Final answer:
The ethical principle expressed is the tragedy of the commons, which explains the depletion of shared resources when individuals act in their own self-interest without considering the long-term consequences.
Step-by-step explanation:
The ethical principle expressed in your rationale is the tragedy of the commons.
The tragedy of the commons is an economic theory that explains the depletion of shared resources when individuals act in their own self-interest without considering the long-term consequences. If your colleague continues to take office supplies for personal use, others may also follow suit, resulting in a significant loss to the company.
An example of the tragedy of the commons can be seen in overfishing. If each fisherman decides to catch as many fish as they can without considering sustainable practices, the fish population will decline, affecting everyone's ability to fish in the future.
To avoid the tragedy of the commons, it is important for individuals to consider the collective impact of their actions and act responsibly to preserve shared resources.