The neoplatonic and scholastic traditions tended to treat causes as hypostatized real metaphysical principles, either inferred or simply given. Modern science in its more sophisticated statements has generally treated causes in a more heuristic way, as useful for the explanation of lawful regularity in phenomena.
I read the “causes” or “reasons why” in Aristotle as a sort of hermeneutic tools for understanding. This would encompass the kind of explanations employed by modern science, as well as much else that is helpful for understanding things in ordinary life, and for realizing our potential as animals involved with meaning and values.
Aristotle’s Metaphysics treats causes in Book V, in the context of “things said in many ways”. I will here quote the short first chapter, which introduces causes indirectly through the related concept of arché (governing principle, beginning, or as Sachs translates it, “source”):
“Source means that part of a thing from which one might first move, as of a line or a road there is a source in one direction, and another one from the opposite direction; and it means that from which each thing might best come into being, as in the case of learning, sometimes one ought to begin not from what is first and the source of the thing, but from which one might learn most easily; or it means that constituent from which something first comes into being, such as the keel of a ship or the foundation of a house, and in animals some say it is the heart, others the brain, and others whatever they happen to believe is of this sort; or it means that which is not a constituent, from which something first comes into being, and from which its motion and change naturally first begin, as a child from its father and mother, or a fight from insults; or it means that by whose choice a thing is moved or what changes changes, in the sense in which the ruling offices of cities as well as oligarchies, monarchies, and tyrannies are called sources, as are the arts, and among these the master crafts most of all. Also, that from which a thing is first known is called the source of the thing, such as the hypotheses of demonstrations.”
“Causes [aitiai] are meant in just as many ways, since all causes are sources. And what is common to all sources is to be the first thing from which something is or comes to be or is known; of these, some are present within while others are outside. For this reason nature is a source, as are elements, thinking, choice, thinghood, and that for the sake of which; for the good and the beautiful are sources of both the knowledge and the motion of many things” (Sachs translation, pp. 77-78).
What is emphasized in the notion of “source”, which Aristotle uses to provide insight into that of “cause”, is what is ultimately — or at least relatively ultimately — behind something, not that which is immediately behind it. By contrast, what I have been calling the “modern” (common-sense, not properly scientific) sense of “cause” is supposed to “operate” in an at least relatively immediate and direct (proximate) way.