Initial Observation

An initial observation is that antibiotic drugs kill cells.

Preliminary Conditions

There are two theories posed to explain how antibiotics kill cells:

A₁: Targeted Action. The drugs target specific molecules that are important to the cell. When those important molecules are destroyed the cell dies.
A₂: Superoxide Theory. The drugs disrupt the normal functioning of the cell causing production of reactive oxygen-based radicals that kill the cell.

Assume these theories have merit, satisfying at least half of the criteria for a scientific theory (it will be required to show this starting with the next set of examples). Also, each of the theories could explain the initial observation (as described above).

Data

D₁: Penicillin kills by specifically attacking cell walls.
D₂: Kanamyrin kills by specifically attacking protein assembly.
D₃: Ciprofloxacin kills by specifically attacking DNA.
D₄: Disruption of DNA by guinolones initiates responses to fix the DNA which creates superoxides and interferes with iron regulation.
D₅: Kananycin and penicillin/ampicillin triggered a flare of fluorescence, indicating a cascade of damage similar to quindones.
D₆: Using antibiotics increased the activity of a coenzyme responsible for energy production.
D₇: Antibiotics engage genes that control protein and DNA repair.
D₈: Mutant bacteria with no functional SOS response were more vulnerable to the antibiotics.
D₉: Imlay couldn't detect a boost in free iron.
D₁₀: Drugs are still lethal without oxygen.
D₁₁: Leprosy drugs spark the formation of reactive oxygen.
D₁₂: Reactive oxygen can annihilate tuberculosis-causing microbes.

Evaluation Chart

	Targeted Action	Superoxide
D1	yes	no
D2	yes	no
D3	yes	no
D4	no	yes
D5	no	yes
D6	no	yes
D7	no	yes
D8	yes	no
D9	yes	no
D10	yes	no
D11	no	yes
D12	no	yes

Result

From this data (Targeted Action - 6, Superoxide - 6), it would seem that we need more data to decide which is the best theory!