9. It seems then more reasonable in it self, as well as confiftent with the Principles of this Theory; to fay, that as Ideas are the immediate Objects of our Thoughts, and we underftand all things by them, fo all the diversity that is between the kinds of our Perception must be ftated upon, and derived from the diversity of those Ideas. And fince these Ideas tho' all of them effentially Spiritual, are yet as to their reprefentative Being, fome of them material, and fome of them immaterial, I would therefore affign this for the difference between imagination, and intellect strictly and properly fo call'd, that in the former, the immediate Object of Thought is an Idea that is reprefentatively material, and that in the lat ter the immediate Object of Thought is an Idea that is representatively immaterial. And therefore it is that it may with just propriety be call'd pure Intellect, as being a Perception purely Spiritual, or as we fay Intellectual, because without any corporeal Image. Not in the Senfe of the foremention'd Hypothefis, that is, that the immediate Object of it, is not Matter (for fo Imagination is pure too, as having for its Object an Idea effentially Spiritual) but that 'tis without any fuch Idea as reprefents Matter. And herein indeed confifts that purity of it, which diftinguishes it from that Counter-Perception which we call Imagination, whofe Object, tho' effentially Spiritual, as well as that of the other, is yet reprefentatively material.

SECT.

SECT. IX.

Thought and Vision compared with a fuller illuftra tion of the difference between Thought, in the way of Idea, and Thought in the way of Sentiment, with fome Philofophical Remarks upon the

r.

latter.

V

"Ifion is generally apprehended as a different thing from Thought (for we are not faid to fee whatever we think of) and yet at the fame time as fo resembling it, that Thought is oftentimes exprefs'd by Vision. As when we talk of our intellectual Sight or View, or fay that we plainly fee fuch a Thing to be true or falfe, &c. meaning that we clearly perceive it. And indeed Vifion does in fome refpects differ from Thought (or elfe whatever we think of, we should be faid also to see, and he that did not fee would also not Think, whereas none think fo ftrongly as the Blind) and yet in fome refpects again 'tis as true that Vifion is really Thought, and does not only resemble it. But now to adjust this rightly, and to fhew in what refpect Vifion differs from Thought, and in what refpect it is really the fame with it, is a pretty nice Point, in order to the clearing of which we had need confider Vifion as diftinctly as Anatomifts do the Eye.

2. Vifion then will admit of a twofold Confideration, and that fo utterly different one

from

from the other, as to have nothing in common but the Name. For firft, Vision may be confider'd materially and with refpect to the Body, as it fignifies the paffing or Trajection of the Rays of Light, with all their refractions thro' the several coats and humors of the Eye, and the Impreffion which they make in the bottom of it upon the Optick Nerve, or if you will that inner Tunicle or Membrane, composed by the little filaments or extremities of it, which Phyficians call the Retina. And in this Sense Vision is, or ought to be consider'd in that Branch of the Mathematicks which profeffes to treat of it, and is accordingly call'd Opticks. Which I think we ought not to define (as a certain * Philofo

pher does) as a Science of See

* Scheibler.

ing well. For Opticks do not teach us to fee, nor do we need any Science for that purpose, as being fufficiently inftructed by Nature. Nor yet perhaps (with * another)

appearance

* Keckerman in his Mathematical

Syftem.

as a Science of the of things which we perceive with our Eyes. For befides that the appearance of things and our Perception of them belongs properly to the Mind, and not to the Eyes. Our Perception of Things, or of their Appearances, is purely of a Phyfical Confideration, with which Opticks as being a Mathematical Science feems not to be concern'd, unless it be fo far as it may confider that which is the occafion of thofe appearan

ces.

ces. For indeed that I take to be the proper business of Opticks, namely to confider the Radiature of Light, and to fhew according to what lines it paffes through, and with what different Movements or Impreffions it affects the vifive Organs. So that when 'tis faid to treat of Vifion, it ought to be understood only according to this firft Sense of it.

3. But then there is another, and a nobler fense of Vision. For as it may be taken materially for that luminous Impreffion which affects the Eye or the Brain, fo it may also be confider'd formally, as it fignifies that inward Senfe or Perception which, according to the Law of Union establish'd by the Author of Nature between Soul and Body, follows upon, and is occafion'd by that Impreffion, and which we are confcious of to our felves whenever that Impreffion is duly made, and without which, notwithstanding any Impreffion of Light upon our Eyes we could not be faid properly (that is formally) to fee, any more than if we were altogether in the dark.

4. The Senfe of the Word Vifion being thus diftinguifh'd out of its ambiguity, we may now hope (what before would have been impoffible) to state the refpects of difference or of agreement which it has with Thought. For it is plain even at fight that Vifion, if you go no further than the firft Sense of it, is not Thought, but a mere mechanical Movement ar Impulfe, which tho' made upon a thinking

Crea

Creature, and that will alfo take occafion to think from it, has yet more of Thought in it, than if the fame Impreffion were made upon Water or upon a Looking-glafs. But then again if Vifion be taken in the fecond, and indeed more proper as well as eminent Senfe of it, then 'tis as plain that Vifion is Thought, and that 'tis not the Eye that thus fees, but the Mind. Vilion in this Senfe belongs as much to the Soul, as in the other to the Body, and is indeed as much a Thought of it, as any other Senfe or Perception that it has.

5. But do we fee then whatever we think of? That indeed would be happy for those who lament their abfent or dead Friends, and live almoft upon the dear Remembrance of them, if by Thinking upon them, they could as it were conjure up their appearance, and fet them before their view. Or again on the other fide when we fhut our Eyes, or otherwise do not fee, do we then alfo ceafe to Think? That would be full as miferable for thofe that are Blind, if with the lofs of their Sight, they must lose the ufe of their Understanding too. And yet thus it must be, if Vision and Thought be really and abfolutely the fame thing.

6. To difintricate our felves then from this seeming intanglement, I further confider, that tho' Vifion according to the formal Senfe of it, be really Thought, as much as any that paffes in our Minds, yet even thus confider'd it is a peculiar Thought, as having fomething in the

man