79.  From what has been said we may safely deduce this consequence; to wit, that a man born blind and made to see would, at first opening of his eyes, make a very different judgment of the magnitude of objects intromitted by them from what others do.  He would not consider the ideas of sight with reference to, or as having any connexion with, the ideas of touch:  his view of them being entirely terminated within themselves, he can no otherwise judge them great or small than as they contain a greater or lesser number of visible points.  Now, it being certain that any visible point can cover or exclude from view only one other visible point, it follows that whatever object intercepts the view of another hath an equal number of visible points with it; and consequently they shall both be thought by him to have the same magnitude.  Hence it is evident one in those circumstances would judge his thumb, with which he might hide a tower or hinder its being seen, equal to that tower, or his hand, the interposition whereof might conceal experimental means the firmament from his view, equal to the firmament:  how great an inequality soever there may in our apprehensions seem to be betwixt those two things, because of the customary and close connexion that has grown up in our minds between the objects of sight and touch; whereby the very different and distinct ideas of those two senses are so blended and confounded together as to be mistaken for one and the same thing; out of which prejudice we cannot easily extricate ourselves.

80.  For the better explaining the nature of vision, and setting the manner wherein we perceive magnitudes in a due light, I shall proceed to make some observations concerning matters relating thereto, whereof the want of reflexion, and duly separating between tangible and visible ideas, is apt to create in us mistaken and confused notions.  And first, I shall observe that the Minimum VISIBILE is exactly equal in all beings whatsoever that are endowed with the visive faculty.  No exquisite formation of the eye, no peculiar sharpness of sight, can make it less in one creature than in another; for it not being distinguishable into parts, nor in any wise a consisting of them, it must necessarily be the same to all.  For suppose it otherwise, and that the Minimum VISIBILE of a mite, for instance, be less than the Minimum VISIBILE of a man:  the latter therefore may by detraction of some part be made equal to the former:  it doth therefore consist of parts, which is inconsistent with the notion of a Minimum VISIBILE or point.

81.  It will perhaps be objected that the Minimum VISIBILE of a man doth really and in itself contain parts whereby it surpasses that of a mite, though they are not perceivable by the man.  To which I answer, the Minimum VISIBILE having (in like manner as all other the proper and immediate objects of sight) been shown not to have any existence without the mind of him who sees it, it follows there cannot be any pan of it that is not actually perceived, and therefore visible.  Now for any object to contain distinct visible parts, and at the same time to be a Minimum VISIBILE, is a manifest contradiction.