We are all philosophers. I never stop thinking. And wondering. So philosophy was a natural target for study in retirement. I had no desire to go too deep but just wanted an introduction to the scope of the subject studied by university students. So I read about the ideas of several of the great philosophers like Plato and Aristotle together with books by present day philosophers like A C Grayling, Colin McGinn and Alain De Bottton. But perhaps my most enjoyable project was to study the life and works of Bertrand Russell. This included biographies of the great man, his own autobiography - a great read, and his History of Western Philosophy.
How much of all this I have absorbed is impossible to assess. And I am really not sure what effect all my reading has had on my own preconceived ideas. But when one gets an insight into a truly great mind, it truly is something special to behold.