You seem not to apprehend, replied Philo, that I argue with cleanthes in his own way; and, by showing him the dangerous consequences of his tenets, hope at last to reduce him to our opinion.  But what sticks most with you, I observe, is the representation which cleanthes has made of the argument a posteriori; and finding that that argument is likely to escape your hold and vanish into air, you think it so disguised, that you can scarcely believe it to be set in its true light.  Now, however much I may dissent, in other respects, from the dangerous principles of cleanthes, I must allow that he has fairly represented that argument; and I shall endeavour so to state the matter to you, that you will entertain no further scruples with regard to it.

Were a man to abstract from every thing which he knows or has seen, he would be altogether incapable, merely from his own ideas, to determine what kind of scene the universe must be, or to give the preference to one state or situation of things above another.  For as nothing which he clearly conceives could be esteemed impossible or implying a contradiction, every chimera of his fancy would be upon an equal footing; nor could he assign any just reason why he adheres to one idea or system, and rejects the others which are equally possible.

Again; after he opens his eyes, and contemplates the world as it really is, it would be impossible for him at first to assign the cause of any one event, much less of the whole of things, or of the universe.  He might set his fancy a rambling; and she might bring him in an infinite variety of reports and representations.  These would all be possible; but being all equally possible, he would never of himself give a satisfactory account for his preferring one of them to the rest.  Experience alone can point out to him the true cause of any phenomenon.

Now, according to this method of reasoning, DEMEA, it follows, (and is, indeed, tacitly allowed by cleanthes himself,) that order, arrangement, or the adjustment of final causes, is not of itself any proof of design; but only so far as it has been experienced to proceed from that principle.  For aught we can know a priori, matter may contain the source or spring of order originally within itself, as well as mind does; and there is no more difficulty in conceiving, that the several elements, from an internal unknown cause, may fall into the most exquisite arrangement, than to conceive that their ideas, in the great universal mind, from a like internal unknown cause, fall into that arrangement.  The equal possibility of both these suppositions is allowed.  But, by experience, we find, (according to cleanthes), that there is a difference between them.  Throw several pieces of steel together, without shape or form; they will never arrange themselves so as to compose a watch.  Stone, and mortar, and wood, without an architect, never erect a house.  But the ideas in a human mind, we see, by an unknown, inexplicable economy, arrange themselves so as to form the plan of a watch or house.  Experience, therefore, proves, that there is an original principle of order in mind, not in matter.  From similar effects we infer similar causes.  The adjustment of means to ends is alike in the universe, as in a machine of human contrivance.  The causes, therefore, must be resembling.