at some point some ideas have to be created by some individual human who then transfers it to others, if we do not agree that the idea created by the individual human is created in their mind then we have to come up with another explanation of what they are created in. If we assume that a new idea, never before propagated creates itself we should have an explanation for how that works, which memetics does not have a current explanation for.
IMHO, this depends what you consider a "new" idea: ideas mutate and change, they are combined or applied in a different context but rarely (perhaps never) do they arise sui generis from nothing. Analogously, viruses mutate and change in their hosts, and at some point their lineage diverges enough that we declare it a "new" virus - but this is a categorization applied by an observer, and somewhat false.
Perhaps the earliest "ur ideas" were something like instinctive emotions. Even very simple creatures seek food and avoid noxious stimuli. Is hunger an idea? Maybe from hunger arose desire, and from desire arose searching, and from searching arose planning... Ad astra per fame.
> If we assume that a new idea, never before propagated creates itself we should have an explanation for how that works, which memetics does not have a current explanation for.
The same way viruses change: usually recombination, but sometimes random mutation. Yes this happens in a human mind, just like viruses change within cells. The point is to focus on ideas as self-propagating and humans as merely vessels, rather than the other way around as people usually think about them.
