Do Christian deists celebrate Christmas and Easter?" is "yes." But to explain this answer, I would like to provide some information about the meaning of these two holidays.
Many people do not know that the "Christmas" and "Easter" holidays are based on religious traditions that are centuries older than Christianity. As the Christian movement ventured beyond Judea and into the Gentile world, the movement encountered other religious traditions which were assimilated by Christians and redefined in Christian terminology.
From human history, we know that there are two times of the year celebrated by human beings in countries north of the equator. One is in the Winter, in December, and the other is in the Spring, around March or April.
From their observation of nature in the Northern Hemisphere, human beings have recognized that the longest night of the year occurs in December. After that night, the daylight increases and time of darkness decreases. This natural phenomenon has come to symbolize the "coming of light" in various religious traditions.
Some celebrate this change from darkness to light as the Winter solstice (on December 21 or 22). In Zoroastrianism and Mithraism, the mythological god called "Mithra" was the "god of light" whose "birthday" was celebrated on December 25.
In Judaism, the holiday called "Hanukkah," or the "Feast of Lights," is observed in December for eight days. Hanukkah commemorates the Jews' victory in gaining freedom from Syria in 168 BCE and the rededicating of their temple. It is celebrated by lighting candles in the Hanukkah menorah.
In Christianity, the holiday is called "Christmas" and celebrates the "birthday" of Jesus who is called the "light of the world." The December 25th date for the "birthday" of Jesus was apparently borrowed from the "birthday" of Mithra, the "god of light" in Zoroastrianism and Mithraism.
From all the above, it is apparent that the "coming of light" has made December a special time for celebration. The increasing "light" of day that overcomes the "dark" of night is seen as a time for rejoicing and hope.
In trinitarian theology, Christmas is seen as the event in which God became "incarnated" as a human being, named Jesus, through a miraculous birth to a virgin mother. In trinitarian theology, this "virgin birth" is considered necessary so that Jesus could be born "without sin" (unlike other human beings who inherit "original sin" from "Adam") and therefore able to be an unblemished "sacrifice" to atone for the sins of humankind.
Many of the Christmas hymns reflect this trinitarian theology which Christian deists do not accept. In the hymn "Silent Night," the trinitarian theology is seen in the wording "all is calm, all is bright 'round yon virgin mother and child." In "The First Noel the Angel Did Say" the fourth verse states, "Then let us all with one accord sing praises to our heavenly Lord who made heaven and earth of naught and with His Blood mankind has bought." This wording claims that Jesus is God who created the world and who died as a blood sacrifice to pay for the sins of humankind.
Since Christian deists do not accept this trinitarian theology found in many Christmas hymns, the questions arise, "Can Christian deists celebrate Christmas?" and "What does Christmas mean to Christian deists?"
Let me approach these questions in this way. Christian deists see Jesus as a human being who discovered within himself the truth that God intends for human beings to live by love for God and love for each other. Jesus taught that this truth is known by all persons because God's "word" is sown in every human heart. The "good news" or gospel, according to Jesus, is that the "kingdom of God" becomes a reality on earth as we choose to live by love. As deists, we know this from our own experience and observation. To Christian deists, Jesus was a man who taught this truth, so we honor Jesus as a teacher of the truth.
Jesus referred to himself as the "light of the world" and he said, "he who follows me will not walk in darkness, but will have the light of life" (John 8:12). But Jesus also told his disciples, "You are the light of the world. A city set on a hill cannot be hid. Nor do men light a lamp and put it under a bushel, but on a stand, and its gives its light to all the house. Let your light so shine before men, that they may see your good works and give glory to your Father who is in heaven" (Matthew 5:14-16). Christian deists believe that Jesus taught the truth because it is confirmed by our own experience. This truth provides a light to guide us in living every day. As we live by this truth, we are a "light of the world," as Jesus was. Christian deists honor Jesus by celebrating his birthday because he was a man whose life exemplified the "light" that comes from God.
Christian deists should celebrate Christmas as human beings have long celebrated this time of year in the Northern Hemisphere of the earth--as a time of human joy and hope symbolized by the "coming of the light."
The many ways that Christians celebrate Christmas, with Christmas trees, Yule logs, candles, lights, and giving of gifts, come from many different traditions. And the story of the birth of Jesus adds a tradition of love and care amid human struggle, as Mary and Joseph overcame obstacles to provide for the baby Jesus. All these beautiful symbols help us to express joy at Christmas time.
Now, let us think about Easter. Easter is celebrated on the first Sunday after the first full moon after March 20, the nominal date of the Spring Equinox. Easter Sunday comes in March or April. The name of the holiday, "Easter," apparently comes from "Eostre" which was the name of the Great Mother Goddess of the Saxon people in Northern Europe. Eostre was a Goddess of fertility. The name of the Goddess, Eostre, comes from an ancient word "eastre" for "Spring."
Spring, of course, is a time of new life. It is a time when new plants begin to grow, and new leaves appear on trees. The "dead of Winter" ends with the rebirth of vegetation in the cycle of life. Also, it is a time when many animals give birth to their young.
In human history, the celebration of "new life" in the Spring appeared many centuries before Christianity. The cycle of life that is so evident in the Spring has inspired human beings to have hope for life beyond death.
In trinitarian Christianity, the Easter holiday was adopted as the day to commemorate the "resurrection" of Jesus. Jesus was crucified by the Romans on Friday of Passover week in the Jewish tradition. He was laid in a rock tomb on Friday before sundown and the tomb was found to be empty on the following Sunday morning. Then Jesus, who was physically wounded but alive, met secretly with his disciples for some days before Jesus disappeared.
Jesus' disciples believed that Jesus had died and was brought back to life by God. The apostle Paul claimed that belief in Jesus' "resurrection" was one of the two requirements for obtaining salvation from sin and death. Paul wrote, "If you confess with your lips that Jesus is Lord and believe in your heart that God raised him from the dead, you will be saved" (Romans 10:9).
Trinitarian Christians believe that the "resurrection" of Jesus is evidence of life after death, and Easter Sunday is used to celebrate this hope. Christian Deists believe that God's power to give life is demonstrated in the fact that we have life now. Obviously, what God has already done, God can do again. As human beings have recognized for centuries before the time of Jesus, there is a cycle of life of which we are a part. Each Spring, Christian deists celebrate "new life" and the hope it brings for the future. Christians have borrowed the name "Easter" from a tradition older than Christianity, but the basic meaning of the celebration is known naturally: God has the power to give life. "Easter" is a universal experience available to anyone who chooses to observe it.
The two "holy seasons" of the year belong to everyone. Celebrate the joy that comes from the "coming of the light" at Christmas and celebrate the hope that comes from the "new life" we see evidenced at Easter. Different religious traditions may describe these holy days in different terms, but the basic meanings are shared by all who choose to celebrate.