The doctrine of transmigration of souls, or reincarnation, is also based on a similar misunderstanding. Those who believe in this doctrine argue that children are born in different situations as a result of their actions in a past life. That is why some babies are born weak or healthy, blind or sighted, able-bodied or disabled, intelligent or unintelligent, and rich or poor. Otherwise, they ask—if there was no previous life and no record of good and bad deeds—how do we explain the difference? Could we say that God is unjust in bringing children of the same species into the world under such diverse circumstances? If not, then there is no explanation other than a previous life.
The believers in reincarnation have also failed to see the difference between the law of Shariah and law of nature, and use one law to measure everything. They have not realised that differences at birth are not related to the law of Shariah, but have to do with the law of nature. The child inherits the physical, economical and moral conditions of his parents and ancestors, which vary from family to family.
Medical science, which is based on the law of nature, has established that if parents are healthy, the children are likely to be healthy but if the parents are fragile, so shall be the children. Even physical features are inherited by children. This science is so vast and established by repeated experiments and observations that it cannot be refuted. It has also been shown that the condition of man and woman at the time of conception of a baby also deeply affects the child. In view of this, the Islamic Shariah has very wisely advised men and women to purify their hearts and minds when they try for a baby so that the child should inherit their purity of mind. In short, medical science has found that effects of the parents and ancestors are passed down to the children, and it is because of this that some children are born healthy while others are weak. Some are born normal while others have some birth defects.
There is a general law of nature, also mentioned in the Holy Quran, that everything has an impact on its surroundings (16:49). Everything in this world depends on others for its survival and everything can be influenced by other things in the universe. Thus, an offspring, which is the closest to his parents, is influenced by the good and bad traits of his parents. So the notion that babies are born with different characteristics as a result of their deeds in a previous birth is erroneous and absurd. This misunderstanding arises because people seek the cause of acts of nature in the law of Shariah.
The ideas of atheists and those who believe in reincarnation are based on the same error. Both have failed to identify the distinction between the law of nature and law of Shariah; they have sought the cause of acts of nature in the law of Shariah. As they were unable to find a reasonable explanation, one group concluded that it was all anarchy and the idea of God was baseless. The others argued that God is not unjust and would not punish anyone without reason. So, the disparity among newborn children must be rooted in their previous births, hence the doctrine of reincarnation. Had they pondered, they would have easily understood that God has ordained two sets of laws acting independently of each other and it is a grave error to seek the cause of acts of nature in the laws of Shariah.
To summarise, the righteous and the innocent sometimes suffer during natural calamities, diseases, and disasters. This is only because the law of nature is different from the law of Shariah. A good deed in conformity with Shariah, on its own, cannot protect one from the penalties incurred under the law of nature. For this, precautions prescribed in the law of nature are required. For instance, the event of drowning follows the laws of nature and a righteous person will have to learn to swim and take other precautions to save himself from drowning, just like anyone else. Just being righteous will not save him from drowning in water. Similarly, the birth of a disabled baby is an act of nature and seeking its cause in the Shariah is pointless. Here, parents need to turn to the law of nature and parents should seek the cure for their sickness, weakness, and defects, and focus on improving the environmental factors that lead to such disabilities.