The necessity of food for the support of life gives rise, probably, to a greater quantity of exertion than any other want, bodily or mental. The Supreme Being has ordained that the earth shall not produce good in great quantities till much preparatory labour and ingenuity has been exercised upon its surface. There is no conceivable connection to our comprehensions, between the seed and the plant or tree that rises from it. The Supreme Creator might, undoubtedly, raise up plants of all kinds, for the use of his creatures, without the assistance of those little bits of matter, which we call seed, or even without the assisting labour and attention of man. The processes of ploughing and clearing the ground, of collecting and sowing seeds, are not surely for the assistance of God in his creation, but are made previously necessary to the enjoyment of the blessings of life, in order to rouse man into action, and form his mind to reason.
To furnish the most unremitted excitements of this kind, and to urge man to further the gracious designs of Providence by the full cultivation of the earth, it has been ordained that population should increase much faster than food. This general law (as it has appeared in the former parts of this Essay)undoubtedly produces much partial evil, but a little reflection may, perhaps, satisfy us, that it produces a great overbalance of good. Strong excitements seem necessary to create exertion, and to direct this exertion, and form the reasoning faculty, it seems absolutely necessary, that the Supreme Being should act always according to general laws. The constancy of the laws of nature, or the certainty with which we may expect the same effects from the same causes, is the foundation of the faculty of reason. If in the ordinary course of things, the finger of God were frequently visible, or to speak more correctly, if God were frequently to change his purpose (for the finger of God is, indeed, visible in every blade of grass that we see), a general and fatal torpor of the human faculties would probably ensue;even the bodily wants of mankind would cease to stimulate them to exertion, could they not reasonably expect that if their efforts were well directed they would be crowned with success. The constancy of the laws of nature is the foundation of the industry and foresight of the husbandman, the indefatigable ingenuity of the artificer, the skilful researches of the physician and anatomist, and the watchful observation and patient investigation of the natural philosopher. To this constancy we owe all the greatest and noblest efforts of intellect. To this constancy we owe the immortal mind of a Newton.
