How do we know if what we see is the same as what other people see?

Question: How do we know if what we see is the same as what other people see?
- Keywords:
  philosophy
Asked by zoesmith to Angela, Gopal, Hannah, Becky, Vince on 24 Jun 2013.
- Gopal Ramchurn answered on 24 Jun 2013:
  
  We can’t be sure of it – except by communicating what we see to other people. Apparently in some parts of Africa, some tribes do not see colours as we see it – they have grown up in such a way that their mind sees things differently from us. The human brain is what processes all the information coming through our eyes/ears and tells us to associate a shape/name/colour with the information coming in … and this association is dependent on what our parents/the world teach us when we grow up. If no association is made, we won’t ‘see’ certain things. We probably don’t all see a colour the same way for example (e.g., i often see people not being sure if something is red or orange).

Question: How do we know if what we see is the same as what other people see?