Philos. [f. THAT dem. pron. + -NESS.] The quality or condition of being ‘that,’ i.e., of existing as a definite thing.
1643. Digby, Observ. Relig. Med. (1644), 86. It is evident that samenesse, thisnesse, and thatnesse, belongeth not to matter by it selfe,… but onely as it is distinguished and individuated by the forme.
1889. Mivart, Truth, 211. It apprehends what kind of a thing the object perceived may be—its ‘thatness,’ so to speak.
1891. E. B. Bax, Outlooks fr. New Standpoint, III. 183. The phenomenon or sign of the being or of the thatness which itself ever eludes us. Ibid., 191. Imparting to whatness a thatness.
1904. Athenæum, 24 Dec., 868/2. The investing of the content, which is in Bradleian language a ‘what,’ with self-existent reality or ‘that-ness.’
