I haved been enjoying Uchiyama's Opening The Hand of Thought, but keep coming back to a concept that I am struggling to understand and was hoping to get your perspectives.

In it he discusses the concept of past, present and future. Such that all three only exist in the present. I am on board so far.

However, he also states that we must live fully in the present and uses a story of a man who, dwelling on an earlier argument with his wife, gets into a car accident. Alluding to the idea that the man wasn't "fully in the present". This is where I have a hard time. How can I be anywhere but here, now? If I am dwelling on an argument from earlier in the day, am I still not here? Does that argument not fully exist now?

I had thought that maybe this was a(n) (over)simplification to bring the reader to focus their attention on things that they can change/address. But even so, it still seemed to throw me a curve.

Thanks for any perspectives.

Gassho,
Shawn