This is Imam Ghazali type of classification of Philosophical Systems. It is good idea to reproduce this material in Philosophy paper-II on question about Imam Ghazali.

The main classification of the Philosophical Systems can be considered to be that of (i) Materialists & (ii) Idealists.

Materialism accepts the real existence of the material world. According to this view, both body and mind are composed of matter.

Idealism does not accept the real existence of matter. According to this view, only real thing is the mind and the "objective" world exists only as an idea in mind.

Discussion about the existence and nature of God is also the permanent feature of both these types of philosophical systems. These two types of metaphysical philosophical systems give rise to two main types of Epistemological philosophical systems namely (i) Empiricism and (ii) Rationalism.

Empiricism is a view that all the knowledge comes from only sense experience and remains confined upto basic sensory information plus the manipulation operations performed by the mind on that basic sensory information.

According to Rationalism, mind can get direct knowledge of some basic principle of reality even in complete absence of any sense experience. The "ultra-sensory" knowledge of that "basic principle" can be used as "axiom", using the method of deductive logic, for the construction of such a philosophical system that can account for the whole reality. So in this way knowledge of whole reality can be acquired in complete absence of any sense experience because the faculty of logical analysis is considered totally independent of any sensory experience and is considered a pure mind process.

Empiricism philosophy results from the materialism philosophy and the Rationalism philosophy results from the Idealism philosophy.

In every philosophical system, the most basic priciple is the assuption about the existence or non-existence of the material world. All forms of philosophical theologies result from basic assuption of that philosophical system.

Philosophical theology is different from the religious theology. In the philosophy, first of all some assumption about the existence or non-existence of the material world is choosen. Then the nature of God is "derived" or "deduced" out of that choosen assumption.

In the religious theology on the other hand, First of all the existence and any particular nature of God is "believed". Then the nature of the "objective" world is derived out of that belief.

Works of Muslim Philosophers such as Al-Farabi, Ibn-e-Sina, Ibn-e-Rushd and even Illama Iqbal were actually very honest attempts to correlate and integrate the philosophical theologies with the religious theology. Those were basically "honest attempts" because all these Muslim Philosophers (with the exception of Ibn-e-Rushd) sincerely thoght that "truth" is only one single entity and that religion and philosophy, both are the different ways whose destination is that single truth.

The view of Ibn-e-Rushd is considered somewhat different because it is held that according to him, there are two completely independent realities viz; reality of philosophy and the reality of religion.

All the Muslim Philosophers had the view that only the philosophical interpretation of religious teachings can lead to the purest form of truth.