Watch the Non-Diatonic Ghost Notes online guitar lesson by Andrew Ford from Motown Bass Survival Guide
Non-diatonic ghost notes were one of Jamerson's specialties. The fact that he played with flatwound strings and had that mute built in the tailpiece of his Fender basses, which was standard then, gave him the ability to use this technique to its fullest. It was all about the rhythm with these notes, and the opportunity it gives you to switch positions or facilitate otherwise difficult shifts on the fingerboard. You don't hear the note quality with them, so Jamerson was able to use them in keys like Eb, Db, Ab, etc. where the open string otherwise would have clashed.
Here's an example of this concept over a sneaky, funky 2 bar groove in Eb. This one is very syncopated, we start with an A ghost note, normally this would not work if you could hear the note, but I have to find some way to mute it, with one of my hands, with some type of foam stuffed under the strings, or a device like the one I use here which was made by Carey Nordstrand.