(Note: I addressed JohnnyB because I mention links he has provided in previous posts.)
Let's see.
1. Hot fusion is known to work. Every day, everyone who is not visually impaired can see a huge hot fusion reactor up in the sky. The challenge is not to "prove" a well-known physical process, but to contain it so that it can be used as a viable energy source on earth.
2. Cold fusion has not been convincingly demonstrated, not by bona fide scientists, and certainly not by Rossi. If we are to believe that Rossi somehow stumbled upon cold fusion in his garage (and was able to recognize the process despite his lack of any scientific training), the process would be simple enough that we'd see it spontaneously occurring. A lightning strike would be sufficient to initiate the process. We have yet to see cold fusion occur under natural conditions.
3. If Rossi had a genuine process, it would be a simple matter to allow independent investigators demonstrate it without Rossi being anywhere near the demonstration. There are really only a few measurements that need to be made to demonstrate actual cold fusion. Independent investigators put a measured amount of defined (with regard to isotopic composition, etc.) starting material in. They initiate the reaction, carefully measuring all inputs/outputs of the device. They analyze the ending material and show that its isotopic composition is consistent with that expected if cold fusion were taking place. The compositions of the input and output materials should closely match the theoretical equations that anyone with a basic knowledge of chemistry and a paper and pencil can generate.
The failure of Rossi to perform any such analysis, much less to allow his eCat out of his sight in order for such tests to be done independently, is convincing evidence that such tests cannot be made. And the only reason for such tests to be impossible is that the eCat consists of nothing more than shipping containers and some other supplies picked up in various places and cobbled together to look impressive. And, even at that, Rossi doesn't do such a great job. At least some of the conmen in the past (thanks to JohnnyB for linking their stories) showed a bit of artistic flair when constructive their sham devices.
I am not so sure to say “cold fusion” is not occurring anywhere. The Pons Fleischmann experiment has been duplicated over 14,000 times, yet it is not understood, nor is it predictable and commercial. There is something happening and people are working on it. Sixty Minutes did the a show on an Israeli company that has made strides in the field.
It may come to nothing, but there needs to be more scientific work done to explain it.
1. Hot fusion is known to work.
***Then where is our hot fusion cars & jet packs?
2. Cold fusion has not been convincingly demonstrated, not by bona fide scientists, and certainly not by Rossi.
***Uh huh. So when his customer laid down €2M and put in an order for 12 more, it was not convincingly demonstrated.
3. If Rossi had a genuine process, it would be a simple matter to allow independent investigators demonstrate it without Rossi being anywhere near the demonstration.
***Sure it would be simple, if he had international patent protection. But he doesn’t, so it isn’t.
Look, hot fusion goes on INSIDE THE SUN. What you actually see for the most part is the corona. According to Widom and Larsen the process that takes place there is actually the same as what you call Cold Fusion (but it's not quite cold. In fact, it's intensely hot. Still, the way it progresses follows the same pathways they propose for LENR processes that've successfully shown the production of excess heat).
This is why you have to read the Widom-Larson paper. Also, there's a physicist at Purdue University who is looking at the exact same process from a slightly different view point and he's found he can tackle it with reference to Bose-Einstein condensate theory.
BTW, that's what the guys DOING THE WORK say is going on.
Now I'm ot a physicist and don't pretend to be one, but if you want to claim you see HOT FUSION on the Sun you gots' to show us the paper that puts forth the theory behind that process. And that's because I just named three fellows who say what you see on the Sun is NOT Hot Fusion.