Answer
The Royal Society was a learned society in London, founded in the 17th century. It focused primarily on scientific and mathematical research. Hieronymus Bosch, a Dutch painter known for his fantastical and symbolic works, lived in the 15th and early 16th centuries. He belonged to the Brotherhood of Our Lady, a religious organization based in's-Hertogenbosch, Netherlands. Therefore, Bosch was indeed not a member of the Royal Society.