For the past two days, I’ve been in London at a J.P. Morgan European investment summit, and a fascinating time it has been.

As investors, it's not so much the things we don't know that we need to be mindful of, but the things we don’t even know we don’t know. For Americans, how things really are in the rest of the world can easily fall into that category, so it’s been interesting to get some international perspective over the last couple of days.

Here are three of my key takeaways.

The big news today is that, after two consecutive quarters of declining growth, Japan has fallen into recession. The Japanese economy was down 1.6 percent in the third quarter, following a 7.3-percent decline the previous quarter.

Along with being aware of external problems, investors need to acknowledge one of the pending headwinds for the U.S. stock market: the potential for corporate profit margins to decline.

Today, I want to summarize a great analysis by Baijnath Ramraika and Prashant Trivedi, which suggests that margins can’t continue to climb.

One problem I have with satellite radio is that it makes me confront my own mortality every day. Let me explain. When a song comes on, I think, Oh, I remember that; it must have come out about five years ago. But when I look at the screen, the song is invariably from the 1990s or (in particularly bad cases) from the 1980s. Perhaps I’m not as young as I feel.

That said, a bit of perspective—which is a kinder word for age—is beneficial in the economics and investing game.

I’m currently reading Thinking, Fast and Slow by Daniel Kahneman—a great book on how we make decisions, and how we can learn to make better ones. Its assertions are shocking, and even insulting, but they’re all the more useful for it. (Look for a full review here soon.)

One of Kahneman’s points is how bad we are at remembering what we thought at a given time—and how we tend, in retrospect, to think we were much more prescient than we actually were.

I mentioned yesterday that employment numbers are much stronger than most people are giving them credit for. The one exception is wage growth, which, as a statistic, has some weaknesses.

Today, I want to talk about those weaknesses and look at some numbers that paint a rosier picture.

The October employment report released Friday offered another round of good news for workers and the economy as a whole.

For a couple years now, I’ve been emphasizing the positive direction of employment trends and noting that progress is accelerating, and it’s great to see the data showing that traction.

As we discussed yesterday, economic slowing in the rest of the world, while certainly a headwind for the U.S. economy, isn’t really something to worry about. U.S. economic data—3.5-percent growth last quarter, plus another month of more than 200,000 jobs created—seems to support that.

But unlike economics, where U.S. exposure is relatively small, our political and institutional exposure is intense. Here are some examples of problems abroad that should seriously worry us. 

Last night, I gave a talk to a group of clients about the strengthening U.S. economic recovery. Interestingly, most of the questions focused on the rest of the world and the risks we face as a result of serious economic issues elsewhere.

In my latest Market Thoughts video, I provide an update on the market’s recent drop and subsequent recovery, as well as discuss risks, the end of the Federal Reserve’s bond-buying program, and more potential good news for the market.