0:02 Imagine that this folder is a
0:05 dimensional plane. Now, assuming that it
0:07 has no height and no depth, what would
0:09 this mean? It would mean that it's a
0:11 one-dimensional world. So, if
0:13 hypothetically an organism was living
0:15 inside of it, it would only be able to
0:16 move in a linear path forward and
0:20 backwards in a straight line. Now, if we
0:23 go to the second dimension, we have two
0:25 dimensions. We have width and we have
0:27 length. So hypothetically, if an
0:29 organism lived inside of here, then it
0:31 would be able to move up, down, left,
0:34 right, and anywhere else in between. And
0:36 a two-dimensional world is comprised of
0:39 an infinite series of one-dimensional
0:42 worlds stacked upon each other. Just as
0:44 our three-dimensional world, which has
0:48 depth and length and height, is
0:50 comprised of an infinite series of
0:54 two-dimensional worlds. So this now that
0:55 I have stacked many folders upon each
0:57 other. We have three dimensions. We have
1:00 depth, we have length and we have width.
1:02 Now what happens if you keep going on
1:03 from here on out? We would have a
1:05 four-dimensional world. But what exactly
1:08 is a fourth dimension? In order to
1:09 understand this, we need to understand
1:12 how dimensions are perceived. We live in
1:14 the three-dimensional world. But despite
1:17 that, we actually view things to be
1:19 two-dimensionally. Take a perfect sphere
1:21 for example. If you're looking at a
1:23 sphere, it looks just like a regular
1:25 two-dimensional circle. The only way
1:27 that you can tell it's a actual sphere
1:29 instead of a circle is because of the
1:31 hues of light on it. So, just like in a
1:34 two-dimensional world, if a um organism
1:36 in the two-dimensional world was looking
1:39 upon a circle, it would the light would
1:41 make it appear to be lighter at one end
1:43 and darker in the middle.
1:46 Also, if you if an object is moving
1:48 farther closer and farther away from
1:49 you, you don't actually perceive that
1:51 it's getting closer and farther away,
1:53 you see that it's getting smaller or
1:55 larger, and then you assume that it's
1:58 getting either farther away or closer.
2:01 But let's say an object was to grow in
2:04 perfectly equilibrium so that it was
2:06 growing at the same speed that it was
2:08 shrinking as you move it farther away.
2:10 then you would not be able to tell
2:12 without any lights or uh if there were
2:15 details on the object that it's moving
2:17 or growing at all. You may have assumed
2:19 that since we perceive things to be in
2:22 two dimensions that a two-dimensional uh
2:25 organism would see in one dimension. So,
2:28 as we're watching this uh rubber band
2:31 expand, as it moves farther away from
2:32 this little uh organism in the
2:35 two-dimensional world, it's does not
2:37 actually perceive anything is happening
2:38 to it because it's growing at the same
2:41 speed that it's moving farther away. But
2:43 since we can actually see it from the
2:44 three-dimensional world and perceive
2:47 things to be in two dimensions, we can
2:50 see things to for how they actually are.
2:52 The reason that the two-dimensional
2:54 organism doesn't see things the way they
2:55 really are is because the
2:57 two-dimensional organism sees things in
2:59 one dimension just how we
3:01 threedimensional creatures see things in
3:03 two dimensions. So, in a way, we don't
3:05 really see our world the way it truly
3:07 is. A four-dimensional creature,
3:09 however, seeing our three-dimensional
3:11 world in three dimensions would be able
3:13 to see through things. You'll be able to
3:15 see absolutely everything just as we
3:18 could see if there was uh several
3:22 organisms spread along a 2D um
3:24 environment on your floor. You would be
3:26 able to see inside houses. You would be
3:28 able to see inside of people. So if a
3:30 two-dimensional world, a flat surface is
3:33 just made of an infinite amount of uh
3:36 lines, then the 3D world is just made
3:39 out of an infinite amount of planes. So
3:42 the 4D world logically is made out of an
3:45 infinite amount of 3D objects though
3:48 they're not just put together like um
3:50 you would like building blocks. It's
3:52 that's not how the 4D world is. That
3:55 would just be 3D again. So in order to
3:58 understand this we need to understand
4:01 the logical progression of mathematics
4:04 in our world.
4:05 Imagine that this connects piece
4:07 represents the first dimension. It's
4:09 simply a straight line, which is
4:11 basically what the first dimension looks
4:15 like. And if you add three more of these
4:17 straight lines and connect them to so
4:21 that adjacent sides are perpendicular
4:23 and opposite sides are parallel, then
4:25 you have the basic shape of the second
4:27 dimension. You have a square. Now if you
4:30 keep going from here and you add four
4:32 add it so that there's a total of four
4:35 squares and all adjacent sides are
4:37 perpendicular and all opposite sides are
4:41 parallel then you end up with obviously
4:43 obviously
4:46 a cube.
