In the history of microbiology, which scientist is famous for formulating postulates that proved that specific microorganisms cause specific infectious diseases?

Introduction / Context:
This question is from general science and microbiology. It asks you to recall which scientist gave strong experimental proof that specific microorganisms cause specific infectious diseases. This is closely linked with the germ theory of disease and the development of modern medical microbiology.

Given Data / Assumptions:
- The focus is on proving that microorganisms cause disease. - The options are van Leeuwenhoek, Koch, Fleming, and Pasteur. - The item refers to experimental proof through systematic rules or postulates.

Concept / Approach:
Robert Koch, a German physician, formulated a set of criteria known as Koch postulates. These postulates provided a clear logical and experimental framework to show that a particular microbe is the causative agent of a particular disease. While Pasteur contributed greatly to the germ theory and van Leeuwenhoek first observed microorganisms, Koch is most closely associated with proving causation in a rigorous way.

Step-by-Step Solution:
1. Van Leeuwenhoek was the first to observe microorganisms but did not prove they cause disease. 2. Louis Pasteur demonstrated that microorganisms cause fermentation and helped develop the germ theory, but the question focuses on formal proof for specific diseases. 3. Robert Koch developed Koch postulates, for example linking Bacillus anthracis to anthrax. 4. Alexander Fleming discovered penicillin, the first widely used antibiotic, and did not formulate the basic disease causation postulates. 5. Therefore, the scientist who proved that specific microorganisms cause specific diseases is Koch.

Verification / Alternative check:
Microbiology textbooks clearly credit Koch with establishing postulates for disease causation. These postulates are often listed in exam syllabi and are central to understanding infectious disease etiology.

Why Other Options Are Wrong:
van Leeuwenhoek: Important for the discovery of microscopic life but not for proving disease causation. Fleming: Known for discovering penicillin, which treats bacterial infections rather than proving their cause. Pasteur: Major contributor to germ theory and vaccination but not the author of Koch postulates.

Common Pitfalls:
Students often confuse Pasteur and Koch because both worked on germs and disease. A useful memory aid is that Koch postulates share his name, directly linking him to the formal proof that microorganisms cause specific diseases.

Final Answer:
The scientist who proved that specific microorganisms cause specific diseases through his famous postulates is Koch.