For example...
For example, when somebody is dead, he would not commonly come to life again, but the mind does not see it impossible to find one way or another to bring it into life once again, and there will be no contradiction in it. But the people, commonly believe that there is only one cause for that. So, when an extraordinary event happened they thought that an impossible event had happened! All miracles are imagined to be of the impossibles, since no other cause is thought for them.
But, on a second thought, we realize that the mind does not regard them to be impossible. In other words, people think that every event has a single exclusive cause which cannot be replaced by another cause. Consequently, they think that without that very cause it will be impossible for the event to happen. Where does a flower grow? It grows in a soil with almost a fixed temperature, together with moisture.. Then the flower's seed is sowed.
If there is no water; if the temperature is higher or lower then necessary, no flower will grow. If there is no flower - seed no flower will appear. So as far as we know, flowers grow in this way. But is there any other way of growing flowers since we have never heard in our whole life of other than this common way, we say that it is impossible.
But when we see another way of growing flowers, we realize that it is not impossible, and that it is possible to grow flowers in a way different from the common one. Even a man with a will overcoming natural forces can, to some extent, perform it, let alone Allah's Will intending to perform something not through its natural causes and common way. Here, of course, is an unknown cause, not that an effect appears without any cause. This effect has another cause which is unknown to us.
To bring the idea nearer, we give an example: There are many phenomena whose causes are still unknown to man who thought them impossible to happen. Then he discovered that they can happen through other ways. The new inventions, which were possible by using the discoveries of the covered secrets of nature, are of this category.
If somebody said, years ago, that he could talk to you from several thousand kilometers and you would hear him, you would have certainly told him that it was impossible, while now everybody knows that it is possible. The supernatural causes are also one way of the implementation of phenomena, though we do not know them or cannot get to them. But it is not that there is no such ways.