Know is the opposite of Forget. Forget is derived from Get. Get is a synonym of Fall. Fall is a type of Issue. 
Ideal is related to Theory. Theory is related to Experiment. Experiment is a type of Inquiry. Inquiry is a synonym of Research. 
Know <--Antonym--> Forget --DerivedFrom--> Get <--Synonym--> Fall --IsA--> Issue 
Ideal <--RelatedTo--> Theory <--RelatedTo--> Experiment --IsA--> Inquiry <--Synonym--> Research 