The Sense Beyond Common Sense
it is often said
common sense is not very common implying
that having
good common sense is an intellectual
privilege
we also think common sense qualifies as
to
analyze and comment on anything
when a survey was conducted in australia
on the public perception
of climate change almost one third of
the respondents
commended that they don’t think climate
change is happening
and they attributed the reason for their
conclusion
on common sense it’s just common sense
that’s what they said
being a person who has been learning
doing and teaching science
i would say that you need a sense beyond
common sense to understand science
i would even argue that common sense is
a hurdle for understanding certain
things
let’s have a look at the famous
experiment of the following
objects originally done by galileo
galilei
take two water bottles one of them is
empty
and the other one is filled if you allow
them to
fall from rest from the same height
which one of them would hit the ground
at first
just think about it if you remember your
school lessons you would say
that both of them would hit the ground
at the same time
but just introspect and ask your common
sense
what it says to you about the outcome of
this experiment
if you ask me i still feel amused to see
the result of
this experiment when it is performed in
real
simply because it doesn’t appeal to my
common sense
the problem is we are thinking in terms
of mental images
when we think about something we try to
visualize it in our mind
that’s part of our common sense we think
and talk about things
which we can feel inside but there are
many serious issues with visualizing
things in our mind that way
one of the issues is regarding the
inherent limitation
in assessing the magnitude of physical
quantities
beyond a particular range we are
used to the magnitude of physical
quantities in a particular range
if it is smaller or larger than those
limits
we tend to lose the feel for this
consider the example of weight we all
have a certain feel about the weight or
heaviness
of objects when i ask you what is the
weight of an orange you have a feel
inside
how much an orange would be but i want
you to note the difference between
giving a number and
feeling it inside you won’t be able to
say exactly how many grams an orange
would be
but you have a feel inside the same way
you have a feel on how would
a 20 liter can of water would weigh and
you can also have
a feel of the comparison between the
weight difference between an
orange and the can of water but do you
have a feel
about the weight of a bacterium well i
can give you the numbers if you want
a bacterial cell is typically around one
trillionth of a gram in weight
but can you feed it inside a bacterial
cell is
hundreds of times heavier compared to a
virus but can you feel the difference
between
the masses of a virus and the bacterium
say i tell you a truck is 20 tons in
weight can you
feel how that heaviness is the same way
you felt the heaviness
of an orange now consider numbers if i
say there are
5 apples to your left side and 3 apples
to your right side
you know a feel of the difference
between these two numbers
right but if i say there are thousand
apples on one side and two thousand
apples on another side
can you have the feel of that numbers
both of them are essentially a heap of
apples to you right now
maybe one heap is bigger than the other
but you simply lost the feel for that
number
what about time all of you have a feel
about how much time has passed since you
started listening to the speech
a few minutes with some reasonable
margin of error
but a honey bee flutters its wings 200
times a second
do you have a feel about the sharpness
of the time interval between two
successive flaps of its wings
what about the difference between two
thousand years and three thousand years
you know the difference between the
numbers two thousand and three thousand
when they are
written or told but i want you to
introspect
about the difference in the time periods
of two thousand and three thousand years
aren’t we just comparing the visual
appearance of these numbers when they
are written
or the auditory feel of these numbers
when they are told
do we actually have the feel of the
magnitude of the time involved
to clarify this let me show you this
what comes to your mind when i say 0
is it this if it is just think about it
a little bit further
is this 0 or is this really
a symbol that represents the idea of
zero
this may invoke the concept of zero in
your mind but this is not
zero by itself what about the word me
nothing if i ask you to imagine nothing
whatever comes to your mind is not
nothing
because if something comes to your mind
it is something rather than nothing
by now if you are feeling that i am
playing with words really i am not just
think about it
another serious issue is regarding the
misconception
about the absoluteness of certain
quantities
time for example is commonly taken as an
absolute quantity
it’s always taken for granted that time
flows equally for all
when i say 10 seconds you understand it
there is no ambiguity involved
but it’s based on the assumption that
the duration of one second for me
is exactly equal to the one second of
yours
or in other words we assume that your
cloak and my clock
tick at the same rate but it has been
proven many times
with precision that it is not the case
if you compare
a stationary cloak with a moving clock
a moving clock will appear to be slower
compared to a stationary clock of course
the difference may be negligibly small
for ordinary relative speeds of motion
but negligible
is not zero and the difference is there
it’s not just about
time intervals for a moving observer
length and mass are also relative
it’s one of the key implications of the
