Re: Please check in here if you're going to join the "Finding Purpose in a Godless World" discussion!
Now you have me worried. I'm usually willing to treat them as "essentially" the same. But there is a difference, of course. One's sense of purpose may be entirely private, but to say something is "meaningful" has connotations that it matters to more than just me.
So if I said "Her purpose in life is to make a million dollars in two different businesses," you would find this perfectly intelligible, while if I said, "She made a million dollars in each of two different businesses! Now that's a meaningful life," you might scratch your head as to where I was coming from.
To put it quite plainly, meaning is more intersubjective. Both have elements of intersubjectivity, relying partly on a sense that we can share the purpose or meaning of our activity and be understood, but a claim of "meaning" implies that we feel we have some right to expect others to find that the thing matters as well. Even if you say, "Nothing means as much to me as my children," you are implying that your children fill a space in your values that you would expect other people to also hold valuable, if it was them.
So I am worried because I fear that our author is going to settle for a purely private understanding of "finding purpose." That would be more than just disappointing to me - it would be distressing. Hooking our sense of purpose is, in some sense, easier than settling in on our sense of meaning. A person might find a sense of purpose in living long enough to see their great-grandchild born, or in visiting every state in the Union, or in summoning the courage to tell their mean uncle what they think of him. But none of those can be said to be meaningful, even the first. Idiosyncracy doesn't have to cut off our sense of purpose from finding meaningful things to do, but the idiosyncracy should give the purpose as an instance of some larger value that matters to people in general.
To tell the mean uncle what he really needs to hear, is meaningful. To give a blessing to our great-grandchild before we die is meaningful. To travel as a source of stories about how different places are different from each other, is meaningful.
What does meaning mean? The flattened version of meaning, with only factual implications, tells us what we are working with. The inverted yield curve, with short-term interest rates higher than long-term, tells us that the central bank is trying to slow economic growth. The reason it signifies that is that otherwise powerful economic forces will bring down the short-term rates to at least slightly less than the long-term rates. (There are minor exceptions, but it is one of the most reliable rules in economic interpretation.)
When we move into values, to say that something is meaningful is to say that it signifies something important. Now, we can posit as a matter of argument that different people find different things important. But in practice on the big things we are usually willing to argue for our sense of what matters, (some of us are almost always
willing to argue for our sense of what matters,) on the assumption that a person who sees things differently is not so different from us but has yet to get the connections, the implications, that tell why a particular benefit is one that ought to matter to people in general.
I saw on social media today a claim that Simon and Garfunkel's "Sounds of Silence" was the anthem of our generation. (Never mind that nearby there were admiring tributes to "Teach Your Children Well" and "The Times They Are a-Changin'"). If you were going to make a case that the song is meaningful, you would start getting into why it matters that "people talking without speaking" is happening, or that "the words of the prophets are written on the subway walls." Why do issues of empty noise, of words that signify nothing, capture the experience of people who lived through the 60s? And the alienation of graffiti, what did it signify? In the end you might not convince many people that it is the anthem of that generation, but the person could presumably be helped to understand why so many people found the song "meaningful."
There is a book out, from 2002, called "War Is a Force That Gives Us Meaning." Chris Hedges, the author, says that the title is only partly ironic. The thrust of the book is that the way war fascinates and causes people to set aside differences is seductive. That we seek it all too easily lest we be left with a sense of meaninglessness. Thus the irony is that the meaning can all too easily be false.