Cat just after occupying snug offers universal theory (9)

I believe the answer is:

cosmogony

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'universal theory' is the definition.
The answer and definition can be both related to thinking as well as being singular nouns.
Maybe they are linked in a way I don't understand?

'cat just after occupying snug' is the wordplay.
'cat' becomes 'mog' (informal British term).
'just after' becomes 'on'.
'occupying' is an insertion indicator (inserted letters occupy or enter the word).
'snug' becomes 'cosy' (synonyms).
'mog'+'on'='mogon'
'mogon' placed inside 'cosy' is 'COSMOGONY'.

'offers' is the link.

Can you help me to learn more?

I've seen this clue in The Independent.

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