Tag Archives: Touch

Berkeley’s Direct Tactile Realism In His NEW VISION

Oddly enough for those of us used to thinking of Berkeley as a thoroughgoing idealist, Berkeley maintains in his AN ESSAY TOWARDS A NEW THEORY OF VISION a direct realism regarding tactile perception.  Whereas the objects of vision — for example, the visible moon — do not exist outside the mind, the objects of touch — what is touched, tangible objects — do exist outside the mind in external space.  As George Pitcher puts it, speaking of what Berkeley is claiming in black and white in the NEW THEORY OF VISION:

What we feel are the tangible objects — i.e., the objects that are spread around us at various points in physical space.  What we see are objects that exist only in the mind.

George Pitcher, BERKELEY: THE ARGUMENTS OF THE PHILOSOPHERS  (Routledge, London and New York), p. 28. Henceforth BERKELEY

Tangible objects, in the system of the Essay, exist around us in real physical space.

George Pitcher, BERKELEY, p. 43.

And from the Master himself:

For all visible things are equally in the Mind, and take up no part of the external Space.  And consequently are equidistant [in the next sentence Berkeley says ‘Or rather to speak truly…are at no Distance, neither near nor far…] from any tangible thing, which exists without the Mind.

George Berkeley, AN ESSAY TOWARDS A NEW THEORY OF VISION, paragraphs CXI and CXII, in The GEORGE BERKELEY COLLECTION: 5 CLASSIC WORKS, Amazon Print-On-Demand Edition, no pagination.  Henceforth A NEW THEORY OF VISION. 


Perceiving for Berkeley (I will venture now…though I may end up chipping away at this claim) is always a two-place relation between a Mind that perceives something and the thing that is perceived.  In the case of vision, this relation is for Berkeley a two-place relation between the Mind and an entity that exists only in the mind, a visual Idea.  In the case of touch, this relation is a two-place relation between the Mind and a hard or soft or rough or smooth or sharp or rounded…object existing in external space (or at least this is what Berkeley cares to state explicitly in black and white in his NEW THEORY OF VISION.)

In the case of vision, I perceive extra-mental object existing in external space only indirectly, or mediately, in a three-place relation between my Mind (me), the Visibile Idea (e.g., the Visibile Moon) to which my Mind is related directly, and the external object (the physical, tangible Moon) for which the Visibile Moon serves as a sign.  So with regard to vision, Berkeley maintains (at least in what he sets down in black and white on the page) a representational theory of perception.  He is an indirect realist with regard to vision:  we see the physical object in external space just indirectly, in a way mediated by the mental object of color and shape that we do see directly.

But with regard to touch, Berkeley is a direct realist.  We perceive the physical object directly through touch.  We don’t perceive it by ‘touching’ or ‘feeling’ a mental object that represents the physical tangible object.  We are in contact with the object itself.  Put another way, our perception reaches all the way to the felt object.  In the case of touch, the perception is a two-place, not a three-place relation.

This direct realism in the case of touch comes as a bit of a surprise to those of us who think of Berkeley as a thoroughgoing idealist who thinks that everything is mental.  And in fact Berkeley apparently claimed in later writings that he theorized touch this way only to prevent his readers from freaking out from far too much counterintuitive idealism (Pitcher, BERKELEY, p. 28) which would only have served to distract his readers from what he wanted to focus on, namely, vision. In his own thoughts, ostensibly kept to himself at the time of A NEW THEORY OF VISION, he regarded the objects of touch as in fact mental.  But regardless of what the historical George Berkeley thought or did not think inwardly as he wrote that tract, treating touch in a direct realist fashion as involving direct perceptual contact with the touched/felt physical object is strongly motivated by how he conceptualizes the (ostensibly just mental) objects of vision.

As I have discussed in a previous post, The Truth Of Bishop Berkeley (Part 0),  Berkeley treats the visible object has properties.  The Visibile Moon, for example, is round, flat, luminous, and of a certain pale cheese-like yellow. If we think of the objects of touch as having analogous properties, those properties would be rough, smooth, hard, soft, and so on.  But surely no mental things can be rough etc.  Only physical objects — for example, the bark of a tree, the cool smoothness of marble — can have these properties.  Thus conceptualizing Ideas as having properties puts Berkeley straightway on the road to regarding physical objects existing in extra-mental space as the objects of touch.

Touch lends itself to a direct realist interpretation in a way that vision does not.  The seen object at least seems to be at a distance from the sensing surface of the see-er.  How can the visual experience include anything at a distance from this sensing surface?  It would seem prima facie that anything away from that surface would have to be outside the experience. The visual experience would therefore be confronted with the impossible-to-fulfill need to “reach out” to the seen object.  This, at least, is how I try to articulate the intuition that vision poses a problem for a direct realist interpretation of the seen object.

By contrast, there is zero distance between the sensing surface of my skin and the rough bark of the tree as I run my hand along the bark’s surface. Through touch, I am in contact with the physical object itself.  There is no question of the tactile experience having to “reach out” to the object because a physical me, engaging my physical hand, has already done the reaching out.  Touch is the direct realist sense par excellence.

