Dr. Nick Axten, 76, said he needed to “think hard and hard” over the intervening decades.
In 1970, Dr. Axten received a prestigious Fulbright scholarship to pursue a doctorate in mathematical sociology at the University of Pittsburgh in the United States. But after five years he returned to the UK with an unfinished PhD.
Today the University of Bristol awarded him a PhD in front of his wife Claire Axten and their 11-year-old granddaughter Freya.
Dr Axten said: “What I was trying to do in the early 1970s was exceptionally difficult.
“Some problems are so big that it takes most of your life to understand them. They need to think a lot. This one has taken me 50 years.”
Dr. Axten’s research, which he hopes to publish, builds on ideas he was working on in the US five decades ago.
It is a new theory to understand human behavior based on the values that each person has, which he believes has the potential to change the vision of behavioral psychology.
When he began his university career at Leeds in 1967, the men wore long hair and the women wore miniskirts.
Smoking inside university buildings was the norm, and personal computers were still science fiction.
“It was still flower power and there was a revolutionary feeling. It was the time of the Vietnam War, Paris, Prague and student sit-ins,” she recalled.
“Jack Straw was president of the Leeds students’ union. Sociology and psychology were suddenly booming topics. I went to study them because I wanted to understand people.
“I have loved being a student at the University of Bristol again.
“All the other philosophy grad students were around 23 years old, but they accepted me as one of their own.
“They are intelligent people full of ideas and I loved talking to them, especially in the pub in the evening.
“Doing a PhD is very hard work, but it has been brilliant.”
Dr Axten came to the University of Bristol in 2016 to do a Master of Philosophy, aged 69. He then studied for a Ph.D. in Philosophy at the same university, finishing in 2022 at age 75.
His Bristol University supervisor, Professor Samir Okasha, said: “Nick was an incredibly enthusiastic, energetic and committed student during his time here.
“It’s great to see him graduate half a century after his original PhD began.”
During a varied career, Dr Axten lived throughout the UK and was the creator and lead author of the Oxford Primary Science teaching programme.
He lives in Wells, Somerset with his wife, is the father of two children and has four grandchildren.