We say subjective to indicate that something is based on feelings
and opinions, and objective to indicate the opposite.
Why are these the same words as objective and subjective referring, in grammar, to nouns and pronouns in a sentence? Is this a
I'm looking around for the roots of the words…
The answer is not in the roots, but in philosophy and its historical development
'subjectum' does not mean 'brought under' (sort of: 'subjugated'). '-um' is neuter and means 'what...', 'jacere' means '[to] lie/lay', therefore: 'what lies underneath, what is hidden'
'subject'comes from latin 'subiectum': in ancient philosophy it was a translation of the greek 'ὑποκείμενον' (= what is under), which was used by Aristotle to indicate both the 'substance' and the 'matter' on which the 'form' is impressed. This Aristotelian distinction and terminology had currency for many centuries, down to Descartes, then Latin was superseded as a universal language. It corresponds roughly to Kant's concept of 'noumenon' 'the thing in itself/ per se': the intrinsic substantial reality as opposed to the 'object': what appears to the senses, its representation in the mind.
But Kant reversed the terms and considered 'the thing in itself' as the object and now the subject is the human mind that categorizes the 'noumena': the subject perceives and describes the object:
Kant's "categories of understanding" are descriptions of the sum of
human reasoning that can be brought to bear in attempting to
understand the world in which we exist (that is, to understand, or
attempt to understand, "things in themselves").
This is still one of the current meanings of 'subject' in spite of its etymology.
the mind, ego, or agent of whatever sort that sustains or assumes the
form of thought or consciousness That is the historical reason why
The terms of grammar are based on this distinction. Linguistics followed philosophy.
refers then both to 'the subject' of a verb/sentence and to a 'personal' interpretation of reality