Sweet+and+bitter

Sweet and bitter, cold and warm, as well as the colours - all these things exist but in opinion, and not in reality. (Democritus)
The tastes, sweet, bitter, salty; these are not seen as being in reality, because how do we know that they exist? Its all opinion. Take food for example, some people may taste a certain food and it tastes salty, but for others it may be more bitter or it could be less or more salty than the other person thought it to be. Not everyone can have the same amount of feeling as each other. This can also apply to cold and warm, these are sensory feelings, than can thus vary in opinion. In reality, is it actually hot? or is it really cold? Every individual with think differently.. so what is reality?

With the colours, how do we know that something is blue? Because someone told us that its blue. What if its actually a different colour but we were brought up thinking that its blue, maybe its something else? Where did these colours get there name? They got these names from opinion. Not in reality. Maybe our eyes are being bias, our minds could be passively changing our senses becuase we have been brought up to think one thing is another.

What exactly is reality?