Often the question is put: how can Anthroposophy prove what it claims? People ask for proof because the usual way to prove facts is not available for Anthroposophy. Therefore, some people dispute the scientific validity thereof; they do not take into consideration the following – I can explain these things only approximately, but they apply in the most accurate, exact way -: the person who needs proof, thus shows that what must be proven, is not sense-perceptible. We need proof whenever we have no perception. Should I need evidence that there was a man in this room yesterday, it will only be because I did not see the man myself.
Thus, it is with everything, concerning the historical development of humanity, we always need the evidence as well. When people still had an instinctive knowledge, they had a natural inner experience of what they called the Divine Being, did not need proof. The evidence for the existence of God only started to be required when during the development of humanity this spiritual perception was lost. The evidence is only needed where understanding is not available.
The Anthroposophical method, however, prepares the human soul to discover the spiritual. When it is described – that is the peculiarity about Anthroposophy-, it can be explained with healthy common sense and understood in the way a non-artist can recognise a work of art, although he cannot create it. One can therefore not object to the fact that only the seer can investigate Anthroposophy. For even if another person cannot examine it, it can be understood by anyone, who wants to use his healthy common sense without bias.
Source (German): Rudolf Steiner – GA 82 – Damit der Mensch ganz Mensch werde – The Hague, 12 April 1922 (page 200-202)
Translated by Nesta Carsten-Krüger