Theological is derived from Theology. Theological is related to Theory. Theory is related to Experimental. 
Unable is related to Impossible. Impossible is the opposite of Necessary. Necessary is related to Water. you are likely to find Life in/at/on Water. 
Theology <--DerivedFrom-- Theological <--RelatedTo--> Theory <--RelatedTo--> Experimental 
Unable <--RelatedTo--> Impossible <--Antonym--> Necessary <--RelatedTo--> Water <--AtLocation-- Life 