The material world, is only the shell of the universe: the world of life are its inhabitants.
2. If we consider those parts of the material world which lie the nearest to us, and are therefore subject to our observations and inquiries, it is amazing to consider the infinity of animals with which it is stocked. Every part of matter is peopled: every green leaf swarms with inhabitants. There is scarce a single humour of the body of a man, or of any other animal, in which our glasses do not discover myriads of living creatures.
3. The surface of animals, is also covered with other animals, which are in the same manner the basis of other animals that live upon it: nay, we find in the most solid bodies, as in marble itself, innumerable cells and cavities, that are crowded with such imperceptible inhabitants, as are too little for the naked eye to discover. On the other hand, if we look into the more bulky parts of nature, we see the seas, lakes, and rivers teeming with numberless kinds of living creatures; we find every mountain and marsh, wilderness and wood plentifully stocked with birds and beasts, and every part of matter affording proper necessaries and conveniences for the livelihood of multitudes which, inhabit it.
4. The author of the Plurality of Worlds draws a very good argument from this consideration, for the peopling of every planet: as indeed it seems very probable, from the analogy of reason, that if no part of matter, which we are acquainted with, lies waste and useless, those great bodies; which are at such a distance from us, should not be desert and unpeopled, but rather that they should be furnished with beings adapted to their respective situations.
5. Existence is a blessing to those beings only which are endowed with perception, and is in a manner thrown away upon dead matter, any further than it is subservient to beings which are conscious of their existence. Accordingly we find, from the bodies which lie under our observation, that matter is only made as the basis and support of animals, and that there is no more of the one, than what is necessary for the existence of the other.
6. Infinite goodness is of so communicative a nature, that it seems to delight in the conferring of existence upon every degree of perceptive being. As this is a speculation, which I have often pursued with great pleasure to myself, I shall enlarge further upon it, by considering that part of the scale of beings which comes within our knowledge.
7. There are some living creatures which are raised but just above dead matter. To mention only that species of shell-fish, which are formed in the fashion of a cone, that grow to the surface of several rocks and immediately die upon their being severed from the place where they grow: there are many other creatures but one remove from these, which have no other sense besides that of feeling and taste. Others have still an additional one of hearing; others of smell; and others of sight.
3. It is wonderful, to observe, by what a gradual progress the world of life advances through a prodigious variety of species, before a creature is formed that is complete in all its senses: and even among these there is such a different degree of perfection in the sense which one animal enjoys beyond what appears in another, though the sense in different animals is distinguished by the same common denomination; it seems almost of a different nature.
10. The exuberant and overflowing; goodness of the Supreme Being, whose mercy extends to all his works, is plainly seen, as I have before hinted; from his having made so very little matter, at least what fall within our knowledge, that does not swarm with life: nor is his goodness less seen in the diversity, than in the multitude of living creatures. Had he only made one species animals, none of the rest could have enjoyed the happiness of existence; he has therefore specified in his creation every degree of life, every capacity of being.
11. The whole chasm of nature, from a plant to a man, is filled up with divers kinds of creatures, rising one over another, by such a gentle and easy ascent, that the little transitions and deviations from one species to another, are almost insensible. This intermediate space is so well husbanded and managed, that there is scarce a degree of perception which does not appear in some one part of the world of life. Is the goodness, or wisdom, of the Divine Being, more manifested in this his proceeding?