The Assumption Based Life - Can You Believe Your Senses?

Can you believe your senses?miles from the earth. This means that we can
The life we lead is based on assumptions. Toonly see a star as it appeared at least 4.3 years
change your life there needs to be a questioningago. At these distances we are literally viewing
of these assumptions.the past.
Assumption One: What your senses tell you isThe other illusion is that you are looking at
truesomething 'out there'. In reality, because it is the
This is one of the easiest assumptions to questionbrain creating the images, all is happening inside
then demolish! You have five senses: sight,your brain. There is no 'out there' at all. Even the
hearing, touch, smell and taste.fisherman is perceived inside your brain. Even
Let's image that you are sitting on a riverbank.though you may put your hand out and feel the
What do you see?cold of the river, you still can only see the river
Outside of yourself you see all the elements thatfrom inside your head.
make up the scene: the river, a fisherman,Another strange effect to notice is that when our
mountains, trees and so on.retina receives the light, the image that is formed
But is this really what is going on? Light wavesis upside down. Our brain corrects this so that
from the river, the boat, the mountains, the treeseverything appears the right way up.
and all the other components of the scene travelThe sound that reaches your ears travels at 770
at a speed of 299,792,458 meters per second.miles per hour, which is considerably slower than
They then hit the photoreceptor neurones in thethe speed of light. This means that, if the
retina of your eyes. These then generatefisherman is singing, then the image of his mouth
electrical impulses that go to the brain which thenmoving reaches you much faster than the sound.
processes these impulses and creates the sceneThis effect can be noticed if you are a few
which you are viewing. If you then move yourhundred yards away from the start of an athletic
head then the brain has to update these images.race that is started by a starting pistol. As the
If the fisherman moves his boat then moregun is fired you see the smoke arise from the
updating has to take place. To you this all appearsbarrel before you hear the sound of the gun firing.
seamless with no apparent 'break' in the action.The speed of sound can also vary according to
This is because he brain updates the images sotemperature and the altitude. The higher and
rapidly that you do not notice any breaks. It iscolder the air is, then the slower sound travels.
similar to how you watch a film. A film is a seriesThe medium in which sound travels also affects
of still images flashed one after the other onto aits speed - whether this be water or glass for
screen at a speed of about 25 frames a second.example.
You do not notice each still image. If the film isYou put your hand into the river. How long does it
say, a boat crossing a river, then the illusion istake for you to feel the river? As you touch the
created of continuous movement.river, impulses travel through the nerve network
Are you seeing everything as it is in the presentin your body to your brain. Normally the rate at
moment? The light from near objects reacheswhich these impulses travel is about 331 meters
your eyes before the light from distant objects.per second. This is a bit slower than the speed of
At a speed of 299,792,458 meters a second thesound at around 346 meters per second at 82
light from the mountains and the river get todegrees Fahrenheit.
your eyes very, very fast. This means that forWhat at first appears to us as a simple situation -
most practical purposes this is not a problem. Ifsitting on a river bank, seeing a scene, being
you are playing tennis, for example, the time thataware of the smells, touching the water, thinking
the light from the ball takes to reach your eyesabout what you are seeing, is an extremely
and then the time for the image to be processedcomplex mechanism. Energy in the form of light is
by the brain and updated rapidly, followed by thebeing received by your retina, sound waves reach
time it takes for your brain to tell your arm toyour ear drums, odour molecules reach your
move is so fast that it does not prevent younose, nerve impulses enter your brain, electrical
from hitting the ball with your racket if you are aimpulses occur in your brain that we call thinking.
good tennis player. So, the illusion is created thatAll these different forms of energy travel at
everything is taking place in real time, when youdifferent speeds - yet we view it all as if it takes
can only ever deal with the past when it comesplace in the now or the present. It is our mind
to vision.that processes all this information to create what
If you move to a much wider scale - say whenappears to be 'reality' - yet the way we
you look at the sky, then the stars that you seecomprehend all this is an illusion created by us to
are so far away that the light can take years tomake sense of it all. Indeed we must make sense
reach your eye. Star distances are oftenof it all, otherwise it would be impossible to live in
measured in light years. A light year is equals 5.88this physical world. We need to be able to walk,
million million miles. This is how far light travels inavoiding objects, react to the sound of a roaring
one year at a speed of 186,282 miles per secondlion so that we can take flight before it pounces
or 299,792,458 meters per second. The starand eats us.
nearest our sun is Proxima Centauri which is 4.3It is our brain that makes sense of everything we
light-years from the Sun. The Sun is 93 millionsee - but can we trust our own brain?