Different creatures have different builds, so they have different jobs and different goals. Animals that are built just to use things only need to use them well. But humans can also understand how to use things. If we don't use our understanding properly, we'll never reach our true purpose. God made every animal for something specific. Some are meant to be food. Others help with farming. Others give us cheese. For jobs like these, animals don't need to understand appearances or tell them apart. But God brought humans into the world to watch God and his works. We're not just watchers — we're interpreters too. That's why it's shameful for humans to start and stop where animals do. We should start where they start, but end where our nature takes us. Our nature leads to contemplation and understanding, and to living in harmony with nature. Make sure you don't die without seeing these things.
For where the constitutions of living beings are different, there also the acts and the ends are different. In those animals then whose constitution is adapted only to use, use alone is enough; but in an animal (man), which has also the power of understanding the use, unless there be the due exercise of the understanding, he will never attain his proper end. Well then God constitutes every animal, one to be eaten, another to serve for agriculture, another to supply cheese, and another for some like use; for which purposes what need is there to understand appearances and to be able to distinguish them? But God has introduced man to be a spectator of God and of his works; and not only a spectator of them, but an interpreter. For this reason it is shameful for man to begin and to end where irrational animals do; but rather he ought to begin where they begin, and to end where nature ends in us; and nature ends in contemplation and understanding, and in a way of life conformable to nature. Take care then not to die without having been spectators of these things.