theory of relativity in physics
see it means things which we can have a
feel for
are actually relative and not absolute
but in nature there are certain
quantities that does not depend on
observer but gives you the same result
whenever they are measured such
quantities are called
natural constants or fundamental
constants the speed of light in vacuum
may be the most common example all
measurements of the speed of light will
give you the same result
irrespective of whether the observer is
stationary
or moving with light or moving against
light
of course it’s quite counterintuitive
how can something
appear to have the same speed when you
are moving
at it or when you are moving with it
there are many such natural constants
like gravitational constants planck’s
constant etc
which are absolute and will give you the
same value whenever they are measured
wherever they are measured and whoever
measures it most of them
have dimensions that cannot be
visualized or felt
in our mind you may be able to visualize
heaviness
length distance time period
brightness etc but how would you
visualize a quantity
that is force multiplied by the square
of distance
and then divided by the square of time
what kind of a quantity that would be
well that is the dimension of
gravitational constant which is a
fundamental constant that will give you
absolute value for its measurement see
some things which we think
are absolute are really relative and
some other things which are actually
absolute
are beyond the grasp of our mind i hope
you understand the point i’m trying to
try
to add to this let’s also have a look at
our available sources of information
our primary sense is vision where we
receive information about our
surroundings through light
light is essentially an electromagnetic
wave which is nothing but a parade of
oscillating
electric and magnetic fields depending
on the rate of this oscillation called
the frequency
electromagnetic waves vary in nature
from a wide spectrum of frequencies from
high frequency gamma rays to low
frequency
radio waves our eyes can sense
only a tiny band of frequencies which
are around a few hundred terahertz
and we call those frequencies by the
name visible light
the same is the case with sound sound
is essentially a pressure verb created
by
vibration of objects from a wide
possibilities of
frequencies of vibration our ears can
detect
only a particular band of frequencies
from 20 hertz to 20
000 hertz if it is not in this range
you don’t hear anything even if there is
sound
the moral of the story is the nature
doesn’t
care about how human brain thinks
it has its own ways to work while
discussing quantum physics theory of
relativity etc scientists often say that
these ideas do not agree with our common
sense
even i say it in my classrooms
but there is one important point to be
added here
is it mandatory that these mechanisms of
nature
should agree with our common sense who
are we
homo sapiens are one among the millions
or billions of species of organisms
living on the surface of this planet
we think homo sapiens are special simply
because we are the homo sapiens
we evolved a few hundred thousand years
ago on earth
with bodily adaptations suitable for
surviving
in the circumstances of that time
our circumstances have changed
drastically during these years
but our brains haven’t it was too small
a time period for biological evolution
to make
considerable changes on our brains or in
other words
a cavemen of the paleolithic age where
as
intelligent as we are today or we are
only as intelligent as a caveman
from the paleolithic age whichever way
you want to put it of course
we have excellent cognitive capacities
compared to other species of
living beings but they are not custom
made to comprehend everything
that’s what calls for science with
science we have devised
tools to transcend our senses methods to
circumvent the limitations of our own
common sense
so that we can unravel the secrets of
this universe
to see what the sense of science has
done to humanity
let’s have a look at history as we said
history of homo sapiens extends around
200 000 years back
but let us stick on to the history of
human civilizations
invention of agriculture is considered
to be the beginning of human
civilizations
because that was what made us capable of
settling down
and building up large societies
evidences tell us that
agriculture is not more than 10 000
years old
but even that number is too large for
our brains to visualize
as we have discussed earlier therefore
let us shrink this history of 10 000
years
to one single year that means in this
calendar
humans invented agriculture on the dawn
of a january 1st
and the present day is close to the
midnight of december 31st
remember in this special calendar every
day is equal to
27 years in actual history now let us
try to place some significant inventions
or discoveries
that change the shape of humanity in
this calendar
how would you expect them to look like
this is it
see how crowded those discoveries or
inventions are
in the last fortnight of this calendar
electricity
automobiles computers x-rays even the
seventh
planet in the solar system almost every
technology which we think are
fundamental to humanity now
came to existence only in the last
minute in this drama
now if you look for a reason behind this
crowding of events the answer lies in
the history of science
we are able to accomplish feats after
the discovery of the method of science
that discovery didn’t happen on a single
day but was in fact a collective
realization
from a long history in that sense i
would say that the best
discovery of humans was the best method
to find out truths
which we call the method of science
today so
i vote for the sense of science over
common sense
thank you