I want to say that something is extremely challenging for both intrinsic and extrinsic reasons – for example, doing research on something happening on Neptune (intrinsic – Neptune is harder to observe) that is also politically charged (extrinsic – the politics get in the way of objectivity but are external to the thing itself).
I can say that, of course – I just did. But what if I wanted to use 'innate' (for its innate in-bornness) rather than 'intrinsic'? What is its antiword, if it exists? Perhaps some Latin way to say 'not inborn'?
Edit: I'm really specifically into reasons here, not skills or behaviours. An acquired vs. innate skill and a learned vs. innate behaviour are all well and good, but I don't think they are as good a fit for reasons.
Best Answer
You can consider adventitious for reasons and ideas that are not innate.
It comes from from Medieval Latin adventitius "coming from abroad, extraneous," a corruption of Latin adventicius "foreign, strange, accidental," from advent- past participle stem of advenire "arrive". [etymonline]
Differences between innate and adventitious ideas from a philosophical standpoint: