“‘Tattva‘ means generally the ‘ness’, the essential nature of anything, the truth of it. Here it is used in the sense of the ultimate truth. When we say that tattva is the ultimate truth, there is a definitive meaning for it.

There is a truth, tattva, for everything. The pot has pot-ness as its truth because without the pot-ness there is no pot. And the pot-ness itself does not exist without a substantive, which, for a clay pot, is clay. So does the clay have pot-ness? Clay cannot have pot-ness as its truth; it can only have clay-ness. Therefore, pot-ness is an incidental attribute to clay. Clay-ness itself is an incidental attribute because clay cannot exist without being atoms. It being so, clay-ness is an incidental attribute to atoms, and those atoms themselves have atom-ness, which are incidental attribute to particals.

As we analyse the truth of something, we keep finding that it is not the truth of that thing. And if we arrive at a truth that is not an incidental attribute, which itself is the truth, then it would be the ultimate truth.” – Swami Dayananda Saraswati, Tattvabodhah