Heidegger's fundamental ontology is the philosophical basis of Gadamer's philosophical hermeneutics. The Heidegger's Method in Fundamental Philosophy and consequently the Gadamer's Method in Philosophical Hermeneutics -in their own words – is only existential phenomenology. Hence in philosophical hermeneutics concepts such as truth, existence, understanding, meaning, world, etc. are redefined with a phenomenological approach, and for this reason The use of these words in this hermeneutics and philosophy is quite different from their use in other hermeneutics and philosophies whose method is not phenomenological. But existential phenomenology has some fundamental criticisms of it that those criticisms cause both Heidegger's fundamental ontology and Gadamer's philosophical hermeneutics to be in serious crisis. Because phenomenology was created from the ground up to solve the corresponding of the object and the mind, but in fact failed in this solution and by the redefinitions of the fundamental concepts only wiped out the problem, as a result, it cannot provide a suitable starting point for philosophical hermeneutics. Secondly, phenomenology because it is ultimately Person-based and sphere of its influence is only about the appearances that are made for the interpreter, It leads to relativism and even idealism.