Changes

For example, in some senses a "[[nature]]" is the ''source'' of a thing's action, a "[[substance]]" is the source of a thing's materiality and an "[[essence]]" is the source of a thing's being.  And there are "accidental" principles that are not the source of a thing's properties but are simply able to co-exist as a source of something in the principled subject.  Likewise, there must be "non-accidental" or what might be called "[[property|propertorial]]" principles that ''are'' consequential on the existence of a thing in and of itself.

For example, in some senses a "[[nature]]" is the ''source'' of a thing's action, a "[[substance]]" is the source of a thing's materiality and an "[[essence]]" is the source of a thing's being.  And there are "accidental" principles that are not the source of a thing's properties but are simply able to co-exist as a source of something in the principled subject.  Likewise, there must be "non-accidental" or what might be called "[[property|propertorial]]" principles that ''are'' consequential on the existence of a thing in and of itself.

A "[[cause]]" is a kind of principle, but the meaning of ''principle'' can be broader than "cause" in at least two ways.  Firstly, a principle can be a "privation" in the sense of the absence of a thing understood to be present by nature.  Thomas Aquinas describes this as an "accidental principle".<ref>"[T]hough privation is an accidental principle, it does not follow that it is unnecessary for generation." Aquinas, St. Thomas (1255). ''De principiis naturae'' in Bourke, Vernon J. ed. and transl. (1960). "Principles, causes and natural generation". ''The Pocket Aquinas'' (New York, NY: Washington Square Press/Pocket Books), pp. 61-77, transl. from Pauson, J., ed. (1950). ''On the Principles of Nature'' (Fribourg [France]: Société Philosophique, 1950).</ref> An example could be the absence of a woman's eye, of which could be spoken as a principle of a prevention of a cause, like in a police report.<ref>Aristotle (''c''. 350 B.C.) ''Categories'' (Athens, GR) in Hutchins, Robert M., ed. (1952). "Categories". ''Works of Aristotle, vol. 1'' in ''Great Books of the Western World'', 2nd ed. (Chicago: Encyclopaedia Britannica, 1954), vol. 8, p. 17.</ref>

A "[[cause]]" is a kind of principle, but the meaning of ''principle'' can be broader than "cause" in at least two ways.  Firstly, a principle can be a "privation" in the sense of the absence of a thing understood to be present by nature.  Thomas Aquinas describes this as an "accidental principle".<ref>"[T]hough privation is an accidental principle, it does not follow that it is unnecessary for generation." Aquinas, St. Thomas (1255). ''De principiis naturae'' in Bourke, Vernon J. ed. and transl. (1960). "Principles, causes and natural generation". ''The Pocket Aquinas'' (New York, NY: Washington Square Press/Pocket Books), pp. 61-77, transl. from Pauson, J., ed. (1950). ''On the Principles of Nature'' (Fribourg [France]: Société Philosophique, 1950).</ref> An example could be the absence of a woman's eye, of which could be spoken as a principle of a prevention of a cause, like in a police report.<ref>Aristotle (''c''. 350 B.C.) ''Categories'' (Athens, GR) in Hutchins, Robert M., ed. (1952). "Categories". ''Works of Aristotle, vol. 1'' in ''Great Books of the Western World'', 2nd ed. (Chicago: Encyclopaedia Britannica, 1954), vol. 8, p. 17.</ref>

So there is a kind of hierarchy of the ideas of principle, cause and element.

So there is a kind of hierarchy of the ideas of principle, cause and element.

Principles can be divided along three primary types: principles of reality, moral principles and logical principles.  Principles of reality may more commonly be called "principles of nature", but since there are definitions of "nature" that might call it a kind of principle itself, its use might be better avoided.  

Principles can be divided along three primary types: principles of reality, moral principles and logical principles.  Principles of reality may more commonly be called "principles of nature", but since there are definitions of "nature" that might call it a kind of principle itself, its use might be better avoided.