A phenomenon , sometimes spelled phaenomenon, is an observable event. The term came into its modern philosophical usage through Immanuel Kant, who contrasted it with the noumenon, which cannot be directly observed. Kant was heavily influenced by Gottfried Wilhelm Leibniz in this part of his philosophy, in which phenomenon and noumenon serve as interrelated technical terms. Far predating this, the ancient Greek Pyrrhonist philosopher Sextus Empiricus also used phenomenon and noumenon as interrelated technical terms.
The combustion of a match is an observable occurrence, or event, and therefore a phenomenon.
A comparison between a candle flame on Earth (left) and in a microgravity environment, such as that found on the International Space Station (right). The same burning phenomenon is observed, but different flame shape and colouring phenomena are also observed.
Cloud chamber phenomena. Scientists use phenomena to refine some hypotheses and sometimes to disprove a theory. See also animated version.
In philosophy and specifically metaphysics, the theory of Forms, theory of Ideas, Platonic idealism, or Platonic realism is a theory widely credited to the Classical Greek philosopher Plato. The theory suggests that the physical world is not as real or true as "Forms". According to this theory, Forms—conventionally capitalized and also commonly translated as "Ideas"—are the non-physical, timeless, absolute, and unchangeable essences of all things, of which objects and matter in the physical world are merely imitations. Plato speaks of these entities only through the characters in his dialogues who sometimes suggest that these Forms are the only objects of study that can provide knowledge.
The central image from Raphael's The School of Athens (1509–1511), depicting Plato (left) and Aristotle (right). Plato is depicted pointing upwards, in reference to his belief in the higher Forms, while Aristotle disagrees and gestures downwards to the here-and-now, in reference to his belief in empiricism.
