text: So, according to Aristotle, the form of apple exists within each apple, rather than in the world of the forms.Potentiality and actuality Concerning the nature of change (kinesis) and its causes, as he outlines in his Physics and On Generation and Corruption (319b–320a), he distinguishes coming-to-be (genesis, also translated as 'generation') from: growth and diminution, which is change in quantity; locomotion, which is change in space; and alteration, which is change in quality.Coming-to-be is a change where the substrate of the thing that has undergone the change has itself changed.In that particular change he introduces the concept of potentiality (dynamis) and actuality (entelecheia) in association with the matter and the form.Referring to potentiality, this is what a thing is capable of doing or being acted upon if the conditions are right and it is not prevented by something else.For example, the seed of a plant in the soil is potentially (dynamei) a plant, and if it is not prevented by something, it will become a plant.Potentially beings can either 'act' (poiein) or 'be acted upon' (paschein), which can be either innate or learned.For example, the eyes possess the potentiality of sight (innate – being acted upon), while the capability of playing the flute can be possessed by learning (exercise – acting).Actuality is the fulfilment of the end of the potentiality.Because the end (telos) is the principle of every change, and potentiality exists for the sake of the end, actuality, accordingly, is the end.Referring then to the previous example, it can be said that an actuality is when a plant does one of the activities that plants do.In summary, the matter used to make a house has potentiality to be a house and both the activity of building and the form of the final house are actualities, which is also a final cause or end.