The distinction between subjectivity and objectivity is a basic idea of philosophy, particularly epistemology and metaphysics. Various understandings of this distinction have evolved through the work of philosophers over centuries. One basic distinction is:Something is subjective if it represents first-person subjective experience. If a claim is true exclusively when considering the claim from the viewpoint of a sentient being, it is subjectively true. For example, one person may consider the weather to be pleasantly warm, and another person may consider the same weather to be too hot; both views are subjective. Something is objective if it can be confirmed through observation, experimentation and intersubjective dialogue. For example, the discovery of penicillin began with an initial (subjective) observation of its antibacterial effects. This observation was subsequently investigated through rigorous experimentation, leading to objective evidence that established penicillin as an effective antibacterial agent.