It is obvious that all created things are connected one to another by a linkage complete and perfect, even, for example, as are the members of the human body. Note how all the members and component parts of the human body are connected one to another. In the same way, all the members of this endless universe are linked one to another. The foot and the step, for example, are connected to the ear and the eye; the eye must look ahead before the step is taken. The ear must hear before the eye will carefully observe. And whatever member of the human body is deficient, produceth a deficiency in the other members. The brain is connected with the heart and stomach, the lungs are connected with all the members. So is it with the other members of the body.
And each one of these members hath its own special function. The mind force -- whether we call it pre-existent or contingent -- doth direct and co-ordinate all the members of the human body, seeing to it that each part or member duly performeth its own special function. If, however, there be some interruption in the power of the mind, all the members will fail to carry out their essential functions, deficiencies will appear in the body and the functioning of its members, and the power will prove ineffective.
Likewise, look into this endless universe: a universal power inevitably existeth, which encompasseth all, directing and regulating all the parts of this infinite creation; and were it not for this Director, the Co-ordinator, the universe would be flawed and deficient. It would be even as a madman; whereas ye can see that this endless creation carrieth out its functions in perfect order, every separate part of it performing its own task with complete reliability, nor is there any flaw to be found in all its workings. Thus it is clear that a Universal Power existeth, directing and regulating this infinite universe. Every rational mind can grasp this fact. (‘Abdu’l-Baha,’Selections from the Writings of 'Abdu'l-Bahá’; compilation ‘Nature’, prepared by the Research Department of the Universal House of Justice)