4:49 So if you tried to keep going from here
4:51 and you would have a fourdimensional
4:53 basic shape you would have a what's
4:56 called a tesseract. Now I cannot show
4:59 you a test raact but you need to
5:01 understand that it's basically four
5:04 cubes that are within each other that um
5:07 have all adjacent sides perpendicular
5:10 and all par and all opposite sides
5:13 parallel yet there are three lines
5:16 connect four lines connecting to each
5:20 vertex. So a tesact would look somewhat
5:22 like this picture. Now that that's not
5:24 exactly what it looks like because this
5:27 is a twodimensional depiction and
5:28 obviously not all the lines are
5:31 straight. So I cannot show you what a
5:33 cessoract actually looks like because we
5:35 cannot perceive things in the third dimension.
5:36 dimension.
5:39 You cannot even imagine what a tesseract
5:41 looks like. You cannot physically you
5:43 cannot in your mind picture the fourth
5:46 dimension or a fourthdimensional shape.
5:47 And you can keep going on from the
5:49 fourth dimension even. You can go to the
5:50 fifth dimension, the sixth dimension,
5:53 the 71st dimension. It doesn't matter.
5:55 Theoretically, there are an infinite
5:57 amount of spatial dimensions. A common
5:59 misconception of the fourth dimension is
6:02 that the fourth dimension is time. Now,
6:05 while some argue that by going forward
6:07 and backwards in time, if you move
6:09 forward the same distance and backwards
6:12 the same, then you would end up in the
6:13 same place you started, just like in the
6:15 fourth dimension. And while that may
6:17 seem logical, if you think about it, it
6:19 really doesn't make sense. If you imply
6:21 that the fourth dimension is actually
6:24 time, well, first of all, time is not
6:25 spatial. There's a difference between
6:28 space and time quite obviously. And
6:30 assuming that all dimensions are
6:33 according to a pattern, then that
6:35 doesn't really make sense either because
6:38 saying the fourth dimension is time,
6:41 every dimension has time in it. So that
6:43 would mean that the fourth dimension is
6:44 special in some way, which doesn't
6:47 really make any sense. Another reason
6:50 this doesn't make sense is that we very
6:53 very very slightly travel through time
6:56 whenever we move due to the distance um
6:59 that light takes to get to our body.
7:01 If a group of astronauts were to get in
7:03 a spaceship and they were to go very
7:06 very very close to the speed of light,
7:07 then they would and they they went
7:11 around in this um impossible nearly the
7:12 speed of light spaceship for a few
7:14 months and then afterwards they returned
7:16 to Earth. They would find that Earth had
7:18 actually progressed a few years. So they
7:21 had moved forward in time by moving that quickly.
7:23 quickly.
7:25 Another interesting concept involving
7:27 the fourth dimension is that many
7:30 physicists and even mathematicians uh
7:32 may say that the dimensions are very
7:35 very slightly curved because if you
7:37 really think about it nothing can be
7:40 truly absolutely infinite. So imagine
7:43 that a the first dimension the line is
7:46 just very very slightly curved so that
7:50 after a very long time it will um end up
7:54 creating a circle. So um as suggested by
7:56 many physicists if you keep going in the
7:58 same direction then you will end up
8:01 where you are where you started after a
8:04 very very long amount of time obviously
8:05 and the same thing would happen to the
8:07 second dimension. If it's just a square
8:10 and then you extend it very very
8:12 slightly in a curve then it will
8:15 eventually make a sphere. And the same
8:16 thing happens in our dimension except it
8:21 will form a very very slightly curved um
8:23 third dimension which will form a
8:26 four-dimensional universe basically. So
8:28 what this kind of means is that our
8:31 three-dimensional world is within a
8:32 four-dimensional world and a
8:34 four-dimensional world is within a fifth
8:36 dimensional world and so on.
8:38 Now, I did say that nothing can be truly
8:41 infinite. But if this is true and a
8:43 dimension is really within another
8:44 dimension within another dimension
8:46 within another dimension, then I'm
8:48 implying that there's an infinite amount
8:50 of dimensions, which is the only problem
8:52 I really have with the theory. I'm not
8:55 sure if it ever stops or if infinite
8:57 infinity is really even possible. We
9:00 don't know that. Thanks for watching my
9:01 video and I hope this gave you a better
