Like a well-grounded argument

• Can be maintained
• Having some merit
• Logical, as a theory (7)
• Like a rational argument
• Like a good argument or theory
• Defensible
• Valid

Wiktionary Word definitions in Wiktionary
a. 1 (context of a theory, argument etc English) capable of being maintained or justified; well-founded 2 (context of a defensive structure English) capable of being defended against assault or attack; defensible

Wikipedia Word definitions in Wikipedia