Some days ago I’d written an article about
the edge of the Universe. Oh, you’ve read that article? Good. In case you didn’t,
you can correct the omission here.
I was reminded of that article when I came
across someone commenting (on the response column of a comic strip) that a
particular creature looked as though it came from another world or perhaps from
“another dimension”. Obviously, this raised my pedantic hackles immediately.
Before I explain why it raised my pedantic hackles, let me repeat something I said
in that article:
Each dimension is at right angles to the others. The second is at right angles to the first, and the third to the second. A fourth dimension would be at right angles to the three we know. And a fifth dimension would be at right angles to that.
Right.
In order to understand what I’m going to
talk about next, let’s imagine that we live in a two-dimensional world. We have
length and breadth only – there’s no
such thing as height. We crawl around this world, seeing each other only as
lines and points depending on the perspective.
Now, let’s imagine a third dimension, which
is at right angles to our two. We can’t, being two-dimensional creatures,
directly perceive this third dimension. We can only perceive the cross-section
of this third dimension as it appears in our two-dimensional world. If someone
in this third dimension put his fingertip into our two dimensional world, we
wouldn’t see his finger. We’d see the cross
section of his fingertip – or, rather, the outside of the cross-section of
his fingertip; a rough circle. And we'd only realise that this circle was a
circle if we made our way around it.
Suppose now that this third-dimensional person
pushed his finger through our two-dimensional world. As he did so, the circle
made by his finger would expand and contract, and change shape, depending on
what part of the finger was passing through at that moment. And only that part
of the finger would be discernible to us. Like this:
So, ladies and gentlemen, if we were to
have a fourth-dimensional creature drop into our universe, he or she wouldn’t look like this:
Or this:
No, he or she would look like a 3-D cross-section
which would be constantly changing shape as it passed through our universe.
Correct?
Correct.
This has interesting consequences if you
think about it. Suppose we were back in our 2D world and you wanted to lock up
your money safely. All you have to do is construct a box or oblong around it,
and it would be safe. However, the third dimensional fingertip-owner could
just, you know, reach into your oblong from the top – which is, of course,
imperceptible to you – and pluck your money into his third dimension. So a
fourth dimensional creature could, you know, just get into Fort Knox and take
care of all the gold in there.
A fourth dimensional creature could also do
much nastier stuff to you. It could pluck you out of the 3D world, turn you over, and put you back again;
just like one could pick up a piece of paper, turn it over and put it down. Why
would this be nasty? It would be nasty because every single molecule in your
body would be turned the wrong way round; and for many enzymes and other
complex molecules, the right- or left-handedness of the atomic arrangement is
extremely important (they are called laevo- and dextro- depending on their
orientation).
If a 4D creature did this to you, then you’d
soon be dead because your biochemistry would cease to work in a way that
allowed you to survive in the 3D world you’d inhabited before being turned
around.
So, let’s imagine - since we can't see - what a 4 D creature would be
like. It would present as a shape-changing 3D cross section which could appear
out of nowhere, take things out of – or put things into – our discernible
space, or, if it felt like, just kill us by turning us the wrong way around.
Shapeshifter, assassin, thief, bestower of
boons – why, do you know what it would be as far as we’re concerned?
A god.
Love it. Although I wonder, wouldn't our minds be limited in what we can see, and thus process the 4th dimensional as something close to humanoid or earth bound? As in an apparition, something faint, although not necessarily it's true form.
ReplyDelete-TLMW
People misuse "dimension" to mean something closer to parallel universe or something.
ReplyDeleteI read Abbot's "Flatland" a few years ago and also a pseudo-sequel by Ian Stewart, and wrapping my head around the cross-section idea was pretty much all I got out of them.
I generally keep things simple for a reason.