And, as I hope to show (soon, or at least sometime before I die), the visual experience actually does reach out (in some sense of ‘actually does reach out’) to the physical object (Merleau-Ponty), or at least seems to so reach out (Berkeley) because of the way touch is implicated in the visual experience.  Touch informs the direct realist character (real or ostensible) of visual experience.




This time my homage to Plato’s SYMPOSIUM takes the form of Brad Pitt in THE FIGHT CLUB.  This image seems appropriate for a disquisition on touch and brutal physical reality.


If Plato can have a thing for Alkibiades, I can have a thing for gorgeous rednecks.  This particular redneck needs to stop smoking, however.























The Truth Of Bishop Berkeley (Part 0)

Essay:  Noun:`
  1. a short literary composition on a particular theme or subject, usually in prose and generally analytic, speculative, or interpretative.
  2. an effort to perform or accomplish something; attempt.
  3. a tentative effort; trial; assay.
Essay:  Verb (used with object)

  1. to try; attempt.
  2. to put to the test; make trial of.


This Essay:  Transforming George Berkeley Into Maurice Merleau-Ponty

There is a not-completely inchoate notion lingering in my head that if we tweak this or that position held by that Irish Anglican Bishop George Berkeley ( 1685 – 1753 — about the same time Johann Sebastian Bach lived) — especially his positions regarding visual depth and the relation between vision, touch, and the motions of the body — we will end up with something like Merleau-Ponty ( (1908 – 1961).  The effect may be a bit like those step-by-step transformations of a picture of one celebrity into a picture of another celebrity.

I propose then a series of posts, starting with this one, which will be an essay — a trial, an attempt — to try to do just this.  (Change George Berkeley’s nose just a little bit, then lengthen the chin a notch, then….)  I will be putting my currently somewhat inchoate notion to the test, making a trial of it, to see if I can come up with genuine insight into Merleau-Ponty, or better, into the phenomena he was concerned with.

Clearly, Merleau-Ponty advances positions that directly contradict Berkeley’s.  But along with this opposition that makes Berkeley an excellent foil to Merleau-Ponty, there is, I think, a surprising degree to which Berkeley is on the same wavelength as Merleau-Ponty, with the consequence that Berkeley can illuminate Merleau-Ponty in a way other than just being a foil to him.1 Just as Merleau-Ponty recognizes a ‘truth of solipsism’, I think a Merleau-Pontyian might recognize a ‘truth of Berkeley’ — or at least a truth regarding Berkeley’s claims regarding depth which will illuminate our perceptual opening onto a world that is at once our “flesh” and not us.  In this opening, I claim, the perceived object is both immanent and transcendent . . . and this is my essay towards making sense of this.  Will I succeed?

Apart from illuminating some of the phenomena described and explicated by Merleau-Ponty, one of my sub-aims is to work through (in subsequent posts — not this one) the arguments of an article I published in a previous life (Cliff Engle Wirt, THE CONCEPT OF THE ECSTASIS,2 Journal of the British Society for Phenomenology, 14, 79–90, January 1983) in such a way as to make those more arguments more intuitive, or at least less absolutely repellent, to a certain person of my acquaintance . . . a person who is, I think, a bit too uncritically enamoured of a certain British Empiricist.  (No, not George Berkeley, but John Locke.  But never mind.)  This person would sometimes say things to the effect of “If what you were saying applied only to what’s inside the mind, I would consider it.”  So I want to see how far I can go in sticking to the framework of ‘just what is immanent to the mind.’  Then later, I will see what, if anything, I can make ‘transcendent’ of the mind — or, more precisely, of the body in its subjectivity.

The essay comprising all these posts may not be exactly short, but perhaps we can re-interpret ‘a short literary composition’ in the definition of ‘essay’ shown above to mean something like ‘less lengthy than Tolstoy’s WAR AND PEACE’.  In what follows, I will retain Berkeley’s not-quite-modern capitalization and spelling practices in my own text when the concept is Berkeley’s, or at least taken by me to be Berkeleyian.  (I won’t be attempting, however, to be absolutely precise or consistent in this endeavor.)


George Berkeley On The Visibility (Invisibility) Of Depth

Let me make a start in this (possibly dubious) endeavor by jumping into Berkeley’s assertions regarding the visibility (invisibility) of depth in his AN ESSAY TOWARDS A NEW THEORY OF VISION.  Berkeley’s claims regarding depth nicely motivate my claims about the ekstasis and the claims I make about the ekstasis would be less likely to freak out a dualist when made inside a Berkeleyian context.   Berkeley’s claims about the invisibility of depth are true in the real, non-Berkeleyian world only in special cases; nonetheless, this will still be enough to motivate my claims about the ekstasis.

Berkeley plunges into an argument that depth is invisible in the second paragraph of his AN ESSAY TOWARDS A NEW THEORY OF VISION. 

II.  It is, I think, agreed by all, that Distance [of an object in depth], of it self and immediately, cannot be seen.  For Distance being a Line directed end-wise to the Eye, it projects only one Point in the Fund of the Eye, which Point remains invariably the same, whether the Distance be longer or shorter.

