“All agents act for an end” according to their nature from Thomas Aquinas on natural philosophy. There is a real human nature and real essences which define what we are. For us humans, this includes being rationale animals that are persons, responsible for our choices and acts. Our acts define who we are as a persons making us better persons or diminishing who we are. We freely choose the good for us according to what we judge with our intellect as our good. We are not always correct. Sometimes our choices are not a choice of the highest good. We are moral agents. Other animals don’t make moral choices, but animals still act for what they perceive as a good according to their nature.
Real essences exist in things. They define the whatness of a thing, how it acts and its properties.. Among human beings some are more beautiful, more intelligent, richer, poorer and contribute more to the common good of society, but all humans ar equal. The reason for this is that human beings have a real essence and nature which makes them ends in themselves. This is the basis for human dignity. No human beings can be used as an object, but humans should be treated according to their human dignity as ends in themselves. We do not have the right to take innocent human life. If we have no real basis for our human dignity other than a social contract, as John Locke proposed, then there would be no real basis in reality for our equality as human beings. We would be subject to the power of governments, dictators and each other to be used as objects, which of course is evil.
There is a hierarchy of being. Some things have more worth than others. For instance a human being has more intrinsic worth and dignity than a plant. The plant is also good and has a nature. The plants acts in its existence according to its nature. Higher intelligence in a thing is a sign of its higher worth, as we see in human beings.
We know this instinctively if we listen to our conscience through what is called the powers of the natural law. If forced to choose, we would kill the plant rather than the human being. We know this instinctively and this judgement can grow or diminish throughout our lifetime based on ideas we believe in, choices we make and actions we take form our conscience over time for better or worse. Not all human beings are the same in the perfection of their potentiality into actuality of their goodness.
I believe that Mary the Mother of God is the most perfect human being who ever lived in time. She still lives in heaven. I also believe that Christ is more perfect, but Christ is a divine person with both a human and divine nature. Christ’s existence with two natures in one divine person is the mystery of the Incarnation. Belief in this teaching of Christianity is a matter of faith which was defined at the Council of Nicea in 325 AD. Humans are capable of believing this through faith as a power of the spiritual part of their nature, the soul. The soul of human beings is the form of our bodies. We are in our soul. Our soul is not in us, but we are in our soul. The soul is the animating source of life in us. We have the power to believe and choose to act in charity through participation in God’s grace which comes from our familial relationship with God and the many ways God is present to us.
The purpose built into a thing’s nature is called the final cause of its existence. The final cause is the source of a thing’s purpose or teleology which is received in the form and act of its existence. Matter has no intelligence. It is the form of a thing that has the intelligence that makes a thing what it is. All material things are composed of this matter and form. Our existence is an act because we can cease to exist in our nature and become something else through substantial change. Who supplies the form of our substance in the act of existence? It is the First Cause of all dependent beings. the Creator. We and all other things except God receive our existence and are dependent for our existence on the First Cause who cannot stop existing. God’s essence is His existence which is fully actualized. God shares existence with us out of love, which is Who and what God is. Our ultimate purpose is to be in participative communion with God and each other in heaven.