It is through reason that man justifies his belief. Rational justification strengthens his convictions. Rational argument is thus an intellectual need of every seeker. Without this he would not be able to stand firmly on his conviction. It is reason which transforms a belief system into a matter of intellectual choice. History shows that man has employed four kinds of arguments to find rational grounds for his conviction. Each of these reflects different stages in his intellectual development. Let us see how Islam stands based on these arguments.

1. Natural Argument

The first kind of argument is one based on nature. That is, on simple facts or common experiences. This has been the most commonly used since ancient times. Some examples of this kind are found in the Qur'an, one of which relates to the Prophet Abraham. It is stated as follows in the Qur'an:

Have you not considered him (Namrud) who disputed with Abraham about his Lord, because God had given him the kingdom? When Abraham said: 'My Lord is He who gives life and causes to die,' he said: 'I too give life and cause death.' Abraham said: 'So surely God causes the sun to rise from the east, then you make it rise from the west.' Thus he who disbelieved was confounded; and God does not give guidance to unjust people. (2:258)

We find another example of the argument based on natural reasoning in the Qur'an:

Thus did We show Abraham the kingdom of the heavens and the earth, so that he might become a firm believer. When night overshadowed him, he saw a star. He said: 'This is my Lord'. But when it set, he said: 'I love not those that set.' Then when he saw the moon rising, he said: 'This is my Lord.' But when it set, he said: 'Unless my Lord guide me, I shall surely be among those who go astray'. Then when he saw the sun rising, he said: 'This is my Lord. This is the greatest.' But when it set, he said: 'O my people! Surely, I am done with what you associate with God.' (6: 75-78)

Argument of this kind may appear to be simple, but they are invested with deeper meaning. For this reason, they have been engaged in as much in the past as today. So we can see that one can be convinced of Islam based on the argument of nature.

2. Philosophical Argument

The second kind of argument is that first propounded by Greek philosophers. Based on pure logic, it was so popular in the medieval ages that Jews and Christians and Muslims all incorporated it into their theological system. Commonly known as First Cause, it may be summed up as follows:

The world man observes with his senses must have been brought into being by God as the First Cause. Philosophers have argued that the observable order of causation is not self-explanatory. It can only be accounted for by the existence of a First Cause. This First Cause, however, must not be considered simply as the first in a series of successive causes, but rather as the First Cause in the sense of being the cause for the whole series of observable causes.

The Prime Mover or First Cause theory - although obviously very sound - has constantly been under attack from secular circles, and critics have raised a variety of objections. To begin with, they say that it is only guesswork, and not an undeniable fact. Some critics also object that the actions or free will of subatomic particles are uncaused; so, why not also the world as a whole? Moreover, even if all things in the world are caused, this may not be true of the world itself, because no one knows whether the whole is sufficiently like its parts to warrant such a generalization.

This is why some people think that the faith of Islam is not based on rational grounds. They say that Islamic belief can be proved only through inferential argument and not through direct argument. They assert that in Islam there is only secondary rationalism and not primary rationalism. But modern science has demolished this notion, as will be shown in the section on scientific argument. We can, therefore, see that one can be convinced of Islam based on the philosophical argument.

3. Spiritual Argument

Yet another argument is that which is based on spiritual experience. Some people, who engage in spiritual exercises and have spiritual experiences, say that when they reach the deeper levels of the human consciousness, they find an unlimited world which cannot be described in limited language. They insist that this limitless, unexplainable phenomenon is nothing but God Almighty Himself.

The critics say that even if this spiritual state is as real as is claimed by those who enter it, it is still a subjective experience; that it conveys nothing to those who have not experienced the same spiritual state.

All the above arguments are in one way or another inferential in nature and not of the direct kind. In view of this fact, the critics hold that all faiths, including Islam, have no scientific basis. They contend that Islamic theology is not based on primary rationalism, but on secondary rationalism.

However, these contentions appeared to be valid only by the end of the nineteenth century. The twentieth century has closed the chapter on all such debates. Now, according to modern developments in science, one can safely say that religious tenets can be proved on the same logical plane as the concepts of science. Now there is no difference between the two in terms of scientific reasoning.

4. Scientific Argument

Let us now see how Islam stands based on modern scientific reasoning and in the process prove the philosophical and spiritual argument further.

Religion, or faith, relates to issues such as the existence of God, something intangible and unobservable, unlike non-religious things like the sun, which has a tangible and observable existence. Therefore, it came to be held that only non-religious matters might be established by direct argument, while it is only direct or inferential argument which can be used to prove religious propositions.

