“Heinc dici posse videtur: solem humilem oculo spectatum ideo apparere majorem, quam dum altius egreditur, quia dum vicinus est horizonti prolixa est series vaporum, atque adeo corpusculorum quæ solis radios ita retundunt, ut oculus minus conniveat, et pupilla quasi umbrefacta longe magis amplificetur, quam dum sole multum elato rari vapores intercipiuntur, solque ipse ita splendescit, ut pupilla in ipsum spectans contractissima efficiatur. Nempe ex hoc esse videtur, cur visibilis species ex sole procedens, et per pupillam amplificatam intromissa in retinam, ampliorem in illa sedem occupet, majoremque proinde creet solis apparentiam, quam dum per contractam pupillam eodem intromissa contendit.” Vid. _Epist. 1. De Apparente Magnitudine Solis Humilis et Sublimis_, p. 6. This solution of Gassendus proceeds on a false principle, to wit, that the pupil’s being enlarged augments the species or image on the fund of the eye. ‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐ _Thirdly_, against what is said in Sect. 80, it is objected, that the same thing which is so small as scarce to be discerned by a man, may appear like a mountain to some small insect; from which it follows that the _minimum visibile_ is not equal in respect of all creatures(462). I answer, if this objection be sounded to the bottom, it will be found to mean no more than that the same particle of matter which is marked to a man by one _minimum visibile_, exhibits to an insect a great number of _minima visibilia_. But this does not prove that one _minimum visibile_ of the insect is not equal to one _minimum visibile_ of the man. The not distinguishing between the mediate and immediate objects of sight is, I suspect, a cause of misapprehension in this matter. Some other misinterpretations and difficulties have been made, but, in the points they refer to, I have endeavoured to be so very plain that I know not how to express myself more clearly. All I shall add is, that if they who are pleased to criticise on my _Essay_ would but read the whole over with some attention, they might be the better able to comprehend my meaning, and consequently to judge of my mistakes. ‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐ I am informed that, soon after the first edition of this treatise, a man somewhere near London was made to see, who had been born blind, and continued so for about twenty years(463). Such a one may be supposed a proper judge to decide how far some tenets laid down in several places of the foregoing Essay are agreeable to truth; and if any curious person hath the opportunity of making proper interrogatories to him thereon, I should gladly see my notions either amended or confirmed by experience(464). A TREATISE CONCERNING THE PRINCIPLES OF HUMAN KNOWLEDGE [(465)PART I] WHEREIN THE CHIEF CAUSES OF ERROR AND DIFFICULTY IN THE SCIENCES, WITH THE GROUNDS OF SCEPTICISM, ATHEISM, AND IRRELIGION, ARE INQUIRED INTO _First Published in 1710_