1 Design

2 Distance of itself invisible

3 Remote distance perceived rather by experience than by sense

4 Near distance thought to be perceived by the angle of the ‘optic axes’

5 Difference between this and the former manner of perceiving distance

6 Also by diverging rays

7 This depends not on experience

8 These the common accounts, but not satisfactory

9 Some ideas perceived by mediation of others

10 No idea which is not itself perceived can be the means of perceiving another

11 Distance perceived by means of some other idea

12 Those lines and angles mentioned in optics are not themselves perceived

13 Hence the mind does not perceive distance by lines and angles

14 Also because they have no real existence

15 And because they are insufficient to explain the phenomena

16 The ideas that suggest distance are 1st the sensation arising from the turn of the eyes

17 Betwixt which and distance there is no necessary connexion

18 Scarce room for mistake in this matter

19 No regard had to the angle of the optic axes

20 Judgment of distance made with both eyes, the result of experience

21 2ndly. Confusedness of appearance

22 This the occasion of those judgments attributed to diverging rays.

23 Objection answered

24 What deceives the writers of optics in this matter

25 The cause, why one idea may suggest another

26 This applied to confusion and distance

27 3rdly. The straining of the eye

28 The occasions which suggest distance have in their own nature no relation to it

29 A difficult case proposed by Dr. Barrow as repugnant to all the known theories

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