The fact that some things are ultimate may be recognized by the synechist without abandoning his standpoint, since synechism is a normative or regulative principle, not a theory of existence.
According to Peirce, synechism flatly denies Parmenides' claim that "Being is, and non-being is nothing" and declares instead that "being is a matter of more or less, so as to merge insensibly into nothing."
Peirce argued that the view that "no experiential question can be answered with absolute certainty" (fallibilism) implies the view that "the object has an imperfect and qualified existence" and implies, furthermore, the view that there is no absolute distinction between a phenomenon and its substrate, and among various persons, and between waking and sleeping; one who takes on a role in creation's drama identifies to that extent with creation's author.
Carnal consciousness, according to Peirce's synechism, does not cease quickly upon death, and is a small part of a person, for there is also social consciousness: one's spirit really does live on in others; and there is also spiritual consciousness, which we confuse with other things, and in which one is constituted as an eternal truth "embodied by the universe as a whole": that eternal truth "as an archetypal idea can never fail; and in the world to come is destined to a special spiritual embodiment."
At the same time, I really don't know anything about it," and that mental action's dependence on the brain was an assumption warranted in science by facts until contrary facts come to light, but from the standpoint of practical interest the dependence remained open to some doubt.
Synechism is not an ultimate and absolute metaphysical doctrine; it is a regulative principle of logic, prescribing what sort of hypothesis is fit to be entertained and examined.