Not really, many things you can observe and learn yourself fairly quickly. Some others are very hard to observe yourself (e.g. the poisonous effect of lead) bu

Not really, many things you can observe and learn yourself fairly quickly. Some others are very hard to observe yourself (e.g. the poisonous effect of lead) but by now they are embedded into the collective consciousness. My worry is with things that are neither. In this particular context these are things that you know if you grow up in a rich/middle-class family, but hard to come by if you become rich/middle-class later in life.