I am re-reading Colin Wilson's excellent book about Rudolf Steiner: the man and his vision (1985) - which he opens by saying that Steiner's core assumption is twofold: that there is a super-sensible, spiritual world hidden 'behind' the everyday world of the senses - and from-which the perceived world is derived. And secondly; that thus world is knowable by those who choose to develop their latent abilities.
So far, this is hardly distinctive; except that the way in which the hidden ('occult') world was discovered was not by trance, dream or other 'hallucinatory'-state but by an intensification of the alert, awake, clear thinking that Steiner regarded as characteristic of science.
Steiner therefore called his practice a Spiritual Science (and the specific type of spiritual science he recommended, he termed Anthroposophy).
But when we are told of a spiritual world behind the perceptual world; this naturally seems to evoke a picture in our minds of two perceptual worlds.
In other words, we often imagine the surface everyday world of solid-things, then - separated from it by a barrier - another world of spirit-things.
When we imagine ourselves knowing the spiritual world, therefore we imagine seeing/ hearing/ touching the spiritual world by something like of an extra set of new senses.
At times, especially in his later career as a leader in the Theosophical Society then originator of Anthroposophy; Steiner writes exactly like that about his own experiences.
Steiner describes (what seems like) observing events of the life of Jesus, or the evolution - and re-incarnation - of the earth; and/or the history of reality in 'Akashic' records that sound like scrolls recording everything that ever happened, but which can be seen and read by inner sight.
This seems exactly like traditional religious experiences of a 'hallucinatory type'; seeing visions, hearing voices, perceiving other times and places... But with the difference that Steiner had these experiences - not in the context of a trance or dream or religious ecstasy, but in everyday waking consciousness.
But at other times, Steiner seems to be clear that the understanding of supersensible reality comes by direct understanding, into the realm of thinking; and therefore Not by means of observing inner perceptions with new inner senses.
(This is the message of his early books Science and Knowledge, and The Philosophy of Freedom.)
It is envisaged as learning without the intermediary of first perceiving some kind of representation like a picture, and then needing to understand what one has perceived. But with direct-knowing, instead the understanding comes into our thinking without mediation - the subjective experience is that knowledge simply 'arises' in our thinking.
Such a mode of direct and unmediated knowing, is a much rarer and historically more distinctive way of penetrating to the hidden world of the spirit.
My conclusion is that Steiner did both: Sometimes he perceived the hidden world of spirit with inner vision: Other times he knew the hidden world directly, in thinking.
But he failed always to be clear about which he had done, and about which was the better mode of knowing.
Of these; direct-knowing is the more fundamental and potentially valid way of understanding the hidden spiritual world; because any form of inner vision must entail the further step of interpreting its meaning.
Whereas (by my understanding - not Steiner's) the perceiving mode provides a very high volume of potentially very specific information - but its validity is much less than direct knowing.
Because this kind of perceptual information can be 'manufactured' by learnable techniques of meditation, and produced almost at will by those with aptitude. Yet, at the level of specific detail, each such 'visionary' will produce his or her own unique and unreplicable description from observing the hidden world - as can be seen from comparing (say) Swedenborg, Blavatsky and Steiner; or the various New Age channelers of the late 20th century.
(Although Steiner seems to have copied then modified a great deal of Blavatsky's general descriptive scheme of metaphysics and history.)
To avoid confusion; we would need to avoid talking about the super-sensible world in ways that conjure up an inner world of pictures, stories, observed beings.
We would need to cease talking about experiences such as watching the work of angels, reading the Akashic records, hearing the words of spiritual guides and the like, feeling our hands driven to engage in automatic writing - and other similar things.
In sum: There is a hidden spiritual world, and it can be known; but it is ultimately known-by-knowing, therefore not known by (yet another) layer of perceiving.