One of the most basic and important qualities of Deism is it's full and profound appreciation and love of life. Life is the greatest God-given gift we have. Without life, nothing is possible. With life, hope can thrive and lead and inspire us to accomplish amazing and great goals.
The life we have right now is the only life we are certain of. We have full knowledge that our next breath is not guaranteed and our life can end in an instant. This honest realization of Deism is a key to why we should love and deeply value life in general and our own lives in particular.
Unlike Christianity and Islam, Deism makes no statement about a possible afterlife as if it were a fact, when in reality it is merely a belief and not a fact. (Judaism, which Christianity and Islam both sprang out of, focuses much more on the here and now for Jews and for the Jewish state of Israel and much less on a hereafter.) Christianity and Islam both claim there is an afterlife, and in order to spend your afterlife in heaven or paradise and avoid being burned and tortured by God for eternity in hell, you must accept their ludicrous and ungodly "revealed"/hearsay religion. This twisted thinking causes countless people to actually hate their greatest gift from God, their own life. In fact, the Bible says that Jesus said (the Bible is based on hearsay, and IF Jesus really did exist as a mere human, he never wrote anything himself) we must hate our lives in order to be a disciple of his. Luke 14:26 has Jesus saying:
If any man come to me, and hate not his father, and mother, and wife, and children, and brethren, and sisters, yea, and his own life also, he cannot be my disciple.
This love of life promoted by Deism does not mean it is a selfish love of life. Many Deists risked their lives and gave up their lives for progress and their ideals. One major example are the Deists who took part in the American Revolution. They risked everything they had for the long-shot attempt to defeat and free themselves and others from the world's only super power for their ideals of freedom and liberty. And for an individual example of a Deist willing to give his life for Deism, we have the Deist Cayetano Ripoll who was executed by the Christians of the Spanish Inquisition on July 26, 1826 because he was a Deist and he was teaching other people about Deism. In both of these examples, the Deists involved had as the purpose of risking and sacrificing their lives, the great improvement of the lives of many other people and of society in general.
Realizing that the life we have is the only life we can be certain of having makes our lives more important and meaningful (provided we DO something important and meaningful with our lives).
Since there is no dogma in Deism, individual Deists are free to decide for themselves if they believe in an afterlife or not. Individual Deists hold beliefs across the spectrum on this question. Many Deists believe there is no afterlife, some believe there is an afterlife and some are not sure. That's another great quality of Deism: true freedom of thought.
Thomas Paine was a Deist who was not certain if there is an afterlife or not. In The Age of Reason, The Complete Edition he wrote his interesting ideas on the subject:
I have said, in the first part of the 'Age of Reason,' that 'I hope for happiness after this life.' This hope is comfortable to me, and I presume not to go beyond the comfortable idea of hope, with respect to a future state.
I consider myself in the hands of my Creator, and that He will dispose of me after this life consistently with His justice and goodness. I leave all these matters to Him, as my Creator and friend, and I hold it to be presumption in man to make an article of faith as to what the Creator will do with us hereafter.
I do not believe because a man and a woman make a child, that it imposes on the Creator the unavoidable obligation of keeping the being so made in eternal existence hereafter. It is in His power to do so, or not to do so, and it is not in our power to decide which He will do."
The fact that no one KNOWS for certain whether there is an afterlife or not, I believe, is a design in the Universe that allows us to love The Supreme Intelligence/God unconditionally and which allows us to focus on making a much better world in the here and now.
By being in our present state of not knowing regarding an afterlife, we must decide to love or not to love God based solely on appreciation and without any incentive based on what we can get out of it or what pain and punishment we can avoid. If we decide to love The Supreme Intelligence/God, it is for the gifts of life and reason God has given us and our loved ones. It is because of the wonderful way the Universe is designed which not only allows us to study and learn from it, thus making our own lives better and more comfortable, but also invites us to do so. The fact that we can see the stars and planets is an invitation from The Supreme Intelligence/God to think and to study and to learn based on the eternal principles science discovers in Nature and the Universe. As Albert Einstein wrote, "The most incomprehensible thing about the world is that it is comprehensible."
Deism is life and reason-based belief without fear. We strongly reject the call attributed to Jesus to fear God found at Luke 12:5 which says that Jesus said,
But I will forewarn you whom ye shall fear: Fear him, which after he hath killed hath power to cast into hell; yea, I say unto you, Fear him.
Fear is also promoted in the Bible as being the source of wisdom. Psalm 111:10 teaches that "fear of the Lord is the beginning of wisdom." This is in stark contrast with what the ancient Western philosophers taught, the Greeks and Romans, that wonder is the beginning of wisdom. Deism strongly embraces the teaching that wonder is the beginning of wisdom. Wonder is a required element of a meaningful and happy life, and a required element for progress itself.
It is Deism's deep love of life that causes it to be diametrically opposed to the anti-life teachings of the various "revealed"/hearsay religions. The sooner Deism renders them harmless, the better.