THING IN ITSELF
In the above-mentioned translation of the Madhyānta-Vibhanga T. Stcherbatsky chose “thing in itself” as a rendering for the mainly mahāyānistic word svabhāva , a Sanskritic word which he further understood as “suchness”.
Nāgārjuna dedicated an entire chapter to this svabhāva of which the first verse runs:
“Na sambhavah svabhāvasya yuktah pratyaya-hetubbih, / hetu-pratyaya-sambhūtah svabhāvah krtako bhavet.” (Mūla Madhyamika kārikā. ch. 15)
It is not proper to speak of SELF-NATURE (SVABHĀVA) as a result of causes and conditions /
Were svabhāva a result of causes and conditions it would be something made (and svabhāva is not-made, is not destructible, it is, in the ultimate sense, not, at least not comprehensible by the senses).
Therefore we understand why Stcherbatsky chose “thing-in-itself”.
But since “thing-in-itself” is so heavily laden with 20th Cent. philosophical terminology there is the possibility of misrepresenting the meaning of the word.
Svabhāva has in the past been one of the concepts on which some later mahāyānistic traditions imputed the notion that there should be “thingness”, “somethingness”, sometimes called “seeds of existence”. Throughout the 20th Cent. these traditions nearly all disappeared, the Tibetan Jonang-tradition seems to be one of the last schools that holds on to the old interpretation. Confronted with scientific evidence which says that not matter but energy is the ultimate building block in the universe, svabhāva as “thingness”, “seed” can no longer be maintained.