Matthew knew that phrenology was nonsense, and yet, years later, he found himself making judgments similar to those made by his father; slippery people looked slippery; they really did. And how we become like our parents! How their scorned advice - based, we felt in our superiority, on prejudiced and muddled folk wisdom - how their opinions are subsequently borne out by our own discoveries and sense of the world, one after one. And as this happens, we realise with increasing horror that proposition which we would never have entertained before: our mothers were right!