A posteriori knowledge refers to information that is gained through experience or empirical evidence. This type of knowledge is dependent on observation and experimentation, meaning it is not known prior to experiencing it. For example, knowing that water boils at 100 degrees Celsius is a result of conducting experiments and observing the phenomenon. In contrast to a priori knowledge, which is independent of experience, a posteriori knowledge relies on sensory input and real-world interactions. This concept is often discussed in the context of philosophy, particularly in the works of thinkers like Immanuel Kant, who explored the distinctions between different types of knowledge.