George Berkeley, AN ESSAY TOWARDS A NEW THEORY OF VISION, paragraph II, in The GEORGE BERKELEY COLLECTION: 5 CLASSIC WORKS, Amazon Print-On-Demand Edition, no pagination.  Henceforth A NEW THEORY OF VISION. 


This passage produced in me a sudden Aha Erlebnis ages ago, when I first encountered it in a little cottony-red cloth-bound book my parents had bought in their college days in the 1940s.  I experienced a flash of intuition to the effect that no, depth cannot be seen.  The passage still produces this Aha Erlebnis in me even now, even though that Erlebnis very much resists getting cashed out analytically.  Something seems right about it.

Naturally, the passage is ambiguous and what, exactly, the argument is, is not completely clear.  Is Berkeley talking about Lines and Points in Euclidean geometry?  Is he talking (as he probably is) about Lines as rays of light bouncing off an Object and striking a spot or Point on the retina?  Is he talking about Visible Lines that can be Blue, Red, Green, Orange, Purple, Violet, or Burnt Sienna?  I will be going into a little bit more detail below about these three different interpretations of what ‘Line’ means in Berkeley’s paragraph II.

But for now I will just note that I follow George Pitcher, who surmises in his BERKELEY:  THE ARGUMENTS OF THE PHILOSOPHERS that Berkeley is talking about rays of light and the retina.  If so, Berkeley’s argument fails for essentially the reasons that Pitcher points out in Chapter II of his book (though naturally I don’t agree with everything Pitcher says).  Nor does any one of the other explicitly-stated arguments made by Berkeley that I have encountered so far work.

Nonetheless, I think it is possible to argue for Berkeley’s assertion that depth cannot be seen by relying on the Berkeleyian concept of a ‘Minimum Visibile’ and some other notions Berkeley holds about Ideas of Vision.  If these concepts are valid, Berkeley’s claim about depth does hold, regardless of the validity of his argument quoted above.  In future posts I will then use the Berkeleyian-world arguments and the real-world arguments to motivate the claims I make about the ekstasis.

As it happens, I don’t think Berkeley’s concepts are valid.  (Please — I am not completely nuts.)  Nonetheless, I will ignore this disagreement long enough to accomplish the task noted above, namely, making certain arguments that may seem to the dualist utterly wild outside the realm of Berkeleyian Minds filled with their Ideas.


Berkeley’s Visual Ideas:  A Minimalist Presentation

The subheading of course is a pun:  I am launching into a minimal presentation of Berkeley’s theory of Visual Ideas, and the basic unit of Berkeley’s Visual Ideas is itself a minimal presentation.

Infinitely Thin Slices Of Yellow Cheese:  Berkeley’s Visual Ideas are what we see.  They are the objects of sight.  For example, I see the moon.  The moon is the object of my vision. It is a Visual Idea.  Let’s call it the Visible Moon.

Visual Ideas have properties. For example, the visible Moon is “…a small, round, luminous Flat…” (Paragraph XLIV).  I do not doubt in the slightest that Berkeley would add ‘of a whitish or a beautiful pale yellow color not totally unlike certain cheeses” to the list of properties possessed by the visible Moon.

Although I may find myself contradicted as I read further in A NEW THEORY OF VISION and other works by Berkeley, I will go out on a limb and assert that for Berkeley, a Visibile Idea (or an Idea of any kind) can have only those properties that appear to one (get presented to one) in their Mind.  If an Idea has a property, that property gets presented to the Mind. In other words, I am wagering that for Berkeley there is nothing hidden in an Idea.  For how can something be before the Mind at the same time it is hidden from the Mind?  We are talking about Ideas, after all, which should be purely Intelligible.  There should be nothing hidden or obscure about them.

As a corollary to this, I will also wager that for Berkeley, if the Mind cannot tell two Ideas apart based on their properties, the Mind in fact has one, not two Ideas before it.  Nothing being hidden from the Mind in an Idea, the (putatively) distinct Ideas cannot differ by virtue of some property hidden from the Mind (such as the location of one Idea “behind” the other.  See below) .

The Ideas of Sight are individuated by their properties since the Mind tells them apart by their properties.  So what I call the ‘visible Moon’ is, actually, a set of different Visible Ideas going under the same verbal heading, ‘visible Moon’.  For were I to get right up close to the moon, what I see would be different, since it has different properties.  It would be, for example, much larger, taking up most or all of my visual field.  Doubtlessly its color would be different.  So what I see would be different.  It would be a different Object of Vision, a different Idea of Sight.  For if two things have different properties, they cannot be the identical Object, right?

The visible Moon (I mean the one I see now, as I am standing on the earth) does not exist outside my Mind.  It is immanent in my Mind.  For the visible Moon has a color, and colors exist only in the mind.  We cannot separate out even in thought Extension (for example, the width and height of the visible Moon) and Color:

Is not the Extension we see coloured, and is it possible for us, so much as in Thought, to separate and abstract Colour from Extension?



