Science set down in working model (8)
I believe the answer is:
ontology
'science set' is the definition.
The answer and definition can be both related to thinking as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'down in working model' is the wordplay.
'down' becomes 'log' (I can't explain this - if you can you should believe this answer much more).
'in' means one lot of letters goes inside another.
'working' becomes 'on' (e.g. a machine is working or on).
'model' becomes 'toy' (toy can mean a miniature model).
'on'+'toy'='ontoy'
'log' inserted inside 'ontoy' is 'ONTOLOGY'.
Can you help me to learn more?
(Other definitions for ontology that I've seen before include "Branch of metaphysics that deals with the nature of existence" , "Area of metaphysics" .)