Felt he was just using good Hippocratic ideas of observation and diagnosis, but was quietly changing the way illness was diagnosed and how cures were attempted
The English Civil War in 1642 cut Sydenham's studies short, but this may have been helpful as it meant he began his studies and gained familiarity with the basics, then was more free to go out and seek his own ideas
Each disease was different and needed to be individually identified, each disease also required a different cure, believed in observation and diagnosis like Hippocrates, letting nature take its course with illness rather than trying to cure everything at random, encouraged taking the pulse as a method of diagnosis
Sydenham took advantage of new ingredients being discovered all over the world, believing that the environment would contain not only the disease but also the cure, as part of God's plan
Sydenham's work can be seen as part of the early Enlightenment, with the Royal Society of London for Improving Natural Knowledge being set up in 1660 to support the development of new scientific ideas
Ordinary people and many doctors still believed superstitious and ancient ideas about medicine and disease, and theories like miasma were still thought to cause illness, meaning many treatments remained ineffective