So if the visible Moon’s pale yellowish color is in my Mind, so are its width and height.  The visible Moon therefore exists only inside my mind, and not outside of it.  (Don’t worry, I am not hogging the sole visible Moon to myself.  You have another visible Moon in your mind.  This is just another case of a set of different Objects going under the same verbal heading, ‘visible Moon’.)

The ’round, luminous Plain’ that is the visible Moon, Berkeley says, is “of about thirty visible Points in Diameter” (A NEW THEORY OF VISION, paragraph XLIV).  A visible Point is the Minimum Visibile, i.e., that Object of Sight that is of a size just large enough to be seen.  Berkeley takes it to be self-evident that the Minimum Visibile cannot have parts:

…the Minimum Visibile having . . . been shewn not to have any Existence without the Mind of him who sees it, it follows there cannot be any Part of it that is not actually perceived, and therefore visible.  Now for any Object to contain several distinct visible Parts, and at the same time to be a Minimum Visibile, is a a manifest Contradiction.



Being simple, without parts, the Minimum Visibile cannot have structure.  It is merely a (barely) visible Point, with a kind of size (but with this notion of size some issues start to intrude which I will simply ignore for the moment — for at least as long as I am not absolutely forced to consider them), to be sure, but very little of that.


Arguments Using Berkeleyian Concepts

Enough of Berkeley’s Ideas of Vision for the moment, except for two last notes.  First note: above, I have been using ‘visual Idea, Visible Idea, Idea of Sight, Object of Vision, and Object of Sight interchangeably.  I will be continuing to do so.

Second note:  although Berkeley thinks of Ideas of Sight as themselves having colors, I myself share Daniel C. Dennett’s opinion that “…there are no sense-qualia, that is, no ‘inner figment[s] that could be colored in some special, subjective … sense.'”  (Dennett as quoted in Lawrence Hass, MERLEAU-PONTY’S PHILOSOPHY, Indiana University Press, 2008.)  And one wonderful milepost in my philosophical journey was James W. Cornman’s MATERIALISM AND SENSATIONS (Yale University Press, 1971), in which he uses the adverbial theory of perception to get rid of, for example, the blue of a blue afterimage, this blue standing in the way of his desire to identify the afterimage with a brain event.  But for now, I will be pretending that there are such critters as Berkeley’s Ideas of Sight that themselves have colors and (two-dimensional) shapes.

[Also discuss the fact that the notion of ‘size’ is a bit problematic if we don’t have a unit of measure for it — centimeters, inches, whatever.]

Depth Considered As A Line Ala Berkeley:  My arguments using Berkeleyian notions will start with how Berkeley explicitly conceives of depth in paragraph II of his A New THEORY OF VISION, i.e., as Distance considered as a Line extending from the Object seen to the retina one one’s eye.  (Until further notice, I will consider just one eye, as if we were Cyclopean creatures.)  Then I will turn to a conception of depth as a kind of funnel extending from the eye to the Object.

As I suggested above, there are several possible candidates — four, in fact, that I have uncovered so far — for what Line might be regarded as identical with depth considered as Distance.  It is not totally impossible, I suspect, that Berkeley is mushing all four candidates together.

Let me note at the start that the idea that a Line becomes invisible when it is completely end-wise to the eye suggests that it is visible when it is not completely end-wise to the eye — for example, when it extends horizontally in front of you.  Otherwise, what would be the point of showing that one special type of Line — the type comprising those Lines directed end-wise to the Fund of the Eye (i.e., the retina) — is invisible?  Why single out depth as if it were a special case?  Why not launch into a discussion of the claim that both breadth and depth are invisible?

First, the line could be a line in Euclidean geometry.  But these lines are invisible because they have no width or thickness, and Berkeley seems to be implicitly contrasting lines extended in breadth, which can be seen, and the non-visible line that is identical with breadth.  Breadth, i.e., a line in breadth, can be seen, he seems to imply, but depth, i.e., a line in depth, cannot.  If all Lines were invisible, there would seem to be little point in claiming that a Line visible to me because it lies horizontally before me would become invisible to you because it is directed end-wise to your eye.

Second, the line could be a light ray.  This is the interpretation that George Pitcher favors in his BERKELEY:  THE ARGUMENTS OF THE PHILOSOPHERS.  Berkeley’s topic is optics, after all, and apart from that, a light ray is what one would normally think of when talking about lines extending from the object and projecting a point onto the retina.  But I do have to wonder a bit if this is 100% of Berkeley’s meaning — for are not individual light rays traveling horizontally in front of you also invisible?  And isn’t Berkeley implying that lines in breadth are visible?  At any rate, Pitcher shows rather definitively that Berkeley’s argument will not work if the Line is considered to be a light ray.

Third, the line could be a Visible Line (and the Point he mentions in the passage above a Visible Point), such as the Blue Line and a Red Line that Berkeley says he can conceive as having been added together to form a larger line (A NEW THEORY OF VISION, paragraph CXXXI).  In addition to Berkeley’s Blue and Red Lines, I am about to introduce into the picture a Green Line.  But Line considered as a Visible Line does not fit with perfect cleanness into Berkeley’s passage above either, since it is hard to give a sense to the notion that such a Line could project a Point onto the retina, that is, extend from the Object into the eye and onto the Fund of the Eye.  Would not such a Line become invisible at some point beyond the cornea?

