Carl G. Hempel 's essay "Scientific Inquiry: Invention and Test" is a conceptual structure concerning the essence of science. To explain the structure, Ignaz Semmelweis cited basic studies on childbed fever. In order to figure out the causes of high mortality in the First Maternity Section in the Vienna General Hospital, he proposed the theory and tested it.

To figure out the reasons, he first believed "the influenza effect was the cause of high mortality rates in the first section. Semmelweis used logic to test that hypothesis. He rationalized how this epidemic was restricted to the first division without impacting the second. Why didn't it affect the whole city of Vienna like cholera? Second, overcrowding is thought to have been the cause of high mortality rates.

The number of patients in the two groups was checked. It is noted that in the second division, the number of patients was greater than those of the first division. Third, the commission report in 1846 reported that pediatric fever was caused by the harsh treatment of the patients by the medical students. He argued that the actual reproduction process was more injurious than the students' harsh treatment.

The main concepts for natural science as well as for ordinary circumstances and literary works that can be used are hypotheses and tests which make our propositions true. To investigate the issue in the Vienna General Hospital, Semmelweis pursued the same natural cycle.