Just as mathematics education may be understood as progressive initiation into the distinctive language of mathematics ("square root," "quadratic equation," and so on) and moral education as initiation into the distinctive language of ethics ("ought," "virtue," "deontology"), so spirituality has its own distinctive language into which children need to be initiated if they are to grow spiritually. It is literacy-in other words proficiency in the distinctive language of the emotions, of computers, of spirituality or whatever- that empowers individuals to engage in thought, learning, and communication in these areas of life. But so little research has been done into the distinctive language of spirituality that it is not immediately clear what this phrase refers to, let alone how to initiate individuals into specifically spiritual discourses. What distinguishes the language of spirituality from other languages is not a specialist vocabulary- indeed, the words used in spiritual discourse are generally commonplace ones, like "journey," "health," "hunger," "quest" or "struggle"-but a powerful reliance on metaphor. Metaphor provides the normal way of exploring and talking about areas of life that are not open to scientific investigation through the senses. The imagination uses readily understood social or physical experiences to explore more complex or abstract ideas. People's understanding of spiritual concepts and spiritual experiences is made possible through metaphor, and it is in this sense that metaphors actually structure the way that the spiritual domain is understood.
The use of embodied experience as a metaphor for spiritual experience has a long history. As early as Plato, the physical world was described as a shadow of the spiritual. In the Jewish scriptures, God is a caring shepherd leading his sheep out of danger, and the Song of Solomon celebrates God's love for his people through an extended metaphor of erotic love. In the New Testament, the human body is "the temple of the Holy Spirit," and the Church is the bride of Christ. Metaphors drawn from embodied experience are often the only way to explain spiritual realities. Our understanding is led upward from the familiar, and the human to the divine and the spiritual. Understanding and loving God (whom we cannot see) thus begins by understanding and loving our fellow human beings (whom we can see, and who show in tangible form something of God's nature). The conceptual systems through which we understand spirituality are constructed out of metaphors, and these conceptual systems in turn structure what we perceive, what we experience and the way we define spiritual reality.
One core metaphor in the spiritual domain that finds expression in a whole array of variations is "the spiritual life is a journey." The journey may involve persevering in the face of difficulties and temptations, overcoming obstacles, following the right signposts, discarding unnecessary baggage, passing through a particular landscape, focusing on the destination, helping others along the way, and refusing to turn back. Scott Peck uses a quotation from Robert Frost as the title of his bestseller on the spiritual life, The Road Less Travelled (1978), while Bunyan's Pilgrim's Progress (1678) builds the same core metaphor into a thoroughgoing allegory of the spiritual life. The same analogy is also found in the Gospels, where Jesus warns his followers to take the narrow path that leads to life, not the broad way that leads to destruction, and in Islam, where the normal term for Islamic law, shari'ah, literally means the main road or highway. Clearly the conceptualization of life as a journey is not restricted to the spiritual domain, but where it is used in this way it brings significant enrichment to the concept. If spiritual language is primarily metaphorical, or is capable of carrying significance both literally and metaphorically at the same time, then spiritual meaning and spiritual truth must be different from other forms of meaning and truth. But this distancing of the spiritual domain from the level of ordinary literal meaning does not require us to conclude (as do Nietzsche and Derrida, for example) that the prevalence of metaphor undermines any search for timeless truth at all in relation to spirituality. Spirituality may well be an essentially contested concept, but not more so than aesthetics, and the language of spirituality may have something in common with the language of art and music. Metaphors do not only provide new insights into the spiritual life (and new insights that are thought-provoking because open to different interpretations and ways of thinking), but are the very bricks out of which the domain of the spiritual is constructed.