No, I do not intend to conduct a Buñuelesque experiment with a thin visible plus tangible wire — certainly not on my eye! — to determine at exactly which point the wire ceases to be visible and remains merely tangible as it penetrates the eye.  But bringing the wire into the picture introduces yet another candidate for Berkeley’s Line — this is the fourth possibility — i.e., a Tangible, as opposed to Visible Line.  The person already acquainted with Berkeley (perhaps more than I am at the time of this writing) will note that Berkeley makes a sharp distinction between the two — a Visible Line may be closely associated with, but is never identical with, a Tangible Line.  Visible Lines and Tangible Lines are always two different critters.  But this Tangible Line would always be invisible, even in breadth, so running afoul of what I take to be Berkeley’s implicit contrast between Lines in depth which are invisible vs Lines in breadth which are visible.

In Berkeley’s terms at least part of the Visible Line would suffer from a ‘failure to exist’ at some point past the cornea.  Yet Berkeley seems to imply that there is such a Line projecting a Point from the Object to the Fund of the Eye.  Therefore this Line cannot be a Visible Line.  So a Visible Line cannot be a candidate for what ‘Line’ means in Berkeley’s Paragraph II.

This of course already establishes part of Berkeley’s argument that depth considered as a Line is invisible, since the Visible Line cannot even be a candidate for the Line projecting a Point onto the retina that Berkeley says is depth.  But since it is still possible that such a Visible Line would be visible at, e.g. some point in front of the retina, it would not suffice to establish all that I suspect Berkeley thinks he has established regarding the invisibility of depth, that is, that depth is invisible tout court.  I will try to establish below some further considerations that, I claim, do establish this, given certain Berkeleyian notions.

To sum up:  while Line as light ray is doubtlessly the interpretation that fits Berkeley’s passage the best, the fact that not one of the four interpretations fits that passage with total cleanness heightens my aforementioned suspicion that all four may be at play — doubtlessly unconsciously — in Berkeley’s mind as he writes the passage.3  At any rate, I assert that an argument for Berkeley’s claim that depth is invisible can  be constructed based on Visible Lines, Minimum Visibles, and at least one conception of Berkeleyian Ideas (the one offered above).  This argument, I assert, does work — provided one grants Berkeleyian Minimal Visibles and the other items in the apparatus of (what I take to be) his Theory of Ideas.

Let me proceed then by introducing into the picture a Green Line  — in fact, not just a Green Line, but a bright chemical polyester Green Line.

Suppose I see a length of bright chemical polyester green bungee cord that my friend is now holding in front of me. In Berkeleyian terms, to see a length of the bungee cord is to see a succession of visible Points, an array of bright green Minimum Visibiles, one next to the other.  Nothing problematic about that.  (But notice that I suddenly shifted from ‘bright chemical polyester green’ to just ‘bright green’!  I hope to argue in a later post that ‘bright chemical polyester green’ as opposed to just ‘bright green’ requires a structure that the Minimum Visibile does not have.)  The Visual Idea of Length would then be a composite Idea comprising an array of Minimum Visibles.  This composite Visual Idea would have the property Length, and this property would appear to one, be visually presented to one, in their Mind.

By analogy, then, to see depth — to have an Idea of Sight of the Line extending endwise to the Eye, would be to see an array of Minimum Visibiles one behind the other.  This would have to be a composite Visual Idea which has the property depth, which property appears to one, gets presented to one in their Mind.  But of course the Minimum Visibles comprised by this Idea cannot have the property bright green!  Nor can these Minimum Visibiles have any other color … or at least any opaque color.   To see why, consider (per impossible) any given such Minimum Visibile.  That Minimum Visibile would be hiding the Minimum Visibile behind it.

Well, let’s consider a Minimum Visibile that is not opaque, but translucent or even transparent.  Consider the transparent Minimum Visibile first.  It cannot be completely transparent, for then it would be an invisible Object of Sight, a seen Object that is not seen.  This would obviously be a contradiction.  The Minimum Visibile would than have to have some property that would let us say that we see enough of it for it to indicate a plane in space — the plane ‘directly’ (more on this shortly) in front of the Minimum Visibile behind it.  Say, there is some sort of highlight of the sort that one might see on a (mainly) transparent sheet of cellophane or acrylic that indicates there is something occupying a particular spatial plane.  For the Visibile Minimum to have anything like this, it would have to have parts — a structure.  One part would have to be the highlight, and another part could have to be translucent somehow….not invisible.  (I will get to this translucency business in a moment.)  But we have seen that Berkeley’s Minimum Visibile cannot have parts.

Well then, let’s consider, not an (impossible) Minimum Visibile with a cellophane-like highlight, but a simply translucent one with no variation in color or light.  Let’s say it is a nice translucent light blue.  Behind it (per impossible I am sure) there is a minimal Visible of a darker blue luminously showing forth through the first Minimum Visibile.  But how would the color of the first, foremost light blue Minimum Visibile show itself to the Mind?  It must, given my postulation above that every property of a Berkeleyian Idea must present itself to the Mind, that in a Berkeleyian Idea nothing is hidden.  But as a Minimum Visibile, our light-blue Idea has no parts, such that one part could show the darker blue of the Object behind it, while another part would show its own light-blue color.  What gets presented is just the dark-blue color.  Because an Idea must present a property to the Mind if it is to have that property, the light blue idea I have postulated cannot exist.

