What does "moral agent" and "moral agency" mean respectively?

Question

“Agent”, OED says, could mean “an active and efficient cause, capable of producing a certain effect”; “agency” could mean “a thing or person that acts to produce a particular result”. It seems they are synonyms.

“Agent” in “moral agent”, though means simply a subject, an “actor”, can be understood in a sense as a cause of an act. Since “moral agency” is used to mean the inner dynamics of the moral agent, “agency” is to be understood as “cause” too: what makes the agent act morally?

To treat them both as meaning “cause” cannot justify them representing two things different in order. Therefore I doubt that maybe “agent” refers to the causes which are of natural kind, such as human or corporation, while “agency” can mean the inner cause that explains how the causes work as a cause.

Sorry, this may be a very immature thought, please feel free to correct me!

Answer 1

There is a straightforward terminological clarification here, and then a much richer philosophical problem beneath it.

An "agent" in this sense is someone who does things. It derives from the Latin word "ago" which means "(I) do." Romans used it as their general "doing" verb for a wide range of activities. Our word "agenda" comes from the same word, and literally means "things that ought to be done." A secret agent is just someone who does things secretly.

A "moral agent" is therefore someone (or something) capable of doing things rightly or wrongly. Typically, this is understood to mean acting with the ability to freely choose (within parameters) what to do. It sometimes also includes the idea of being aware of the concepts of rightness and wrongness, or of what actions are considered right and wrong.

"Agency" is simply the capacity to be an agent, which means the capacity to do things. We see the same relationship between the words "regent" (a monarch) and "regency" (the commission to serve as a monarch or status of being a regent). Moral agency is the capacity to act as an agent. It's something that every moral agent has by virtue of being one.

Once you get the definitions sorted out, I don't think there's anything puzzling there. However, embedded in your question is a challenging question about who or what does the causing when a person acts. Does a person cause his/her actions? Is there some sense in which his/her agency could itself be the cause? This slides us into the longstanding problem of mental causation. It's the problem of how a mind (which seems at first glance to be a non-physical thing known to us through our conscious experiences, thoughts, and feelings) could ever serve as a cause of physical things like our picking up a rock and throwing it. It's very difficult to figure out what could be doing the causing when an agent acts. Given your interest, you may want to read more about mental causation.