I take it then that everyone who has commented so far more or less agrees with my conclusion-- that natural forces, known or unknown, while possibly not all forces, are sufficient to explain all phenomena
I take your conclusion to be true (probably), though I'm not sure what you mean by "possibly not all forces". What exceptions are you considering?
To support that conclusion, the meaning of the word 'natural', as in
'Existing in or in conformity with nature or the observable world; neither supernatural nor magical'needs to be expanded to include whatever caused the existence of the observable world. Since that hypothetical cause can never be verified, one may reasonably claim the possibility of an ultimate miracle,
the Big Bang. Associated with that, one may claim another miracle:
the entire universe continues to exist.
Alternatively, one may prefer to say "that's just the way things are". I suppose it makes no difference either way except, perhaps, in the way one feels about it.
