Apologies for taking so long.
The point I was making was related to the assertion that "viruses don't exist".
I just wanted to point out that disproving this assertion is super-easy: you just need to show a virus.
Then, once you think a second about this, you start realising that "to show a virus" might not be that simple.
Let me take a little detour.
If I want to show you a swan, I can just take any swan paddling in a lake and show it to you. I can because that swan will breed another swan like itself, and all swans look basically the same, so one can be taken as representative of the whole class.
Now the question is; does this work for viruses as well?
If I show you a specimen of the cold virus, how representative is that of all the cold viruses?
Because viruses mutate, and not all parts of a cold virus might be necessary to actually give you cold. You might have two specimens which look quite different, apart from the bits that make them give you the cold; so, functionally, the are both a cold virus, but 'morphologically' (I suppose that's not the right term) they are not.
So, both "I am not going to waste time convincing people that viruses exist" and "no virus specific for X has ever been isolated" might be true at the same time, because one uses the 'functional' aspect of a virus, and the other the 'morphological' one.
There is also the possibility that I am over-speculating and talking out of my arse.
IPB