Is it not human thinking illogical?

The premise your argument stems from is illogical.If a man can be logical to his creator only,then man can be illogical to creator only.

Logic broadly means:1)the science that investigates the principles governing correct or reliable inference;2) a particular method of reasoning or argumentation;and,3)reason or sound judgement.

Even before computers were invented and man in the very early stage of social development  learnt counting,two and two were four,not less not more.Action of a man is either governed by logic or sentiments.Those whose actions are governed  by logic are called rational,and those whose actions are government by sentiments are called sentimental.In between are crooks aka politicians,who are governed by selfishness.And IMO selfishness falls in the category of wickedness,the governing philosphy of neo-cons.

Logical thinking,arguments,approach ect.all are in relation of man to man.Once you bring in the God,logic ceases to have any meaning,let alone impact.Render unto God,what is God's;not Ceaser's.

Thank you Vand and t k Kidwai! Actually this is an issue and my conclusion may be misleading It is clear, however, that computers think logically and the result known in advance whatever complex the process or the data fed may be. Example, scientific computation.

But one cannot logically reduce what the man is thinking and what the result will be. Even it is difficult for the thinker himself know that his thinking is logical as the movement of the thinking changes at less than nano sconds. Human mind is highly complex and delicate and is difficult to assume that human mind thinks logically.One can not predetermine what one thinks using reduction or sensitivity analysis.

If man was able to know what somebody is thinking and what the result of the thinking will be, man could manuevre man and that is bad. So, man's illogical thinking is good for man himself.

Something is logical to its creator. Man cannot be logical to man as man is not the creator of man. 

I disagree, every human being was created by man more accurately by a man and a woman. Therefore, by your premise, a parent can be logical where a child cannot, at least until the child has children of their own.
Parents, by raising their children,  are effectively programing their children. This, combined with the expression of the parent's DNA creates an ability within the parents to logically predict the actions of their children.
Being a father, I can say there is truth to my statements. However, without having every scrap of information or data niether a parent nor a super computer can acuratly predict anything.  

Hi Utilaeastwind, Thank you for your comment!

If you are not religious, your comment is logical. But as a religious, man does not create man; man and woman are simply operators of what is created by God just as a computer operator is simply operating by what is invented (the computer). I think so! Creator of man is only God

Brains do what computers do.  They are designed to think & therein lies our collective problem.  We think too much, we think incorrectly & we think everything that flits through our heads is VERY important.  The trouble is not in HOW we think--how we live our lives is WHAT we think that causes us to live as we do, good results or bad.