Philosophy of religion

Philosophy of religion is the study of the meaning and justification of fundamental
religious claims, particularly about the nature and existence of God.

Philosophy of religion as part of metaphysics

Philosophy of religion was classically regarded as part of metaphysics,
since Aristotle, in some of whose writings were later identified by editors
as The Metaphysics, described one of the subjects of his investigation as
the investigation of first causes. For Aristotle, God was the first cause,
the Unmoved Mover. Philosophy of religion as a branch of metaphysics later
came to be called, by rationalist philosophers of the seventeenth and
eighteenth centuries, natural theology. In the twentieth century,
philosophers have adopted the name "philosophy of religion" for the subject,
and typically it is regarded as a separate field of specialization, but it
is also sometimes still treated as part of metaphysics, particularly by
Catholic philosophers.

On nearly anyone's conception, it should be clear why considerations of the
divine have been regarded as metaphysical. God, according to most
conceptions of God of the divine, would be in an important category of being
different from the rest of the universe. That is, God is typically conceived
as not having a body, and the "mind" of the divine is not typically regarded
as anything very like an ordinary human mind. Metaphysics, and in particular
ontology, is concerned with the most basic categories of existence, those
types of existence that cannot be explained as any other type of existence.
On the view of many, the very notion of God (the gods, the divine) cannot be
reduced to human concepts of mind or body; God is, on such a view, a sui
generis entity, an entity in a category all of its own.

The questions asked by the philosophy of religion

There are a lot of philosophical questions that can be asked about religious
beliefs. But there are two central questions in this field. They are:

  1. What is God, that is, what is the meaning of the word, 'God'?
  2. Do we have any good reason to think that God exists, or to think that
     God does not exist?

Still, there are other questions studied in the philosophy of religion.
What, if anything, would be good reason to believe that a miracle has
occurred? What is the relationship between faith and reason? What might it
mean for God to be exist as a trinity, that is as the "Father, Son, and Holy
Ghost" of Christian theology?

Monotheistic definitions

Traditionally philosophers of religion, at least in Europe, were interested
in finding out what the word "God" might refer to, in the sense in which it
is used by theists. Again, theism, can be defined as the view that exactly
one God exists, who is an eternally existent spirit, that exists apart from
space and time, which has created the universe out of nothing, and is
therefore all-powerful; and usually this being is also thought to be
all-knowing and all-loving. Even once the word "God" is defined in this
sense, there are still many difficult questions to be asked about what this
means. For example, what does it mean for a spirit to create anything? What
does "all-powerful" mean?