Agnosticism (from the Greek agnōstos meaning "unknowable") refers to the doctrine or ideology that claims knowledge is only accessible through the phenomena of experience. Based on modern scientific theory and methodology, it is a rejection of religious beliefs that claim supernatural interaction and interference with the natural world. The term "agnosticism" was coined in 1869 by T. H. Huxley, a British biologist and promoter of Darwinism, but the concept can be traced back to ancient Greek philosophy with Socrates. Agnosticism not only makes claims about what can be known, but also about what cannot be known - specifically the "spiritual" aspects of religious doctrine. Even though most forms of agnosticism assume atheism (a rejection of the existence of God), this is not universally accurate. In spite of apparent contradiction, there are forms of religious agnosticism that have varying degrees of popularity. Religious agnosticism often refers to those who claim that God exists while still maintaining the agnostic principle that the only access to knowledge is through experience. The "unknowable" is often attributed to God, but it is still unknowable. This form of agnosticism is similar to Deism. Many religious agnostics make very few doctrinal claims and tend to be more secular in ideology, whereas others participate in congregational activities but make no supernatural claims. In this, religious agnostics tend to engage religion more from an ethical and social mindset.