There are three essential components of a human act, namely,

(a)  

is the quality of being ascribed or attributed to something or someone.

(a)  

is one that does not come from a deliberate will.

(a)  

in the Nicomachean Ethics, states that "every art and inquiry, and similarly every action as well as choice, is held to aim at some good"

(a)  

is present in an act willed in itself

(a)  

is present in an act which is the foreseen result of another act directly willed

(a)  

It is possible that a human act (with indirect voluntariness) produces two effects: a good effect that is directly willed; and an evil effect that is indirectly voluntary. This is called a case of

(a)  

who formulated the doctrine or principle of double effect in his discussion of the permissibility of self-defense in the Summa Theologica

(a)