The cause of Darwin's health problems has remained a mystery. Some argue that he contracted a disease while on the Beagle ; others think that his physical symptoms were the result of high levels of stress and emotional repression. In any case, the effect of his illness was to isolate him from society at Down House. He continued to see people, and his correspondence was enormous, but he spent most of his time alone or in the company of Emma. This solitude meant that he was distant from the controversies and politics of science, and was able to focus on his own theories and observations without the pressures of academic fighting or the responsibilities of teaching or mentoring. This isolation helped him develop his theory of evolution, but it may also have helped delay the time at which he finally announced it to the scientific community and the public.
By the time of his death, in 1882, Darwin was considered the greatest scientist of his age. Moreover, the very church his theory had challenged accorded him a full state funeral and burial in Westminster Abbey, near the grave of Sir Isaac Newton. Darwin’s idea was still provocative, but by the time of his death it had gained general acceptance in Britain, even among many in the Anglican clergy. Indeed, his interment in the abbey was seen by some contemporaries as symbolic of an uneasy truce between science and religion in Britain.