We can prove similarly that an infinite series of objects is also an impossibility. In other words, infinite number as an actuality is impossible because it is a contradiction in terms. A number of things means a known number; infinite means having no known number. A series is something that has beginning, middle and end. Infinite means being all middle. We have thus proved that an actual infinite is impossible, whether as extension or number. And the Bible also alludes to the finiteness of the universe in the words of Isaiah (40, 12): "Who hath measured the waters in the hollow of his hand...," intimating that the universe is capable of being measured. We must prove next that no finite body can have an infinite power. For let the line _ae_ ------------- be a finite line having an infinite _a_ _b_ _c_ _d_ _e_ power. Divide into the several parts _ab_, _be_, _cd_, _de_, etc. If every one of the parts has an infinite power, _ab_ has an infinite power, _ac_ a greater infinite power, _ad_ a still greater, _ae_ a still greater, and so on. But this is absurd, for there cannot be anything greater than the infinite. It follows then that each of the parts has a finite power; and as the sum of finites is finite, the line _ae_ also has a finite power. All these principles we must keep in mind, for we shall by means of them prove later the existence and incorporeality of God.[235] As the concepts of physics are essential for proving the existence of God, so are the principles of psychology of importance in showing that there are intermediate beings between God and the corporeal substances of the world. These are called in the Bible angels. The philosophers call them secondary causes.