What was one of the main reasons for a lack of understanding of disease causes during the 19th century?

The main reason for a lack of understanding of disease causes during the 19th century can be attributed significantly to the dependence on traditional beliefs. During this period, many medical practitioners and the general population held onto long-standing theories about disease, such as the miasma theory, which suggested that diseases were caused by "bad air" or foul smells rather than microbial or environmental factors. This reliance on outdated concepts impeded the exploration and acceptance of new ideas or scientific approaches regarding disease causation.

As advances in medical science began to emerge, such as germ theory by Louis Pasteur and Robert Koch, practitioners who clung to traditional beliefs often resisted these changes due to the absence of comprehensive scientific understanding and experimentation. Thus, this cultural and intellectual inertia contributed to a slower evolution of medical knowledge regarding disease causes.

While factors like lack of technology, education, and access to medical texts played a role in the context of medical practice and dissemination of knowledge, they were not as pivotal as the deeply ingrained traditional beliefs that dominated medical understanding during this period.