Answer by Dharmesh Dubey:
Do you see the same colour of your blood as I do?
What if our colour wheels are rotated with respect to one another?
Let's consider this with an example or say an experiment.
A small child is made to wear a special kind of glasses, which changes his colour perception. It is such that the red colour colour changes to blue (i.e. it looks blue to him), green to red and blue to green.He has to wear the glasses permanently. The effect caused by the glass is not told to anyone(The child does not take off the glasses, so he couldn't recognize the difference either).
So, when you will see this
he will see this instead.
But when he asks, what colour is it, people will say 'red', as that is what they see. For example, the teacher tells that this rose is of 'red' colour.
But, what he is actually able to see is this
So, in his view this colour is 'red' , and thus, every time when he observes this colour he will call it red, although what he observes is actually blue according to you. But you don't know that and neither does he.
Similarly, for the other colours
when you see this
what he is observing is
But both of you call it as green.
And similarly, when you see
he is observing
but again, both term it as blue.
And so, he has a name for all the colour's he observes, but the list may not be same as yours. For the example taken here, his list of colours along with what you see is-
So, when both will say "The sky is blue", both are actually observing different colours, but have a common name for that. (According to your list, he is observing 'green' colour). So the system works perfect, and nobody(including the boy), comes to know that he is having a colour perception changing glass.
Now consider this, what if all of us have such inbuilt glasses inside our brains, so that we all perceive colours differently. Also ,there can be a lot of possible combinations. So a red coloured object for me, may look different to you, and could be still different in colour for someone else. But still, all of us will call it 'red', as that is the name of that colour according to all of us. So, we cannot actually detect that we all are watching the same colour of an object.
Is it just a theory, or does it have a scientific base?
Actually it does : Colour perception emerges in our brains in response to our experiences of the outside world, but this process ensues according to no predetermined pattern. When we're born, our neurons aren't configured to respond to colour in a default way,instead, we each develop a unique perception of colour. So our colour perception could be different.
So, your colour red could really be my colour blue.
So moving back to my question,"Do you see the same colour of your blood as I do?"