Category Archives: Space

Seeing things at more than one time

Take a look at the video below (the noise might be quite loud; it is from the spinning):

**And here is the video of it provided by Daniel Palacios (the artist) himself (I prefer my own for THIS post because it shows only on what I’m discussing here): http://vimeo.com/12075151 **.

This is one of the exhibits at the Science Gallery, Trinity College, Dublin in March 2013. This is a single elastic rope being spun rapidly by two motors attached to each of its ends. There’s more to it than that — the motors are set off and altered by movement around it — but what is most important is this:

(a) If you are seeing this device, then you are seeing a single rope spinning rapidly through a region of space.

(b) What you seem to be seeing is something occupying the surface of a three-dimensional volume within that region. This surface includes more than one point in space, e.g., in the following picture, it includes the area encompassed by the circles ‘A’ and ‘B’.

spin1

This volume that you seem to see is constantly changing. If you’re seeing the rope, then it is because of the motion of this rope. However, at any one time, the rope is not itself stretching out over that surface it seems to fill. The rope is just a relatively thin (yet elastic) rope which spins quickly about a horizontal axis. And because of that spinning then, at one time, it is at ‘A’ and, at another time, it is at ‘B’.

What you see in this video is — obviously — not just what you are seeing when you look at this for real. But when you go and look at the spinning rope — not through YouTube, but just standing in front of it and seeing it — you see in all important respects the same thing as in this video: the apparent filling of the circumference of a volume by something in motion, something which turns out to be the rope. Go and see — visit the science gallery [1].

The Time of What you See

If you see this rope moving like this, and you do see it as being in two places  (e.g., ‘A’ and ‘B’) — then

1. You seem to see the rope occupying different locations in space.

What is moving — in reality, a single rope — seems to be occupying two places at the same time, i.e., it seems to occupy two points in space simultaneously.

However, the rope cannot be occupying these two places, or any like them, simultaneously[2]. Instead, this filling of the volume is only from the movement of the rope. The rope is moving from one of these points to the other of these points, but it is never at each at one time. The rope is occupying this surface over or through a multiple of times. And you see it doing that — you see it filling this surface over a multiple of times.

This means that this appearance of simultaneous occupancy of these spaces is not of real simultaneity. That in itself doesn’t bother me — and I don’t think it should bother anyone else: ‘apparent simultaneity’ in my view is not an ‘appearance’ at all but the non-appearance of actual duration (read more on this in my 2010a ‘Complex Experience, Relativity and Abandoning Simultaneity’, or even my PhD thesis, where I go into more finicky detail).

It also means something else.

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Spatial illusions and temporal illusions (II): What Really Surrounds You

Previous: perceiving three dimensions and geometric optical illusions

In my view, a good explanation — or a good philosophical or metaphysical explanation, anyhow — is a general one. It does not just explain one particular thing; it explains a multiple of things. I think there is a limit to any such explanation, due to the particularity of everyday things, though. The thisness — or however you might put it — of any particular object, e.g., this particular orange, means that explanations of how this orange comes about, and/or accounts of its current constitution, cannot be generalised to all oranges, or even a non-singular sub-set of oranges.

A lot of the individuality of that orange, however, can be captured by simply pointing out its unique location in space and in time. The orange is just like other oranges, except it is at this time and this place.[1]

Still, I think the better explanation is the more general one. It is not the firefighting one, the ad-hoc, we-need-it-now/nevermind-then/nevermind-later. It is also not the one which explains only how this orange came to be on my table, but also how oranges come to be on tables in general.

Similarly, if I introduce a concept of space in order to explain a particular geometric-optical illusion, then it is a weakness of my theory that this concept only covers that illusion, doing nothing for other kinds of experience, illusions, hallucinations or otherwise. It is being introduced ad-hoc, and only specifically for that illusion. In contrast, if I introduce a concept of space which is already there, or can be effectively generalised to other things, then there is nothing ad-hoc about this.

So what concepts of space are there already, which might be used to explain geometric-optic illusions?

What Surrounds You?

Let’s start with your idea of space.

If I ask you, what surrounds you, what will you say?

There are two ways I think I might answer this question.

  1. First, I might simply describe what I am aware of, aware of without any obvious reflection or mediation. I just look around me, which is so far as I can tell a simple turning of my neck and keeping open of my eyes, and say: there’s this, and this, and so on.
  2. Second, I might reflect upon it and think about what there has to be and what there can be around me.

‘1’ can be understood as giving a phenomenological description — a description of how things seem. I offer a description even if I am a dying astronaut hallucinating in the depths of a void[2], i.e., where nothing is around me, but there seems to be something.

‘2’ can be understood as doing metaphysics, i.e., formulating a metaphysical theory or speculating about the metaphysical status of the spatial arrangements of things around me. So, for example, if I believe that I am hallucinating, or am under an illusion, this would  affect what I say when asked ‘what surrounds you?’. I would not draw on how things seem to me, since I believe this to be an hallucination or something similar. I might say, in the right circumstances, something like ‘I seem to be surrounded by stars, distant hills, the song of crickets but I am under an illusion’. I’m really surrounded by four illuminated walls in a dark room’.

‘2’ is at least as important as ‘1’ in answering this question. If I answer ‘I’m surrounded by #’ then I don’t mean just what I seem to be surrounded by. I mean what I am surrounded by.

So, with geometric-object illusions, I can describe what I seem to experience and what I think is out there. The illusion is the clash of those: e.g., (from last post) there seem to be uneven lines but the lines are even; there seem to be small circles and big circles, but the circles are all the same size.

So, when I ask you, what surrounds you, what will you say? And in particular, what HAS to surround you? What can’t be surrounding you? And how does this correspond to your experience?

My answer, like many of my answers, is that it depends on how one thinks about time, which requires a lot more detail. For now, we can draw an analogy between the different somewhat live ways of thinking about time and imaginary ways of thinking about space.

Roadrunner: The Painted Tunnel on the Cliffside

Wile E Coyote paints an image of a train tunnel on a sheer cliff side and waits for Roadrunner (and lunch).

Clearly, his plan is: the roadrunner sees what seems to be space stretching into the cliff, tries to run into that space, fails(because there is no space stretching into the cliff), and is knocked out (and becomes lunch),

However, instead: the roadrunner sees what seems to be space stretching into the cliff, runs into that space, does not fail, is not knocked out (and escapes).

Further: Wile E Coyote, puzzled, tries to run after the roadrunner, fails, and is knocked out.

One way to look at the difference here is that roadrunner and the coyote occupy different worlds with different kinds of space in their counterpart areas. In the roadrunner world, space stretches into the cliff; in the coyote world, it doesn’t.

In that case, the apparent spatial extension into the cliff is, in the roadrunner world, not an illusion whereas the apparent spatial extension into the cliff, in the coyote world, it is an illusion.

Something similar can be said of the phenomenology and metaphysics of time.

Notes

1. One might be tempted to then say that this is all there is to the ‘thisness’ of any particular orange, or any object. Some metaphysicians do just this; some bundle theorists hold that all there is to an object is the instantiation of properties located at the places and moments in which it exists.

2. For related discussion of hallucination when test pilots are under extreme pressure, see this episode of RadioLab: http://www.radiolab.org/2006/may/05/out-of-body-roger/