1. It was just sheer pigheadedness on his part.

2. I am not sure whether this was courage or pig-headedness.

3. Hereditary aristocracies, Douthat writes, suffer from stupidity and pigheadedness, while one-party states do so from ideological mania.

4. The whims of Roman Abramovich, the pigheadedness of Tom Hicks and the predatory stalking of Alisher Usmanov are in danger of giving the Glazer family a good name, if only by default.

5. Perhaps not. Some academics have recently suggested that a scientist's pigheadedness and social prejudices can peacefully coexist with — and may even facilitate — the pursuit of scientific knowledge.

6. In the laboratory, this is labeled confirmation bias; observed in the real world, it's known as pigheadedness.