Unruly pinkie

[Rocktometrist]

....and he has only ever used two fingers on the left hand? Never mind the thumb. He never used the ring finger to fret? OK @Rocktometrist you got me ! You are the JPJ authority. LMFAO.

Watched the video and you're right, he does use all 4 fingers (but only uses 2 about 90% of the time)--must have misunderstood what he was saying. I'm no JPJ authority--couldn't give one loaf about him one way or the other, to be honest. His technique is pretty unorthodox, but he obviously got the job done. Does he fret with his thumb? Who knows, but it sure would be weird, and I sure can't find any video or interview evidence that he does. At the end of the day: don't know and don't care. Bye!

 

[Impetus man]

For the record, I do not advise ANY student to fret or even mute with the thumb on a bass. Please don't do this if you don't have to. Also, please use all four fingers on your fret hand. Don't let my disagreement with @Rocktometrist distract you from using good technique.
He is dead wrong about everything he says about JPJ, who is someone I actually DO admire...and have studied, and have seen live. But we are getting away from the OP here, and good technique IS more important.