From AnthroWiki

Then you have to trust your senses,
No falsehood will they let you see
When your mind keeps you awake.
With fresh eyes joyfully notice,
And walk, as sure as smooth,
Through the meadows of a richly gifted world.

from Goethe: Vermächtnis

Illusion occurs when subjective perception does not correspond to the objectively given, external, physically ascertainable reality. As Goethe already remarked and as Rudolf Steiner also affirms, this is not actually a sensory illusion, but rather a false judgement of what is sensually experienced due to a processing of the sensory data that is not appropriate to the external reality. A genuine sensory illusion only exists if the sense organ itself is damaged.

„With regard to cognition, one can speak of truth and error. Now does error arise already in the region of the senses, or only there, where through judgement, memory, etc., ideas are formed about the statements of the senses? Are ideas formed about the statements of the senses? One has a right to speak of sense illusions. If, through an irregularity in the ear or in the eye, a sound or an impression of light appears different from what it would be if the organs in question were normally formed, then, for instance, there is a deception of the senses. Is it therefore unjustified what Goethe said: "You may boldly trust your senses, they will not let you see anything wrong if your mind keeps you awake"? Goethe's sentence immediately proves to be justified if one considers the following. An error brought about by reason or memory is of a different kind from an illusion of the senses. The latter, in fact, can be corrected by the sound mind. If, through an error of the eye, a tree standing in front of someone presents itself as a human being, he will only be in error if he does not correct the error of the eye and sees in the pretended human being an enemy against whom he fights back. It is not so with an error of the intellect, for there it is this intellect itself that errs, and which therefore cannot at the same time correct its own errors. - The deceptions of the senses only become real errors through the intellect. This distinction is not pedantry, but a necessity.“ (Lit.:GA 45, p. 20f)

Even if one sees through the misjudgement with an alert mind, however, the experienced perceptual illusion often cannot be overturned, since the processing of the sensory data takes place in an area that is hardly accessible to our consciousness. In truth, in this case it is a matter of a false imagination that cannot be influenced arbitrarily, or hardly at all, but can nevertheless be seen through with the mind. Perceptual illusions can affect all external senses; the most common are optical, acoustic, haptic and thermal illusions.

As a phenomenon of consciousness, illusionary misperception is closely related to this, which, in contrast to hallucination, is accompanied by a disturbed perception of real existing objects. Objects are reinterpreted or object features are alienated: for example, a - real - dog may appear to be a werewolf. Those illusions can very easily arise when our ability to judge is unsettled by a lack of sensory data. In twilight, for example, the shadow of an object can easily be mistaken for a crouching figure.

Such illusions can increase pathologically to the point of delusion. According to Rudolf Steiner, they are based on faulty memory formation. In this way, forces are released that should actually only become effective in the next earthly incarnation. What we experience and do in one incarnation is imprinted on the memory, the organic basis of which, according to Steiner, is to be found above all on the surface of the inner organs. If, for example, it is a matter of remembering very abstract thoughts, then the surface of the lungs is extraordinarily strongly involved in this. These memories normally become visible in the shaping of the skull of the future incarnation. However, if these forming forces are already released in the present incarnation, they lead to delusional illusions, which can often be noticed in severe lung diseases.

„If one does not properly control what is stored up in the lungs, then it is squeezed out, as I said yesterday, that a sponge is squeezed out, and then from what should actually only come out in the next incarnation in a head-forming way, preferably such abnormal phenomena arise which are usually called obsessive thoughts or also in some way illusions. It is an interesting chapter of a higher physiology to study in lung patients what strange ideas appear there in the high stage of lung disease. This is connected with what I have just explained, with this pressing out of thoughts. The thoughts that are pressed out are therefore compulsive thoughts, because they already have the forming power in them. The thoughts that we should now have normally in our consciousness must only be images, they must not have a formative power in them, they must not force us. During the long time between death and the new birth, they force us, they are causalities, they have a formative effect. Now they must not overpower us, they may only exert their power in the transition from one life to another.“ (Lit.:GA 205, p. 102f)

Delusional illusions can occur as a symptom in all types of psychoses, but especially in organic psychoses (e. e.g. in the context of alcohol poisoning or brain injury), but also in migraine, in epilepsy or in overtiredness.


References to the work of Rudolf Steiner follow Rudolf Steiner's Collected Works (CW or GA), Rudolf Steiner Verlag, Dornach/Switzerland, unless otherwise stated.
Email: URL:
Index to the Complete Works of Rudolf Steiner - Aelzina Books
A complete list by Volume Number and a full list of known English translations you may also find at Rudolf Steiner's Collected Works
Rudolf Steiner Archive - The largest online collection of Rudolf Steiner's books, lectures and articles in English.
Rudolf Steiner Audio - Recorded and Read by Dale Brunsvold - Anthroposophic Press Inc. (USA)
Rudolf Steiner Handbook - Christian Karl's proven standard work for orientation in Rudolf Steiner's Collected Works for free download as PDF.