Yes, DIALECTICS is a Scrabble word!

Letter values in Scrabble US: D 2, I 1, A 1, L 1, E 1, C 3, T 1, I 1, C 3, S 1.

Is it a valid word?

DIALECTICS is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

a rationale for dialectical materialism based on change through the conflict of opposing forces
any formal system of reasoning that arrives at the truth by the exchange of logical arguments
a contradiction of ideas that serves as the determining factor in their interaction