Classical theism in the context of "Philo"

Theism is broadly defined as the belief in the existence of at least one deity. In common parlance, or when contrasted with deism, the term often describes the philosophical conception of God that is found in classical theism—or the conception found in monotheism—or gods found in polytheistic religions—or a belief in God or gods without the rejection of revelation, as is characteristic of deism.

Non-theism and atheism is commonly understood as non-acceptance or outright rejection of theism in the broadest sense of the term (i.e., non-acceptance or rejection of belief in God or gods). Related (but separate) is the claim that the existence of any deity is unknown or unknowable; a stance known as agnosticism. Agnostic theism is a personal belief in one or more deities along with acceptance that the existence or non-existence of the deity or deities is fundamentally unknowable.

Conceptions of God in classical theist, monotheist, pantheist, and panentheist traditions – or of the supreme deity in henotheistic religions – can extend to various levels of abstraction:

• as a powerful, personal, supernatural being, or as the deification of an esoteric, mystical or philosophical entity or category;
• as the "Ultimate", the summum bonum, the "Absolute Infinite", the "Transcendent", or Existence or Being itself;
• as the ground of being, the monistic substrate, that which we cannot understand; and so on.

The first recordings that survive of monotheistic conceptions of God, borne out of henotheism and (mostly in Eastern religions) monism, are from the Hellenistic period. Of the many objects and entities that religions and other belief systems across the ages have labeled as divine, the one criterion they share is their acknowledgment as divine by a group or groups of human beings.

In the philosophy of religion, a cosmological argument is an argument for the existence of God based upon observational and factual statements concerning the universe (or some general category of its natural contents) typically in the context of causation, change, contingency or finitude. In referring to reason and observation alone for its premises, and precluding revelation, this category of argument falls within the domain of natural theology. A cosmological argument can also sometimes be referred to as an argument from universal causation, an argument from first cause, the causal argument or the prime mover argument.

The concept of causation is a principal underpinning idea in all cosmological arguments, particularly in affirming the necessity for a First Cause. The latter is typically determined in philosophical analysis to be God, as identified within classical conceptions of theism.

In classical theism, the doctrine of divine simplicity says that God is simple (without parts), in any manner whatsoever, including that his essence is identical with his existence.