|Philosophical Notions Concerning Metaphysics|
As mentioned before, the Nahj al-balaghah adopts two kinds of approach to the problems of theology. The first kind of approach calls attention to the sensible world and its phenomena as a mirror reflecting the Knowledge and Perfection of the Creator. The second approach involves purely rationalistic and philosophical reflections. The latter approach accounts for the greater part of the theological discussions of the Nahj al-balaghah. Moreover, it is the only approach adopted in regard to the discussion about the Divine Essence and Attributes.
As we know, the value of such discussions and the legitimacy of such reflections have been always questioned by those who consider them improper from the viewpoint of reason or canon, or both. In our own times, a certain group claims that this kind of analysis and inference does not agree with the spirit of Islam and that the Muslims were initiated into such kind of speculations under the influence of Greek philosophy and not as a result of any inspiration or guidance effused from the Quran.
They say that if the Muslims had adhered closely to the Quranic teachings they would not have entangled themselves with these tortuous clebates. For the same reason, they view with suspicion the authenticity of such speculations found in the Nahj al-balaghah and their ascription to Imam 'Ali ('a).
In the second and third centuries a group of people opposed such kind of discussions and questioned their legitimacy, raising doctrinal objections. They insisted that it is obligatory for Muslims to be satisfied with the literal and commonly understood meaning of the words of the Quran, and regarded every kind of inquiry into the meaning of the Quran as an innovation (bid'ah) in religion. For instance, if someone inquired about the meaning of the Quranic verse "The All-compassionate sat Himself upon the Throne " [20:5], he was confronted by the displeasure of those who regarded such questions as not only improper but distasteful. He would be told: "The exact meaning is unknown and questioning is heresy". 
During the 3rd/9th century, this group, which later came to be called Ash'arites, overwhelmed the Mu'tazilites, who considered such speculations to be within the bounds of legitimacy. This victory of the Asharites delivered a severe blow to the intellectual life of Islam. The Akhbaris, who were a Shi'i school which flourished during the period between the 10th/16th and the 14th/20th centuries-and particularly during the 10th/16th and 11th/17th centuries-followed the Asha'irah in their ideas and beliefs. They raised doctrinal objections against ratiocination. Now we shall proceed to discuss the objections raised from a rationalist point of view.
As a result of the triumph of the empirical and experimental method over the deductive approach in Europe, especially in the physical sciences, the view began to prevail that rational speculation was unreliable not only in the physical sciences but also in all scientific disciplines and that the only reliable method was that of empirical philosophy. The result of it was that tne problems of theology were viewed with doubt and suspicion, because they lay beyond the domain of experimental and empirical observation.
The past victories of the Ash'arites, on the one hand, and the amazing triumphs of the empirical method, which followed one another in quick succession, on the other hand, drove some non-Shi'ite Muslim writers to the extremes of excitement. The outcome was the eclectic opinion that from the religious (Shar'i) as well as the rational point of view the use of deductive method even in problems of theology should be discarded. From the Shar'i viewpoint,
they made the claim that according to the outlook of the Quran the only approach valid in theology was the empirical and experimental method and the study of the natural phenomena and the system of creation; the rest, they declared, is no more than an exercise in futility. They pointed out that in scores of its verses, the Quran in most unequivocal terms has invited human beings to study the phenomena of nature; it considers the keys to the secrets of the origin and workings of the universe to be concealed within nature itself. In this way they echoed, in their writings and speeches, the ideas expressed by the European proponents of empirical philosophy .
Farid al-Wajdi in his book 'Ala atlal al-madhhab al-maddi (On the Ruins of Materialism), and Sayyid Abu al-Hasan al-Nadawi, in his Madha khasira al-'alam bi-inhitat al-Muslimin ("What the World Lost Through the Decline of Muslims") and the writers belonging to the Muslim Brotherhood (Ikhwan al-Muslimin) such as Sayyid Qutb and others, have supported this view, vehemently attacking the opposite viewpoint.
Al-Nadawi, in his above-mentioned book, says:
The prophets informed men about the existence of God and His Attributes and informed them about the origin and beginning of the world and the ultimate destiny of man, putting this free information at his disposal. They relieved him of the need to understand and discuss these problems the basics of which lie beyond our reach (because these problems belong to the sphere of the supra-sensible and our knowledge and experience is limited to the physical and the sensible). But men did not value this blessing and entangled themselves in debates and speculations about these problems, and strode into the dark regions of the hidden and the unknowable. 
