In this way, it has a consistency since, not measuring itself against fluctuating essences such as physics, biology, psychology, and the other sciences; it asserts that existence can be gauged only by the human's reaction and response to his own existence. And that each human has to work out for himself how to live his life (Flynn, 2006).
On the other hand, existentialism can be inconsistent since, history seems to indicate that it has often followed the fashion of the moment and country. There have been times when existentialism has been more Christian (such as with Kierkegaard) and times when it was not only atheistic but contra- religious too (e.g. Nietzsche). These moods seem to correspond with the religious mood of the moment. 'Authenticity' it seems has been defined by the social, historical, and political aspects of the country and moment. In that way, existentialism could become Christian (Kierkegaard or Marcel), Marxist (Sartre), Liberal (Camus), and bourgeoisie (Baudelaire).
Pantheism is ancient and can be found, in some form, predating Spinoza in the Kabbalah. It suggests that God is inherent and apart of the cosmos; or, in other words, that God can utterly not be disassociated from the cosmos. That all is God. That there is nothing outside of God (Harrison, 2004).
This simple view seems to possess greater consistency than any of the previously mentioned beliefs since it is, by its nature, impossible to test scientifically. History shows too that some form of pantheism has existed a long time.
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It is also subjected to subjective bias to either accept or renounce it clouding the issue. Given this situation, pantheism, too, has proved to possess a certain amount of inconsistency depending on age, country, and other factors for its current rendition.
In short, all four ideologies Biblical, naturalism, existentialism, pantheism possesses consistencies and inconsistencies depending on the level of their physicality and metaphysically. Apparently, the more physical (or natural) their substance, the more open they are to disproval and the more likely they are to change. On the other hand, differences of age and geography also cause differences in interpretation and, therefore, inconsistency, of the material.
Characteristics, too, vary with the more spiritual beliefs, such as the Bible and existentialism promoting moral and ethical values (or lack of them). Pantheism may be an exception here. The 'harder' the ideology, however, the more morals and ethics are excluded from it. Science (or naturalism) is an instance of this.
Sources
Flynn, T., 2006. Existentialism: A Very Short Introduction, Oxford: Oxford University Press.
Harrison, P., 2004, Elements of Pantheism; Religious reverence of nature and the universe, Coral Springs, Florida: Llumina Press, 2nd edition.
Kuhn, T (1962) the Structure of Scientific Revolutions 3rd ed. Chicago, IL: University of Chicago Press