Okay then, lets postulate a translucent “first and foremost” Idea that is the same hue of dark blue as the Idea it covers.  But since there is just one color-and-light property of luminous blue at this minimally visible point, the ‘first and foremost’ Idea cannot be distinguished by the Mind from the Idea behind it.  Moreover, the two Ideas have the same size (both being minimally visible) and the same shape (presumably round, since they are Points.)  This, I do believe, pretty much exhausts the arsenal of properties of Berkeleyian Visual Ideas that would serve to distinguish one from the other in the Mind.  The (putatively) two ideas differ in their locations, of course, but there does not seem to be any purely visual property that would enable the Mind to distinguish the two locations (one Idea with this color, luminosity, and shape on this plane; the other Idea with this other color, luminosity, or shape on the plane behind it) and get a handle on the different positions of the Ideas.  If the Berkeleyian Mind cannot distinguish (putatively) two different Ideas, those (putatively) distinct ideas are in fact one.  So in this case there is just one Idea of blue getting presented to my Mind.

So because there would have to be two Ideas were one Idea to show through behind another Idea, one Idea cannot show through another.  All Berkeleyian Ideas are opaque.  Any impression to the contrary, any apparent translucency, would have to be explained by something other than an Idea of Sight entering the picture (so to speak).  (Any takers for Ideas of Feeling and Kinaesthesia?)

Therefore, if one allows Berkeley’s notion of the Minimum Visibile, depth considered as a Line extending endwise to the Eye cannot be seen.  There is no such Object of Sight, no such visible Idea.  There cannot be a succession of Minimum Visibiles, one arrayed behind the other.  There can be only a single Point presented to one in their Mind.

This aligns nicely with the passage quoted above from A NEW THEORY OF VISION, in which Berkeley says:  “For Distance being a Line directed end-wise to the Eye, it projects only one Point in the Fund of the Eye, which Point remains invariably the same, whether the Distance be longer or shorter.”  Take the bright polyester chemical green bungee cord so that it extends end-wise towards the eye, mentally reduce that end to a single Minimum Visibile, and — voila!  One sees just that one Point, which will remain the same (abstracting away all perturbations of that Point) regardless of whether the Line behind it becomes shorter or longer accordingly as the bungee cord is stretched or allowed to relax.




Depth Considered As A Funnel:  Can we rescue the notion that there exist visual Ideas of depth if we no longer insist that depth be conceived of as a Line?  What if we thought of depth as a kind of funnel extending from the eye to the Object?  Any given Visual Idea that is in front of another one could then have the structure necessary for it to appear in front of the Visual Idea behind it, since, no longer being a Minimum Visibile, it can now have parts.  (Perhaps the behind-most Visible Idea could be a Minimum Visibile without parts.)

But this attempt to prevent the notion of a Visual Idea of depth from biting the dust fails once one asks themselves whether Visible Ideas can have a Minimum Thickness as well as a Minimum Diameter.  Since such a thickness could never appear (can one turn a Visible Idea around so as to see its side?), and since an Idea cannot have (I am assuming so far) any property that does not appear to one in their Mind, it would seem that the Minimum Visibile could not have a thickness.  (The Visible Moon in that regard would be like an infinitely thin slice of yellow cheese.)   In that case, it would, like a plane in geometry, have only two dimensions — height and width.  In spite of Berkeley’s hesitation (at least I am getting hints at such a hesitation as I go through A NEW THEORY OF VISION) to treat Ideas as objects in a Euclidean Geometry, I think he would be forced to do so at least in regard to the distance between a Visual Idea and any Visual Idea behind it.  Between any two such Visual Ideas there would have to be an infinite number of planes, since between any two points on a Euclidean line there are an infinite number of other points.  There would, then, have to be an infinity of Minimum Visibiles (differentiated somehow, say, by color?) stretching from the Object (say, the bright polyester chemical green bungee cord your friend is holding) you see to your Eye.  This would be so no matter how shallow the depth is.

But such a Line would be a Visible Line, i.e, a sensible Extension by hypothesis.  And Berkeley is sure that sensible Extension is not infinitely divisible:

For, whatever may be said of Extension in Abstract, it is certain sensible Extension is not infinitely Divisible.  There is a Minimum Tangibile, and a Minimum Visibile, beyond which Sense cannot perceive.  This every ones Experience will inform him.



Therefore, it would seem, Berkeley would have to reject that notion that there can be a succession or array of (non-minimal, i.e., composite) Visible Ideas lying one behind the other in a kind of funnel.

