How could the nature of mysticism ever be put into words? The word mysticism has its origin in the Greek mystikos, mysterious, and in the term myein, the closing of the eyes. Closing the eyes refers to switching off sense perception, which helps one attain inner divine enlightenment. At the same time it also signifies closing the mouth, since the secrets of mysticism must not be disclosed to the uninitiated, for they would not even understand its symbolic, allegorical expressions.
Mysticism is the technique of ecstasy by which one can swing across from the everyday plane of consciousness onto the other side, where the universe is experienced first-hand more fully, more comprehensively, more inwardly. This is why we may claim that mysticism is the fullest synthesis of man's ways of knowing, for beside the familiar cognitive and logical elements it also embraces the enlightenment of contemplation and of insight, discernment, the eureka experience, sudden understanding, satori.
Subjectively, mysticism is the capacity to recognise and follow intuition, the inner guidance, while objectively it is the exploration of supersensible secrets. A universally valid definition, embracing the various main fields of mysticism, is exclusive concentration on God, living meditation on the essence, and the realisation of the supernatural life. In a narrower sense, it means acts of worship, and the contact with the deity attained through the spiritual experiences that arise in their wake. If we conceive of mysticism in a more strictly religious sense, it is nothing other than coming to experience God directly, and a transforming union with God in love.
The experience of God may be indirect or direct, depending on whether man recognises the trace of the Creator's hand, His work – the holiness of nature, for instance – or meets his adored God face to face.
Alongside this inspired, soaring quality of spiritual experience, it is also important to go through the elements of mysticism one by one. Bertrand Russell regards belief in intuition as the first important criterion, as opposed to discursive, analytical knowledge. Intuition is suddenly revealed knowledge that at once becomes certainty. This method is an alternative to empirical knowing, a way to a fuller, more homogeneous grasp of the world. The persuasive power of intuition is immense, and while it is present it is almost impossible to doubt its truth, even when it seems to contradict sober calculation. At the same time, intuition seems to wane as civilisation advances. It is as if comfort and seeming security were veiling those intuitive emergency-faculties that came to man's aid in preserving existence and the species, in mortal danger, in delicate choices, under the pressure to decide, or indeed in prediction, foresight and divination. We may regard reason and intuition as the two paths of knowing, the former reaching as far as the relative, while the latter strives to reach the Absolute.
Another characteristic of mysticism is belief in the unity of the universe. According to Parmenides, reality is one and indivisible, and this way of seeing, in which unity is experienced, gave rise to pantheism in religion and to monism in philosophy.
The third mark of mysticism is the denial of the reality of time, since the threefold division of time contradicts the oneness that binds existence together. A consistent mystic lives in eternity, and for him past-present-future is an illusory separateness. The world and time, however, are not unreal but merely incidental, non-essential features of the universe.
Fourthly, mysticism professes: evil is only an appearance. From a certain point of view there is no good and there is no evil, and a moral value judgement is relevant only on relative grounds. If we suppose that there is no evil at all, then it would have to follow that there is no good either, and what remains is the bare affirmation of reality. Yet reality is, after all, good on the whole, and what is more, the universe is marked by a goodness of a higher order, for it is worthy of love and reverence – that is, holy!