Final answer:
The liar paradox involves self-reference and a contradiction inherent in language, while the ontological argument is critiqued for the logical leap from conceptual to actual existence. They do not involve the same mistake as they are based on different types of logical reasoning.
Step-by-step explanation:
The question asks whether the derivation of the liar paradox and the ontological argument involve the same mistake. To answer this, we must first understand the nature of each argument. The liar paradox is a self-referential paradox, for instance, "This statement is false." The contradiction occurs because if the statement is true, then it must be false, and vice versa.
The ontological argument, on the other hand, is an a priori argument for the existence of God, suggesting that the notion of a supreme being (God) inherently includes existence in reality. The main criticism is the logical leap from conceptual existence to actual existence without empirical evidence. Gilbert Harman's idea of no false lemmas is relevant here; a belief cannot be based on an inference that uses false premises. Yet, this doesn't directly resolve issues in the ontological argument, which some perceive as containing a logical mistake in conflating conceptual existence with actual existence.
While both arguments lead to paradoxes or are critiqued for logical flaws, they do not share the exact same mistake. The liar paradox deals with self-reference and logical inconsistency within language, while the ontological argument presupposes existence as a property that can be deduced from conceptual understanding alone. Therefore, they involve different kinds of reasoning and logical errors.