But maybe it could be objected that Berkeley’s argument that a sensible Extension cannot be infinitely divisible because it is a composition of Minimal Visibiles applies only to visible Lines in breadth, and only to finite minds.  The fact that (in Berkeley’s world) a Minimal Visibile would disappear should its breadth decrease prevents a sensible Line in breadth from becoming divided infinitely.  But no such consideration would hinder an infinite number of composite Ideas lying one behind the other for any intelligence that could perceive an infinite number of Ideas at the same time.   (For now I will leave the ‘at the same time’ part as an exercise for my ((probably)) non-existent reader; I really should get back to this at some point, though.)

It would seem that by the time he writes A TREATISE CONCERNING THE PRINCIPLES OF HUMAN KNOWLEDGE, he flat-out rejects that idea: “There is no such thing as an infinite number of parts contained in a finite quantity.” At the time of this writing (November 08, 2015), I do not know if Berkeley’s argument for this claim would fail to hold in the case of composite Visibile Ideas lying one behind the other.  So for now I will leave open the possibility that perhaps an infinite intelligence, i.e., God, could perceive depth visually.  But how odd that would be, since depth is always perceived from a particular finite perspective!  (More on this later, I promise.)

Anyhow, since us mere mortals, I assume, cannot perceive an infinite number of Ideas — certainly not at the same time! –, I think Berkeley has to reject the idea that depth could be visible to merely finite intelligences such as human beings as a kind of funnel composed of composite Ideas of Vision.


No Visible Idea Of Depth Considered Either As A Line Or As A Funnel:  To sum up, then:   there is no Visible Idea of depth considered as a Line because the Minimum Visibiles composing this line cannot have structure because they cannot have parts.  And there is no Visible Idea of depth considered as a funnel because a sensible Line cannot contain an infinite number of parts.

A Berkeleyian Idea can never have anything behind it.  Possessing no element of hiddenness, it is all frontal.  “[V]isual appearances are altogether flat”, as George Pitcher puts it.

That there is no Visible Idea of depth means that we cannot see an Object at a distance — at least not strictly speaking, or, as Berkeley would put it, ‘immediately and of itself’.  For on Berkeleyian terms seeing an Object at a distance would surely have to be a combination of the visible Idea that is identical with that Object (say, the visible Moon) plus the visible Idea of depth.  But there is no visible Idea of depth available to combine with the visible Moon.

Speaking for myself, at least, I never currently experience, and do not remember ever experiencing visually, objects that are not at least some quasi-distance from me considered as the critter seeing.  Who knows how I experienced things before I was three, the age at which memories start to become permanent.  But now, at at least, the closest I can come to a visual experience of objects not at a distance (from…?)  occurs when I shut my eyes, and experience after-images floating against a dark ground which I take to be the shadow-side of my eye-lids.  (I take it that I am seeing my eyelids when I visually experience this background because, after all, I do get experience an ocher-ish translucency when light from the sun hits my closed eyelids directly.)  There is no definite distance of the afterimages from the ground behind them.  Nonetheless, behind is a distance concept — it is just that here we are talking about a degenerate case of distance, an infinitely poor cousin of the phenomenon in its full-blown reality.  Likewise, the afterimages are there before me without being any definite distance from … I want to say (fully realizing that I risk sounding like a complete weirdo without the slightest trace of academic respectability) ‘that ground of invisibility that I am qua see-er and that is directly in front of the after-images’.  Pretend for the moment that this ‘ground of invisibility that I am qua see-er’ stuff makes any sense at all or represents anything that can be communicated to a rational person.4  This would make me qua see-er a field, a background to what I experience visually, would make me, myself, a background for my after-images (what a thought!), an instance of what Lawrence Hass is alluding to when he says:

Indeed, the conditioning “background” for a perceptual figure isn’t necessarily behind it, but is often before and around it.

Lawrence Hass, MERLEAU-PONTY’S PHILOSOPHY, Indiana University Press, p. 30


But there before and directly in front of are of course distance concepts, even though these concepts as applied here are degenerate, poor-cousin instances of the real thing.5

So I am myself unable to imagine seeing an object that is not at some sort of at least quasi-distance (from me as field of invisibility in front of the after-images?).  Nonetheless, I have encountered someplace without currently being able to dig it up again, an account of a young (Asian) Indian person who regained sight after having  been blind from birth.  This person described, if I remember correctly, their vision as being like touch (a sense they would be more familiar with obviously than sight) in that (to paraphrase from memory) ‘there is no distance between me and what I see’.  Clearly, the fact that I cannot imagine this does not preclude this from being a fully accurate description of what this person experiences.  Quite possibly, then, there may be unusual, degenerate cases of visual experience that match what Berkeley takes to be proper to vision taken by itself:  i.e., visual experience of flat after-image-like patches with no depth at all (and no sense of solidity or resistance at all, if I may throw this in here now…see Berkeley’s paragraphs L and LI below) and at no sensed distance at all — not even a quasi-distance — from the experiencer.

