The text below is from the Christian M. Nebehay's book “Gustav Klimt. From drawing to painting”, 2007, pp. 68-69, 78:
Philosophy was thus described in the seventh Secession exhibition (8 March to 6 June 1900), where it was seen by 35,000 visitors:
“No. 22 Philosophy. One of the five allegorical paintings for the ceiling of the University's Great Hall (commissioned by the Ministry of Culture and Education). Left-hand group: Birth, Fertile Life, Death. Right: the Globe, the Enigma of the World. Surging from the depths, an illuminated apparition: Knowledge. The painting is on show until the end of March, after which it will be sent to the world exhibition in Paris.”
The catalogue was printed in two versions. In the second this page was reset and unnumbered, Philisophy already having been sent to Paris.
No colour photographs were made of the three University paintings, except for a detail of Medicine. For inexplicable reasons the paintings were put away too soon during the Second World War and stored, not with the contents of the Kunsthistoriches Museum in the salt mines of Bad Ausseem, but in Schloss Immendorf in the northern part of Lower Austria. Why colour photographs were not made before their storage remains a mystery [At the time there were 'Agfa Colour Films' for the Leica and other 35mm cameras].
It seems that the three University paintings, along with other of Klimt's works originally part of the Lederer collection, were taken immediately after the memorial exhibition to Schloss Immendorf in the wine region near the Czech frontier, north-east of Schongrabern, where they were destroyed by fire in May 1945.
As a result we must content ourselves – apart from the detail mentioned above – with black-and-white reproductions.
A text by Ludwig Hevesi provides the only evidence of what colours Klimt used:
“Klimt's Philosophy is a grandiose vision of almost cosmic inspiration... We have before us a fragment of space filled with mysterious fermentation, with movement and a rhythm at which we can only guess. The figures, too, are wrapped in a mystic vagueness which clouds the eye with colour. The artist's job is, as far as possible, to render this vision purely in terms of colour, for it is as colour that he conceives it. The space is filled with mingling colours: blue, violet, green and grey, and these colours are intertwined with a gleaming yellow that sometimes intensifies to gold. One thinks of cosmic dust and swirling atoms, of elemental forces seeking to become tangible. Swarms of sparks fly around, each one a red, blue, green, yellow-orange or flashing golden star. But the chaos is a symphony, and the artist's sensitive soul has mixed its colours. He dreams up a colour harmony, and the eye loses itself, dreaming, in the strange amalgam of those colours. In one spot a green mist has gathered... The longer you look at it, the more it takes shape: a stony, impassive face emerges, dark, like an Egyptian basalt sphinx... children, fresh young intertwined bodies embracing, joy and sorrow, labour, strife, life's struggle, creation, suffering, and at the end the passing away, the grey old man with his face buried in his hands, a feeble husk sinking into the depths. But from below a great, living head emerges, with wide-open eyes and red-gold hair, crowned with laurel leaves and girdled with veils: it has a finger to its lips, it holds its peace, and looks and meditates. It is bathed in a fiery light, it glows and flowers in its own splendour, it heralds a creative power equal to the chaos above. The apparition... is Knowledge or Philosophy...”