Observations on the nature and theory of vision : with an inquiry into the cause of the single appearance of objects seen by both eyes / by John Crisp, F.R.S.
- Crisp, John
- Date:
- MDCCXCVI [1796]
Licence: Public Domain Mark
Credit: Observations on the nature and theory of vision : with an inquiry into the cause of the single appearance of objects seen by both eyes / by John Crisp, F.R.S. Source: Wellcome Collection.
Provider: This material has been provided by the Francis A. Countway Library of Medicine, through the Medical Heritage Library. The original may be consulted at the Francis A. Countway Library of Medicine, Harvard Medical School.
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![[ io8 ] appearing in the fame diredion; and even if we fliould take up the matter in the latter form, there would ftill arife this queftion. Why do the two optic axes ap- pear united throughout their whole length ? which is only another mode of ftating the queftion, Why do objecfls appear fingle as feen by both eyes ? But if we Ihould con- sider the two circumftanccs, united appear * ance and feeming diredfion, as being one de- rived from the other, I conceive it to be moft conliftent with the rules of found phi- lofopliy, to confider the latter as the confe- quence of the former, the firft being an ac- tual matter of fight and the other an acquired motion, which is properly to be referred to fome faculty diftincS from fimple vifion; and I apprehend that every propofed folu- tion of this celebrated queftion, which de- rives the fingle appearance from circum- ftanccs which imply externality and remote- nefs in the objects of fight, muft be erro- neous and unfounded.](https://iiif.wellcomecollection.org/image/b21175408_0130.jp2/full/800%2C/0/default.jpg)