In the normal, usual, non-degenerate case, of course, we normally do have quite a strong, powerful sensation of depth when we open our eyes.  And Berkeley would even say that there is a (weak) sense in which we do see depth then.  For in normal vision the visible Ideas suggest and are associated with Tangible Ideas, including Ideas of the body’s possible motion.  These, Berkeley argues, are so entwined with and entangled with Ideas of Sight that it is difficult to distinguish the two.  But distinguish them one can, Berkeley think, provided one gives the endeavor sufficient effort, attention, and “narrowness”.  One will then see, Berkeley is persuaded, that “. . .neither Distance, nor things placed at a Distance are themselves, or their Ideas, truly perceived by Sight” (A NEW THEORY OF VISION, paragraph XLV).  If one can be said to see Distance, or Objects placed at a Distance, it is only in the sense that through the Idea of Sight we can get to the Tangible Idea of depth.  One “mediately” sees depth in this sense — and we still call it ‘seeing’ depth because the effort to separate out the visual Idea from the Tangible Idea is so great that out of laziness and lack of ambition we label the Visual/Tactile combination with the name ‘Idea of Sight.’  Immediately, truly, and of itself, however, we do not see depth.

But as they say so often on the InterWebs, read the whole thing yourself:

L.  In order therefore to treat accurately and unconfusedly of Vision, we must bear in mind, that there are two Sorts of Objects apprehended by the Eye, the one primarily and immediately, the other secondarily and by Intervention of the former [mediately].  Those of the first sort neither are, nor appear to be without the Mind, or at any Distance off:  they may indeed grow greater, or smaller, more confused, or more clear, or more faint, but they do not, cannot approach or recede from us.  Whenever we say an Object is at a Distance, whenever we say it draws near, or goes farther off, we must always mean it of the latter sort, which properly belong to Touch, and are not so truly perceived, as suggested by the Eye in like manner as Thoughts by the Ear.

LI.  No sooner do we hear the Words of a familiar Language pronounced in our Ears, but the Ideas corresponding thereto present themselves to our Minds:  in the very same Instant the Sound and the Meaning enter the Understanding.  So closely are they united, that it is not in our Power to keep out the one, except we exclude the other also.  We even act in all respects so if we heard the very Thoughts themselves.  So likewise the secondary Objects, or those which are only suggested by Sight, do often more strongly affect us, and are more regarded than the proper Objects of that Sense; along with which they enter into the Mind, and with which they have a far more strict Connexion, than Ideas have with Words.  Hence it is, we find it so difficult to discriminate between the immediate and mediate Objects of Sight, and are so prone to attribute to the former, what belongs only to the latter.  They are, as it were, most closely twisted, blended, and incorporated together.  And the Prejudice is confirmed and riveted in our Thoughts by a long Tract of Time, by the use of Language, and want of Reflection.  However, I believe any one that shall attentively consider what we have already said, and shall say upon this Subject before we have done, (especially if he pursue it in his own Thoughts) may be able to deliver himself from that Prejudice.  Sure I am it is worth some Attention, to whoever would understand the true Nature of Vision.

A NEW THEORY OF VISION, paragraphs (of course) L and LI.  Emphasis mine.


As I continue in this project, I will have a great deal to say in a Merleau-Pontyian framework about the “Ideas” of Sight and Touch getting closely twisted, blended, and incorporated together in such a way as to generate, not just our perception of depth, but our opening out onto the brave new extra-mental world outside our skulls . . . this world so full of extraordinary things such as bark whose roughness and hardness we can see, silk whose smoothness we can see, glass whose brittleness we can see, the doorknob whose hard metallic coolness we can see, the Maple syrup whose viscosity we can see, the linen whose dryness we can see from a certain fold in it, the little mound of yellow ocher oil paint whose essential gookiness we can see, and the carpet with that peculiar woolly red.  Not to mention the bungee cord regaling our senses with that bright chemical polyester green.



Today’s homage to Plato’s SYMPOSIUM is Taylor Lautner.


Now if only a werewolf that hot were longing for me in feverish desperation, I wouldn’t mind that much the problems this would cause.  (For example, what would I do with my James Dean-like vampire boyfriend Edward?)










Let me define ‘foil’ here as ‘a person or thing that contrasts with and so emphasizes and enhances the understandability of another’.


Henceforth, following Stephen Priest, I will refer to the phenomenon discussed in the paper as the ‘ekstasis‘.


3 If I may be permitted a certain amount of snark, I will entertain the possibility that these four different possible meanings of the word ‘Line’ followed one another in a kind of tag game in Berkeley’s mind so quickly that he failed to distinguish between them.


4 Fine, I’ve laid out what I actually think. So sue me. I fully expect to forever lose any chance at all of gaining any academic respectability — even more so than if I were an artist. (I am 9/10 joking, of course, as may be evident.)


5 Interesting that visual ground/background concepts should be so closely tied to distance/depth concepts.










From 09/19/2015 to 10/25/2015:  Made numerous changes.

11/01/2015:  Added paragraphs attempting to articulate the possibility that there are unusual cases of visual experience, among some formerly blind people who have regained sight, which may involve no sensation of distance at all — not even of degenerate, poor-cousin sensations of distance.

11/07/2015:  Added a discussion of the various possible meanings of the word ‘Line’ in Berkeley’s Paragraph II.

11/08/2015:  Revised the discussion of the notion that a sensible Extension cannot be infinitely Divisible.