point by which Helmholtz's 'empiristic' theory, as a _theory_, must be judged. No theory is worthy of the name which leaves such a point obscure. Well, Helmholtz does so leave it. At one time he seems to fall back on inscrutable powers of the soul, and to range himself with the 'psychical stimulists.' He speaks of Kant as having made the essential step in the matter in distinguishing the content of experience from that form--space, course--which is given it by the peculiar faculties of the mind.[275] But elsewhere, again,[276] speaking of sensationalistic theories which would connect spatially determinate feelings _directly_ with certain neural events, he says it is better to assume only such simple psychic activities as we _know_ to exist, and gives the association of ideas as an instance of what he means. Later,[277] he reinforces this remark by confessing that he does not see how any neural process _can_ give rise without antecedent experience to a ready-made (_fertige_) perception of space. And, finally, in a single momentous sentence, he speaks of sensations of _touch_ as if they might be the original material of our space-percepts--which thus, from the optical point of view, 'may be assumed as _given_.'[278]