What Is Monotheism?

Monotheism holds that exactly one God exists, usually understood as the creator and as the only proper object of worship. It contrasts with polytheism, the belief in many gods, and with atheism, the absence of belief in any.

There are useful intermediate terms. Henotheism means worshipping one god while accepting that others exist. Monolatry means worshipping one exclusively without making claims about the others. Both describe positions that appear in the historical record and that are easy to mistake for full monotheism.

The clearest cases are the three Abrahamic traditions, alongside Sikhism and Zoroastrianism:

• •Judaism, with the declaration that God is one at the centre of daily prayer
• •Christianity, holding one God understood as a trinity of persons
• •Islam, with the absolute oneness of God, called tawhid, as its foundation
• •Sikhism, which affirms one God without form
• •Zoroastrianism, often cited as an early monotheistic tradition

Historians of religion generally see monotheism emerging gradually rather than appearing complete. Some biblical texts, read closely, seem to assume other gods exist while insisting that Israel worship only its own, which is monolatry rather than strict monotheism.

An unusual early episode occurred in Egypt under the pharaoh Akhenaten in the fourteenth century BCE, who promoted the sun disc Aten to the exclusion of other gods. The reform was abandoned after his death, and whether it influenced later traditions is debated without resolution.

Some traditions resist the categories. Hinduism contains monotheistic schools that regard the many deities as aspects of one ultimate reality, alongside genuinely polytheistic practice and philosophical positions that are neither.

Christianity's doctrine of the trinity has been questioned from outside as compromising monotheism, and Christian theologians have spent many centuries formulating it precisely as one God in three persons. Buddhism sits outside the scheme altogether, since it does not centre on a creator god at all.

The monotheism and polytheism split is a useful analytical tool but a blunt one, and scholars increasingly note that it was largely developed by monotheists describing others.

The more productive questions are usually about practice: who is worshipped, how, and with what exclusivity. Those questions tend to reveal more than sorting traditions into two boxes.

Monotheism creates a specific philosophical difficulty that polytheism largely avoids. If one God is all powerful, all knowing and entirely good, the existence of serious suffering requires explanation.

Polytheistic systems can attribute misfortune to conflict between gods or to a deity's indifference. Monotheistic traditions cannot take that route, and the resulting body of argument, called theodicy, is enormous. Proposed answers include free will, moral development through hardship, and limits on what human beings can understand. None has settled the question, and it remains the strongest standing objection to classical monotheism.

Believing that only one God exists still leaves room for very different ideas about what that God is like. Classical theism, found in mainstream Judaism, Christianity and Islam, describes a personal God who creates the world, remains distinct from it and continues to act within it, for example by answering prayer. Deism, which became influential among some European thinkers during the Enlightenment, accepts a creator but argues that this creator does not intervene after setting the universe in motion, rather like a maker who builds a clock and lets it run.

Two other positions blur the line between God and the world. Pantheism identifies God with the universe itself, so that everything that exists is, in some sense, divine. The seventeenth-century philosopher Baruch Spinoza is often cited as a key example, though his views are interpreted in various ways. Panentheism holds that the world exists within God, while God also extends beyond the world. These distinctions matter because two people who both call themselves believers in one God may still disagree deeply about creation, miracles and prayer.

Archaeology has given scholars direct clues about how belief in one God developed in ancient Israel and Judah. At Kuntillet Ajrud, a remote site in the Sinai dating to around 800 BCE, excavators found inscriptions on storage jars with blessings by Yahweh and his Asherah. Asherah was known as a goddess elsewhere in the region, and a similar phrase appears in a tomb inscription from Khirbet el-Qom near Hebron. Scholars still debate whether the word refers to a goddess paired with Yahweh or to a wooden cult object associated with worship.

Either way, the finds show that religious practice on the ground could be more varied than the later biblical texts recommend. A second source comes from Elephantine, an island in the Nile in southern Egypt. Papyri from the fifth century BCE record a Jewish garrison community with its own temple to Yaho, a form of the divine name, and some documents also mention other divine names alongside him. Evidence like this is one reason historians describe monotheism as developing over centuries, with official teaching and everyday practice not always matching.

A common assumption is that a monotheist believes in God and in nothing else beyond the natural world. In practice, all three Abrahamic traditions describe other spiritual beings. The Hebrew Bible includes angels who act as messengers, Christianity developed detailed teaching about angels and demons, and the Quran describes jinn, beings created from smokeless fire who, like humans, can choose to obey or rebel. None of this makes the traditions polytheistic, because each of these beings is understood as created by the one God, dependent on God, and never a rightful object of worship.

The real boundary therefore lies in worship, and traditions have argued about exactly where it falls. Catholic and Orthodox theology distinguish the adoration owed to God alone, called latria, from the honour given to saints, called dulia. The Second Council of Nicaea in 787 drew a similar line when it defended the veneration of icons. Many Protestant reformers judged that praying to saints blurred that line. In Islam the gravest sin is shirk, associating partners with God, and some reform movements have condemned visits to saints' shrines on those grounds, while many other Muslims regard such visits as legitimate devotion.

Belief in a single supreme god did not develop only inside religious communities. In the sixth century BCE the Greek poet and thinker Xenophanes criticised Homer and Hesiod for giving the gods human vices such as theft and adultery. He observed that Ethiopians pictured their gods as dark skinned and Thracians pictured theirs with blue eyes and red hair, and suggested that horses with hands would draw gods shaped like horses. Instead he spoke of one god, greatest among gods and men, unlike mortals in body or thought. Whether that counts as monotheism is debated, since the same line still mentions other gods.

Later Greek philosophy pushed further. Aristotle argued for an unmoved mover as the first cause of all change, and writers such as Philo of Alexandria, Augustine, Avicenna and Maimonides used ideas like this to describe the one God of scripture in philosophical terms. The word monotheism itself is surprisingly recent. It was coined in English in 1660 by the Cambridge philosopher Henry More. Henotheism came later still, from the German philosopher Friedrich Schelling, and was popularised by the scholar Max Müller for Vedic hymns that address one deity at a time as if it were supreme. Our tidy labels are early modern tools.

Monotheism is the belief in exactly one God, held most clearly by the Abrahamic traditions, and the historical record suggests it developed gradually out of positions like monolatry rather than arriving fully formed.