The same author, in another chapter of the same book, where he discusses the causes of the decline of Muslims, under the heading "The Neglect of Useful Sciences," criticizes the muslim 'ulama' in these words:
The Muslim scholars and thinkers did not give as much importance to practical and experimental sciences as they gave to debating about metaphysics, which they had learnt from Greek philosophy. The Greek metaphysics and theology is nothing more than Greek's polytheistic mythology presented in a philosophical outfit, and is no more than a series of meaningless conjectures expressed in an absurd jargon. God has exempted Muslims from debate, speculation and analysis in these matters, which are not much different from the analytic pursuits of the Alchemists. But out of ingratitude for this great blessing, the Muslims wasted their energy and genius in problems of this sort. 
Without doubt, the views of the like of Farid al-Wajd; and al-Nadawi should be regarded as a kind of return to Ash'arism, though dressed in contemporary style akin to the language of empirical philosophy.
Here, we cannot enter into a philosophic discussion about the value of philosophic reflection. In the chapters entitled "The Value of Information" and "Origin of Multiplicity in Perception" of the book The Principles and Method of Realism, we have discussed the matter in sufficient detail. Here, we shall confine ourselves to the Quranic aspect of this problem, and investigate whether the Holy Quran considers the study of nature to be the only valid method of inquiry into theological problems, or whether it allows for another approach besides the above-mentioned.
However, it is essential to point out that the disagreement between the Ash'arites and the non-Ash'arites is not about the legitimacy of the use of the Book and the Sunnah as sources in the problems of theology; rather, the disagreement concerns the manner of their utilization. According to the Ash'arites, their application should not exceed mute acceptance.
According to them, we assign the various Attributes like Unity, Omniscience, Omnipotence and the rest to God because they have been ascribed to Him by the Shar'iah, otherwise we would not know whether God is such or not, because the basic principles and essentials dealing with God are beyond our reach. Therefore, according to them, we are forced to accept God as such, but we cannot know or understand that God is such. The role of the religious texts is that they prescribe for us the way we ought to think and believe so that we may follow it in our thought and beliefs.
According to the contestants of this view, these issues are amenable to human understanding, like any other rational concept or idea. That is, there exist certain principles and essentials which if known properly enable man to understand them. The role of the religious texts lies in their capacity to inspire,
motivate, and guide human reason by putting understandable principles and essentials at its disposal. Basically servitude in intellectual matters is absurd. It is like ordering one to think in a certain fashion, and asking him to derive certain prescribed conclusions. It is like ordering someone to see a thing in a certain fashion and then asking him, "How do you see it? Is it big or small? black or white?" Servitude in thinking does not mean anything other than absence of thinking and acceptance without reflection.
In short, the question is not whether it is possible for man to go beyond the teachings of the Revelation. God be our refuge, there is nothing that lies beyond them; because that which has reached us through Revelation and the Household of the Revelation (i.e. the Ahl al-Bayt [A]) is the utmost limit of perfection concerning knowledge of the Divine. Here our debate centres upon the capacity of human thought and reason, whether it can, when supplied with the basic principles and essentials, undertake an intellectual journey through the world of theological problems  or not.
As to the invitation of the Quran to study and inquiry about the phenomena of creation, and its emphasis on nature as a means for attaining the knowledge of God and the supra-natural, it should be said that it is, indubitably, a basic principle of the Quranic teachings. It is with extraordinary insistence that the Quran asks human beings to inquire into the nature of the earth, the sky, the plants and animals, and man himself, and urges them to study them scientifically.
It is also indubitable that the Muslims did not take enough worthy steps in this direction. Perhaps the real reason behind it was Greek philosophy, which was deductive and based on pure speculation, and they used this approach even in the field of the physical sciences. Nevertheless, as the history of science bears testimony, the muslim scientists did not altogether abandon the experimental method in their studies like the Greeks. The Muslims were the pioneers of the experimental method, not the Europeans, as is commonly thought, who followed on the tracks first laid by the Muslims.