Yeah...I remember reading that quote years ago in Guitar Player, I think..
I am going to cop out and say Yes & No to that.....LOL
Tommy Tedesco, was probably one of THE biggest names in studio session work ever...at least in the guitar world. So I am going to defer a bit to someone like that, who knows a heckuva lot more than I do about that sort of stuff.
But there is two sides to the issue of course....
Fast OR Slow....You can honestly get away with playing a ton of "wrong" notes, if you set it up & resolve it in a satisfying manner for the listener. Which means that technically, you still really need to know your stuff to make that sort of thing work on a consistent basis. Kind of akin to Eddie Van Halen's comment about falling down the stairs and landing on your feet.
The key is that where as the average Joe can take a header down a couple flights of stairs & possibly get lucky and pull it off every so often...A trained stuntman has a much better chance of doing effectively on a regular basis. So too will a trained musician fare much better more often, than someone who just randomly flails away at notes & hopes for the best.
Part of the deal is, that with an incredibly seasoned player like a Tommy Tedesco or Steve Lukather who have done soooo many sessions under a great deal of pressure for soooo many years...To them it becomes almost like an autopilot mode of sorts when they peel off a fast run/lick/passage. They've had so many years of honing their craft, that they have become so innately aware of how to flow smoothly around the fretboard...that it becomes 2nd nature to them. They focus on the setup & the resolution and the rest falls into place through years and years of drilling & repetition.
The average learner out there with only a few years under their belts, does not have that level of innately programmed ability in them yet....so for them, YES...it is still very important to know what you are attempting to play. The more time you put in....The more likely that you are to land feet first at the end of a 32nd note flurry. :D
Then again on the other hand....The avg listener out there is not going to be as attuned to what is actually going on within a very fast passage like that. The typical human brain just is not trained to sort out all of that info coming at them that fast. And with guys like Tedesco & Lukather being in the biz of playing music that goes directly to the masses they are no doubt well aware of that & I would be inclined to believe that what he says is very true on that level. For the vast majority of people out there...it's not going to matter.
But again....LOL....Most of those people are not really going to be seeking out blazing guitar work in their daily listening habits. Which in turn means that the likely audience for 32nd note runs, is going to be fellow guitarists...whom as we all know all too well, rarely miss a chance to point out when something is sloppy and.....well...just plain "sucks". LOL
I personally think that the core issue is, that the faster & faster you play....The less overall value that one given note actually has on the passage. If you're going to play a slow B.B. King type passage, you'd damn well better nail every note spot on...because with fewer notes in play...each much will matter that much more to the whole. Someone like King may play only a few notes over the course of several measures & within that time frame, many phrasing nuances will come into play. There is much more information/energy going back & forth between the the fingers and each single note.
For someone like a Shawn Lane...playing some ridiculously fast 32nd note passage...the fingers are on each note for such a short time...fractions of a second...that by it's very nature, there is no possible way for the human body to impart as much info/interaction into each individiual note. So the feeling being imparted to the listener comes more from the passage as a whole, rather than a single or a few notes. With added emphasis being placed on the opening and closing notes, as Tommy Tedesco mentioned.
So yeah....Yes and No. ;)
Don