The whole visible world is like a book written by the finger of God.  It is created by divine power, and all human beings are figures placed in it, not to shew the free-will of man, but as a revelation and visible sign, by divine will, of God’s invisible wisdom.  But as one who only glances at an open book sees marks on it, but does not read the letters, so the wicked and sensual man, in whom the spirit of God is not, sees only the outer surface of visible beings and not their deeper parts.

German mystics wrote in the same strain; for instance, the popular Franciscan preacher, Berthold von Regensburg (1272),

    Whose sermons on fields and meadows drew many thousands of
    hearers, and moved them partly by the unusual freshness and
    vitality of his pious feeling for Nature,

in spite of many florid symbolical accessories, such as we find again in Ekkehart and other fifteenth-century mystics, and especially in Tauler, Suso, and Ruysbroek.

The northern prophetess and foundress of an Order Birgitta (1373) held that the breath of the Creator was in all visible things:  ’We feel it pervading us in her visions,’ says Hammerich,[13]

Whether by gurgling brook or snow-covered firs.  It is with us when the prophetess leads us along the ridges of the Swedish coast with their surging waves or down the shaft of a mine, or to wander in the quiet of evening through vineyards between roses and lilies, while the dew is falling and the bells ring out the Ave Maria.

Vincentius von Beauvais (1264) in his Speculum Naturae demonstrates the value of studying Nature from a religious and moral point of view; and the Carthusian general, Dionysius von Rickel (1471), in his paper On the beauty of the world and the glory of God (De venustate mundi et de pulchritudine Dei) says in Chapter xxii.:  ’All the beauty of the animal world is nothing but the reflection and out-flow of the original beauty of God,’ and gives as special examples: 

Roses, lilies, and other beautiful and fragrant flowers, shady woods, pine trees, pleasant meadows, high, mountains, springs, streams and rivers, and the broad arm of the immeasurable sea ... and above all shine the stars, completing their course in the clear sky in wonderful splendour and majestic order.

Raymundus von Sabieude, a Spaniard, who studied medicine and philosophy at Toulouse, and wrote his Theologia Naturalis in 1436, considered Nature, like Thomas Aquinas, from a mystical and scholastic point of view, as made up of living beings in a graduated scale from the lowest to the highest; and he lauded her in terms which even Pope Clement VII. thought exaggerated.  Piety in him went hand in hand with a natural philosophy like Bacon’s, and his interest in Nature was rather a matter of intellect than feeling.