[f. L. extens-us (see EXTENSE) + -ITY.] The quality of having (a certain) extension; in Psychol. of the breadth of sensation, as opposed to intensity (see quot. 1886).
a. 1834. Coleridge, in Blackw. Mag. (1882), CXXXI. 125/2. Intensity and extensity combinable only by blessed spirits.
1874. Carpenter, Ment. Phys., I. i. § 25. Its intensity is in a precisely inverse ratio to its extensity.
1886. J. Ward, in Encycl. Brit., XX. 46. In our organic sensations, we can distinguish … variations of quality, of intensity, and of what Dr. Bain has called massiveness, or, as we will say, extensity. This last characteristic … is … an essential element in our perception of space.
