JMNT(i)
20 For you see, from [the] creation (framing; founding of order out of chaos; settling) of [the] ordered System (cosmos; universe; or: world of culture, religion and government) His invisible things (unseen [qualities and attributes]) – both His imperceptible (unobservable, but effecting-all) power, ability and capacity, as well as divinity (Godship; God-state) – are habitually seen down the line (or: are normally correspondingly perceived), being continually apprehended (grasped by the mind; mentally conceived) in the results and by the effects of things which are made or done, in order for them to be continuously defenseless (without an excuse),
21 simply because, although at one point experientially knowing God with insight, they did (or: do) not glorify (imagine; esteem; suppose; fancy; conjecture about; hold an opinion of; repute) [Him] as God, or even thank [Him] (or: give thanks in joyously expressing the goodness and well-being inherent in [His] grace and favor). And so in contrast, they were made futile (vain; fruitless; without profit; empty; useless; worthless; subject to a process of meaningless frustration; subject to exercises in futility) in their reasonings (or: thought processes; dialogues; ideas that went throughout in every direction), and their [collective] unintelligent (stupid; unable-to-put-things-together) heart was darkened (= the core of their being was made to experience an absence of light in a dim, shadowy gloom of obscurity [= ignorance]).
22 [So] continuously claiming (asserting; alleging with pretense) to be wise ones, they were made to be dull (sluggish; moronic; stupid; foolish)