The moment I want to move my finger, a large number of neurons in my brain start sending each other small electrical impulses. These impulses travel from my brain to the rest of my body through the medulla oblongata and the spinal cord. They are then delivered to my arm, which forms only one part of my peripheral nervous system. When these small electrical impulses reach my finger, they cause the muscle cells there to contract and thereby enable my finger to move.
At the same time as these events are happening almost simultaneously, information from my eyes and my finger is being sent to the brain so that my finger will move in the way I expect it to. For example, if the path of my finger’s movement is somehow blocked, my brain can redirect it.
However, the event described above is not that simple. Starting from the neurons and continuing until we reach the muscles, every element that acts during this process displays extraordinarily complex alterations at both cellular and molecular levels.
Consider muscle cells, since they are moderately well understood. Upon arriving at the muscle cell, the electrical impulse causes the voltage-sensitive calcium channels in specific compartments within the cell to open and release calcium into the cell. You might remember from high school biology that muscle contraction is the result of two proteins (myosin and actin) sliding over each other. Normally, actins are masked by proteins known as tropomyosin. During the waiting period, therefore, the interaction between myosin and actin, which leads to contraction, cannot occur. This is why the muscle cell releases calcium, for when calcium is free in the cell, it binds to tropomyosin and enables it to move. As a result, actin is free to interact with myosin.1
After that, millions of molecules containing energy, known as ATP, bind to millions of myosin proteins, and the muscle contracts. When the contraction ends, the freed-up calcium is stored once again in specific compartments. When calcium is not present, tropomyosins again mask the actin proteins, and millions of muscle cells revert to their initial position, ready to respond to another contraction.
I realize that all of this is hard for the average reader to understand. However, the events that take place are even more complicated.
Expressions like “ATP binds to myosin” and “calcium is stored in compartments” are, in fact, simplified ways of explaining a highly complex event. Since there is a reason for everything, our cells should contain something that is performing these functions and carrying out such events. If we expand this problem to its limits, we will have to understand that each cell contains a large set of rapid and specific chemical reactions that occur constantly and yet do not interfere with one another. Based on current scientific knowledge, we can say that enzymes conduct almost all reactions in a cell, and that DNA has all the necessary information to produce enzymes. Enzymes are protein molecules that speed up and regulate all of the reactions that take place in a cell. If there were no enzymes, the reaction that a cell carries out in seconds could only be completed in thousands of years, and consequently, life as we know it would not exist. Life requires that the correct enzyme be found in the correct place and at the correct concentration.
Based on this, let’s revisit the above example. When the electric impulse reaches the muscle cell and calcium ions are released, this and every external and internal signal is conveyed to the DNA through a mechanism that we are just beginning to appreciate: signal transduction. Later, RNA is produced in those regions of the DNA that are responsible for producing the enzymes that enable the cell to give the appropriate answer (RNA helps DNA to produce enzymes). The synthesis of the enzyme is regulated at various checkpoints, such as during RNA production or RNA translocation out of the nucleus by other enzymes.2 ATPase, one of the many enzymes produced, makes it possible to use ATP, while another enzyme makes sure that the ATPases are in the correct location in the cell. Meanwhile, in order to sustain life, thousands of other enzymes conduct various reactions at the correct time and place. Therefore, when I move my finger, the number of active elements increases enormously.
Let’s look at the finer points of the cell. Using a simple calculation, in which each number is much smaller than the actual number used, if we assume that one million cells perform some kind of action from the reception of the first impulse in the brain until the time the muscle contracts, and if we calculate that one thousand reactions occur in each of these cells, this means that one billion reactions are performed for the simple action of moving a finger. One billion reactions, in just one second. And at the same time, my heart is beating, new blood cells are being produced, my eyes are sending visual information to my brain, my kidneys are filtering my blood, my lungs are exchanging old air with new, fresh air, my digestive system is supplying the necessary nutrients to my blood stream, and much, much more. Moreover, all of these are continually taking place. The fact that all of these actions are occurring, again based on a very rough and simple calculation, means that maybe one trillion reactions are occurring every second. As a result, a person might feel that it is quite possible, at any instant, for this perfect machine-the human body-to fall apart.
Realizing this, one might actually find it hard to believe that he or she is really alive. For example, I would never believe that such a machine would work if I did not have the empirical knowledge that it does work. How, for example, can I believe that I can produce one trillion reactions every moment and never confuse one with another, that it takes one billion reactions to move my finger, and that one trillion gears are working by themselves without making any mistakes?
With this idea in mind, I see the following lines in Epitomes of Light: “Also, since a building that contains every kind of artwork and riches cannot exist without having been built by someone, the existence of this universe is intimately connected with the existence of the Builder. If someone thinks carefully, it is impossible to accept one without the other.”3 Upon reading these words, I start to realize that all of these gears are not working by themselves, but rather that every second all of the trillion gears are being regulated by the One for whom nothing is difficult.
Suddenly, I remember that whenever the names of God are recited, I hear the name al-Hayy right next to al-Qayyum: God is He besides Whom there is no god; He is al-Hayy (the Ever-Living), al-Qayyum (the One Who sustains and protects all that exists) (Qur’an 2:255). Putting al-Qayyum next to “life” indicates, at least to me, that every living being is kept alive at each instant by al-Qayyum. If His control over each person’s existence were to be lost for even one second, one trillion gears would become irreversibly mixed up and the body would fall apart instantly. While thanking God for all that He has given me, I realize that I cannot thank Him enough for even one gear.