It was believed, therefore, that rational argument was possible only in non-religious matters, and so far as religious matters were concerned, rational argument was not applicable at all. That is to say, that it was only in non-religious areas that primary rationalism was possible, while in religion only secondary rationalism was applicable.

In the past, arguments based on Aristotlean logic used to be applied to faith. By its very nature it was an indirect argument. Modern critics, therefore, ignored such arguments as unworthy of consideration. That is why religion was not thought worthy of being paid any attention by rational people. This state of affairs presented a challenge not only to other religions but to Islam as well.

About five hundred years ago, with the emergence of science, this state of affairs did not change. All the scientists in the wake of the Renaissance believed that matter, in fact, the entire material world was something solid which could be observed. Newton had even formed a theory that light consisted of tiny corpuscles. As such, it was possible to apply direct argument as an explanation of material things. Similarly, even after the emergence of modern science, this state of affairs prevailed. It continued to be believed that the kind of argument which is applied to apparently tangible things could not be applied in the case of religion.

But by the early twentieth century, specifically after the First World War, this mental climate changed completely. The ancient Greek philosophers believed that matter, in the last analysis, was composed of atoms. And the atom, though very tiny, was a piece of solid matter. But with the breaking of the atom in the twentieth century, all the popular scientific concepts underwent a sea change. The theories about faith and reason seemed relevant only while science was confined to the macrocosmic level. Later, when science advanced to the microcosmic level, it underwent a revolution, and along with it, the method of argument also changed.

So far, science had been based on the proposition that all the things it believed in, like the atom, could be directly explained. But when the atom, the smallest part of an element, was split, it was revealed that it was not a material entity, but just another name for unobservable waves of electrons.

This discovery demonstrated how a scientist could see only the effect of a thing and not the thing itself. For instance, the atom, after being split, produces energy which can be converted into electricity. This runs along a wire in the form of a current, yet this event is not observable even by a scientist. But when such an event produces an effect, for instance, it lights up a bulb or sets a motor in motion this effect comes under a scientist's observation. Similarly, the waves from an X-ray machine, are not observable by a scientist, but when they produce the image of a human body on a plate, then it becomes observable.

Now the question arose as to what stand a scientist must take? Should he believe only in a tangible effect or the intangible thing as well, which produced that effect? Since the scientist was bound to believe in the tangible effect, he had no choice but to believe in its intangible cause.

Here the scientist felt that direct argument could be applied to the tangible effect, but that it was not at all possible to apply direct argument to the intangible cause. The most important of all the changes brought about by this new development in the world of science was that, it was admitted in scientific circles that inferential argument was as valid as direct argument.

That is, if a cause consistently gives rise to an effect, the existence of the intangible cause will be accepted as a proven fact, just as the existence of the tangible effect is accepted because it is observable. In modern times all the concepts of science that were held to be established have been proven by this very logic.

After reaching this stage of rational argument the difference between religious argument and scientific argument ceases to exist. The problem faced earlier was that religious realities, such as the existence of God, could be proved only by inference or indirect argument. For instance, the existence of God, as a designer (cause) was presumed to exist because His design (effect) could be seen to exist. But now the same method of indirect argument has been generally held to be valid in the world of science.

There are numerous meaningful things in the universe which are brought to the knowledge of human beings, for which no explanation is possible. It has simply to be accepted that there is a meaningful Cause, that is God. The truth is that, without belief in God, the universe remains as unexplainable as the entire mechanism of light and motion is without belief in electric waves.

Thus, the option one has to take is not between the universe without God and the universe with God. Rather, the option actually is between the universe with God, or no universe at all. Since we cannot, for obvious reasons, opt for the latter proposition, we are, in fact, left with no other option except the former, that is, the universe with God.

In view of the recent advancement in scientific reasoning, a true faith has proved to be as rational as any other scientific theory. Reason and faith are now standing on the same ground. In fact, no one can legitimately reject faith as something irrational, unless one is ready to reject the rationality of scientific theories as well. For, all the modern scientific theories are accepted as proven on the basis of the same rational criterion by which a matter of faith would be equally proved true. After the river of knowledge has reached this advanced stage, there has remained no logical difference between the two. We, therefore, have to accept that faith stands on the same level of conviction as reason. So we can see that one can be convinced of Islam based on the argument of modern science as well.