Now you may be expecting this chapter to get into which of the Flashes is really the fastest, but we're actually headed into far stranger territory. My purpose here is not to contest which Flash is the fastest, but to question if Barry Allen is actually a man. Or at least, if he was actually a man from the 50s - 80s.
You see, I believe that Barry Allen, after being struck by the lightning bolt, may not have been a human at all… though he believed he was. You see, Barry's Flash comics liked to pretend to be scientifically sound, which means that they spent a great deal of time trying to explain how everything was happening - including Flash's speed.
This was before the introduction of the Speed Force, so Barry's speed was explained as 'total molecular control'. For example, Superman could run very fast, but that could be because he was very strong, and could actually push himself forward very quickly. Flash was not super-humanly strong, so a different explanation was needed - total molecular control.
I believe the original intended meaning of this concept was that Flash effectively had telekinesis over his own molecules. It looked like he was moving fast because he was pushing off of the ground, but he was actually telekinetically moving his own molecules in a parody of running.
Notably, Jay Garrick was never described as having this total molecular control - he was originally a metahuman who was simply very fast.
Now, the original iteration of Barry Allen looked a little different than he does today, and even the comics made note of how strange he was. In Wally West's early comics, he had his friends try to scientifically figure out what his deal was. They studied him and his speed for a while, and concluded that they had some idea what was going on with him, and no idea what was going on with Barry Allen.
While Wally West displayed the increased appitite we now associate with speedsters, as well as the need to sleep excessively to fuel his speed, neither of these mortal issues bothered Barry Allen. He had nigh unlimited speed, never quite reaching his full potential (until, perhaps, his death) and seemed to suffer no side effects whatsoever.
In addition to this, the 'total molecular control' began to have some… strange side effects, particularly as his series wore on. Flash could move 'spare molecules' around whenever he wanted, allowing him to hurl his molecules around wherever he wanted them. For instance, after being turned into a puppet in #133, Flash was able to move by sending his spare molecules to fill out his suit so that he regained rudimentary motion.
Flash also spent an unusual amount of time in space for a man who's power relied on running upon the ground. His aura would protect him from the vacuum and hold in a small amount of air, and he could shoot off his molecules to propel him like little rockets for motion.
Flash could do more than just auto-telekenesis, however - he could turn his molecules into super conductors, transform himself into electricity, or even, on one memorable occasion, transform into a being of anti-matter. And even that isn't all - in #176 his wife Iris was in danger of dying of some very bad dreams so Flash… broke the speed of light to run into the "Dream Dimension" where he then merged with Iris' dreams to fight off the nightmare and save her life. Science at its best.
My conclusion from this… is that none of it makes any sense. Now, perhaps the super speed and the molecular control were meant to be separate unrelated powers, however, he still has both these powers, so this doesn't really change his innate inhumanity.
My theory is that Barry Allen actually had nigh-unlimited power, and that the only thing limiting him was his own imagination. When Flash first got his powers, he didn't realize anything was different, and he wasn't even scratched by the lightning bolt. He didn't believe he would be hurt, and he visualized himself as unharmed, so he was. Then he tried to run down a taxi. All his attention was focused on catching up to the cab… so he did. By running very fast. Then he went to a diner and the waitress spilled her food. His impulsive reaction was to help catch everything… so he did.
After this, Barry believed he knew what was going on. As an avid fan of Jay Garrick's Flash comics, he already had an explanation for what was happening. He believed he was very fast, just like his childhood hero, so that's how his powers presented themselves. But as a scientist, he needed an explanation for how his powers worked, so he came up with his theory of total molecular control.
After thinking about it, he came up with more things that total molecular control ought to do, and so he was able to do those things as well.
He may even have been responsible for creating Kid Flash. Wally has Barry's exact origin story, with the lightning and the chemicals, and it happens right as Barry was reminiscing. Perhaps, subconsciously, Barry gave Wally his powers - but he only thought about making him fast, which is why Wally never had total molecular control.
We even know that Barry made other speedsters faster by being around them: in Flash v3 #24 it's mentioned that Jay Garrick always felt faster when Barry was with him, and Wally has experienced speed boosts from Barry before as well. Clearly, Barry's subconscious was impacting the people around him as well.
This would also explain all the scientifically impossible things Barry has done over the years (in one memorable occasion he spun the Trickster on his head like a top, sending him drilling through the ground until he struck oil).
The only reason Barry even looked like a human was because that's how he visualized himself: that's what he believed he was. When he died in Crisis on Infinite Earths, he even believed that he was going to die beforehand, making that another self-fulfilling prophecy.
Food for thought.
