Verification of truth — necessary condition: A disease always has what necessary element?

Introduction / Context:
The question targets the logically necessary condition for the existence of a disease. Medical philosophy recognizes that every disease state has an etiology (cause), even if unknown.

Given Data / Assumptions:

• “Disease” encompasses infectious, genetic, metabolic, autoimmune, degenerative, etc.
• We seek what must exist for a disease to occur, not what often accompanies it.

Concept / Approach:
Some diseases are incurable (so “cure” is not universal). Treatment (“medicine”) is not always present. Not all diseases are caused by “germs” (pathogens); many are non-infectious. However, every disease has some cause (etiology), whether microbial, genetic mutation, deficiency, trauma, or multifactorial.

Step-by-Step Solution:

Verification / Alternative check:
Consider scurvy (deficiency of vitamin C), sickle cell disease (genetic), and influenza (viral). Each has a cause, but not necessarily a cure/medicine at all times, and not all involve germs.

Why Other Options Are Wrong:

• Cure: Not universal.
• Medicine: Not necessary for the disease to exist.
• Germs: Only for infectious etiologies.
• None of these: Incorrect; “Cause” is necessary.

Common Pitfalls:

• Equating “disease” with only infectious disease.

Final Answer:

Cause