Alain de Botton explores why we have dreams:
Most of the time, you feel in charge of your own mind.
You want to play with some Lego? Your brain is there to make it happen. You
fancy reading a book? You can put the letters together and watch characters
emerge in your imagination.
But at night, strange stuff happens. While you’re in bed,
your mind puts on the weirdest, most amazing and sometimes scariest shows.
[…]
In the olden days, people believed that our dreams were
full of clues about the future. Nowadays, we tend to think that dreams are a
way for the mind to rearrange and tidy itself up after the activities of the
day.
Why are dreams sometimes scary? During the day, things
may happen that frighten us, but we are so busy we don’t have time to think
properly about them. At night, while we are sleeping safely, we can give those
fears a run around. Or maybe something you did during the day was lovely but
you were in a hurry and didn’t give it time. It may pop up in a dream. In
dreams, you go back over things you missed, repair what got damaged, make up
stories about what you’d love, and explore the fears you normally put to the
back of your mind.
Dreams are both more exciting and more frightening than
daily life. They’re a sign that our brains are marvellous machines – and that
they have powers we don’t often give them credit for, when we’re just using
them to do our homework or play a computer game. Dreams show us that we’re not
quite the bosses of our own selves.
Neuroscientist David Eagleman explains why we can't
tickle ourselves:
To understand why, you need to know more about how your
brain works. One of its main tasks is to try to make good guesses about what’s
going to happen next. While you’re busy getting on with your life, walking
downstairs or eating your breakfast, parts of your brain are always trying to
predict the future.
Remember when you first learned how to ride a bicycle? At
first, it took a lot of concentration to keep the handlebars steady and push
the pedals. But after a while, cycling became easy. Now you’re not aware of the
movements you make to keep the bike going. From experience, your brain knows
exactly what to expect so your body rides the bike automatically. Your brain is
predicting all the movements you need to make.
You only have to think consciously about cycling if
something changes – like if there’s a strong wind or you get a flat tyre. When
something unexpected happens like this, your brain is forced to change its
predictions about what will happen next. If it does its job well, you’ll adjust
to the strong wind, leaning your body so you don’t fall.
Why is it so important for our brains to predict what
will happen next? It helps us make fewer mistakes and can even save our lives.
[…]
Because your brain is always predicting your own actions,
and how your body will feel as a result, you cannot tickle yourself. Other
people can tickle you because they can surprise you. You can’t predict what
their tickling actions will be.
And this knowledge leads to an interesting truth: if you
build a machine that allows you to move a feather, but the feather moves only
after a delay of a second, then you can tickle your- self. The results of your
own actions will now surprise you.
Particle physicist and cosmologist Lawrence Krauss
explains why we're all made of stardust:
Everything in your body, and everything you can see
around you, is made up of tiny objects called atoms. Atoms come in different
types called elements. Hydrogen, oxygen and carbon are three of the most
important elements in your body.
[…]
How did those elements get into our bodies? The only way
they could have got there, to make up all the material on our Earth, is if some
of those stars exploded a long time ago, spew- ing all the elements from their
cores into space. Then, about four and a half billion years ago, in our part of
our galaxy, the material in space began to collapse. This is how the Sun was
formed, and the solar system around it, as well as the material that forms all
life on earth.
So, most of the atoms that now make up your body were
created inside stars! The atoms in your left hand might have come from a
different star from those in your right hand. You are really a child of the
stars.