I do think that belief in a creator is reasonable. After all, life is miraculous. To imagine that everything happened coincidentally is probably just as outrageous and farfetched as to imagine that there was some kind of intelligent design behind all life.
Is it fair and sensible to accept the existence of God? If one so chooses. Because all individuals have a different sense of what is fair and sensible, or in what they believe, they can choose to accept or choose not to accept.
Belief is not fact, but if someone accepts belief as fact, if someone asserts God exists, then so be it. if someone does not accept belief as fact, if someone asserts God doesn't exist, then also, so be it.
Reason and faith are notoriously uncomfortable bedfellows, and I would have to come down on the side of those who say that they are incompatible. The existence of a deity, afterlife, divine justice, etc. can be neither proved nor disproved by evidence. I would say, though, that it's not unreasonable in the sense that we usually use the word today. In fact, there is a logic to some people's religious beliefs, as the previous post demonstrates. But reason in the strictest sense is usually connected philosophically to scientific inquiry, and inasmuch as religious beliefs are untestable, they aren't reasonable.
The idea of a creator may be reasonable to some and not others; it is an opinion and open for you to decide what you believe in.
My opinion is yes, there is a creator. While some people tend to believe that science and religion are two contradicting subjects, I beg to differ. There has to be some creator, or source of power, that has created all of the atoms in the universe. I don't believe it is simply a coincidence that the laws of nature were able to create the stars, planets, and other objects in our universe. I don't think it was a coincidence that the conditions on earth were made so that living things could exist. And I don't think it was a coincidence that certain chemical components were able to come together and actually form the beginning of life on earth, and evolve and adapt in ways become the advanced organisms we humans are today. It can't simply be by chance that all of this has happened in my mind; there has to be a greater power, some sort of creator to have had these events that have led up to life as we experience it today.
This is, of course, a matter of opinion. My own feeling is that it is reasonable, though there are many who think that it is not.
My thinking is that science can explain many things, but it can never explain where the universe itself comes from. We can believe that evolution led to the rise of human beings or that the Big Bang led to the creation of the universe. But science cannot tell us where the matter that caused the Big Bang came from. Because that sort of thing remains unexplainable through science, it is at least reasonable to believe that there is a creator god who is responsible for the existence of the universe.
For example there are many verses from the Holy Qura'an that science discovered recently but they were told by the illiterate prophet, (e.g.): the stage of the parental existence stage of the baby during pregnancy, the creation of the skies and the seas. Many informations about human body it self, advices for humans to eat certain food & to avoid others. All these informations which were mentioned in the Qura'an are logical evidences that it is impossible to consider a man such as Prophet Mohammad who was illiterate to copy them from other sources. God's choice of Prophet Mohammad as illiterate is a means by which Allah wants to tell people not to suspect the message that Prophet Mohammad has been chosen to report to people.
As Muslims we believe that Allah is exist deep down in our hearts, we don’t need any scientific proof to believe so.But concerning your question the ultimate evidence of the existence of Allah is the highly organized order universe in which everything goes according to a system. Even human body contains many secrets which tells that there is a great power that organize every thing. So those who deny the existence of God are mistaken because every thing around you tells that Allah is there. There are many things that couldn't seen but we feel their power.
For example: the wind. Our sense as human being can't see it but we feel it's power when the tree move. Human mind it self is another evidence of Allah existence. We don't see the difference between stupid & intelligent person mind, but every one's action denotes his degree of intelligence. So, if we don't see Allah that doesn't mean that Allah is not exist. Another evidence that Qura'an is the word of Allah, is that Qura'an contains many information christen, scientific , geographic , that recently some of them discovered though Qura'an was sent many years ago by Prophet Mohammad who was illiterate. How could a person who doesn't know even how to read to report incidents about events happened decades before him and predicts the happening of some events. After his death( which really happened as he described), unless if this Prophet was told these informations from Allah Almighty.
If we take your question literally then the answer is no. It is not reasonable. In other words, it is not a c;aim which is based on reason. It is a faith-based claim. Their is no proof, only faith.