I have seen the following argument in several places:

Consciousness cannot be an illusion, and it surely exists.

An illusion is perceiving something to be true when this something is not actually the case. "Perceiving" and "being conscious of" can be taken to be synonymous, so saying that consciousness is an illusion is a contradiction.

The argument is very strong as it relies on semantics.

What is the first written philosophical account of this argument?

  • Well, there is Anaxagoras and nous; but there's likely to be earlier references in the Upanishads. Feb 24, 2016 at 0:40
  • @MoziburUllah you seem to know this area pretty well, can you elaborate a little bit? Feb 24, 2016 at 0:56
  • @smith: elaborated... Feb 24, 2016 at 4:34

4 Answers 4


1) Taken your question literally: One does not need to argue that consciousness exists. Everybody when awake is conscious and experiences consciousness.

One can discuss whether every perception is a conscious perception. Because we know that humans can also be triggered by unconscious stimuli. This kind of stimulation is used by marketing mechanisms or by priming, applied in an experimental context of cognitive psychology.

2) Hence the question is not, whether consciousness exists. The questions are:

  • How to define conscious mental processes and how to establish the border to unconscious processes?

  • Why are some mental processes conscious while others are not? What is the function of conscious processes?

As an introduction I recommend Koch, Christof: Consciousness - Confessions of a Romantic Reductionist. (2012). Chapter III reviews some definitions of conscious processes, taken from different view points.

Whether a person is conscious or not and to which degree he is conscious can be derived from its behaviour. That’s a method used by paramedics using a checklist.

A more refined criterion to decide about the conscious state of a person is to check the activity of the neocortex and the thalamus.

A more philosophical definition of being conscious is to register how things seem to us (qualia).

In any case, conscious mental processes are restricted to the neocortex.

3) An early classification of states of consciousness is given by the Mandukya Upanishad from the beginning of the common era. The Mandukya Upanishad distinguishes four quarters of atman (= the self):

  • Vaisvanara: “situated in the waking state, perceiving what is outside […]” (verse 3)

  • Taijasa: “situated in the state of dream, perceiving what is inside […]” (verse 4)

  • Prajna: “situated in the state of sleep – deep sleep is when a sleeping man entains no desires or sees no dreams […]” (verse 5)

  • “They consider the fourth quarter as perceiving neither what is inside nor what is outside, not even both together; not as a mass of perperceptions […]” (verse 7)


Anaxogoras, of Clyzomanae in Asia Minor, around 500 BC write of nous as an ordering force in the cosmos:

B12: Nous is unlimited and self-ruling and has been mixed with no thing; but is alone itself, by itself ... and nous has control over all things that have soul, both the larger and the smaller; and nous controlled the whole revolution, so that it started to revolve in the beginning.

Roughly a century earlier, in Miletus, Thales had supposed (reported by Aristotle in On the Soul):

all things have souls

In the scriptural corpus of Vedantic Philosophy, the principal Upanishads have a composition date around the turn of the 1st milleneum BCE; the Eesha Upanishad, has:

The Self is one. Unmoving, it is swifter than the mind. The senses lag, but Self runs ahead. Unmoving it outruns pursuit. Out of Self comes the breath that is the life of all things.


The Self is everywhere, without a body, without a shape, whole, pure, wise, all-knowing, far-shining, self-depending, all transcending; it assigns to every period, it's proper duty.

The Self, is sometimes translated as Consciousness; earlier translations had used soul, which had distinctly Christian overtones - which is possibly why Yeats opted for Self in the collaborative translation, excerpted above; (and possibly, the same artifact of translation is apparent in the translations of the Greek above).


Upanishads would be the earliest. One of the Mahavakyas ('Great Sayings') of the Upanishads (there are 4 in total) is Prajnanam Brahma - Consciousness is Brahman. It appears in the Aitareya Upanishad III. i. 3. The Aitareya Upanishad is part of the Rig Veda, considered by many as the oldest Veda. Most consider the Vedas at least 1500 BC. Verses 2-3 says (Swami Nikhilananda translator):

It is the heart and mind. It is [known in accordance with its different functions, as] consciousness, lordship, knowledge [of arts], wisdom, retentive power of mind, sense knowledge, steadfastness, thought, thoughtfulness, sorrow, memory, concepts, purpose, life, desire, longing [for sense-objects]: all these are but various names of Consciousness (Prajnanam).

He is Brahman, He is Indra, He is Prajapati: He is all these gods; He is the five great elements--earth, air, akasa [space], water, light; He is all these small creatures and the others which are mixed [with them]; He is the origin [of the moving and unmoving]--those born of an egg, of a womb, of sweat, and of a sprout; He is horses, cows, human beings, elephants--whatever breathes here, whether moving on legs or flying in the air or unmoving. All this is guided by Consciousness (Prajnanam), is supported by Consciousness. The basis [of the universe] is Consciousness. Consciousness is Brahman.


Upanishads are earlier recorded arguments on consciousness and other internal phenomena. You can browse various translations of these scriptures in English.

P.S. It seems any reference to Indian Philosophies are getting negative voting on this site.

Edit: Aitareya Upanisad from the rigveda which is older than any given scripture.

An English translation of one of the Sloka:

III-i-3: This One is (the inferior) Brahman; this is Indra, this is Prajapati; this is all these gods; and this is these five elements, viz. earth, air, space, water, fire; and this is all these (big creatures), together with the small ones, that are the procreators of others and referable in pairs – to wit, those that are born of eggs, of wombs, of moisture of the earth, viz. horses, cattle, men, elephants, and all the creatures that there are which move or fly and those which do not move. All these have Consciousness as the giver of their reality; all these are impelled by Consciousness; the universe has Consciousness as its eye and Consciousness is its end. Consciousness is Brahman.

Here you guys can find numerous iterations of consciousness word.

Other Upanishad from Rigveda:











  • 1
    The question is specifically when the first written version of the argument presented in the OP to the effect that consciousness exists occurs. Can you cite a particular upanishad?
    – virmaior
    Feb 25, 2016 at 8:38
  • The words Buddhi and Jnana exist in our scriptures way before any other . These words are in sanskrit.
    – syamal
    Feb 25, 2016 at 9:22
  • Okay ... that's not really a response to what I suggested you add to your question.
    – virmaior
    Feb 25, 2016 at 12:53
  • 1
    Can you cite a particular upanishad? In other words, edit your answer and add it.
    – virmaior
    Feb 25, 2016 at 13:02
  • 1
    I would downvote an answer that, for example, saying "sure, this thing is discussed in the Bible, here are the books of the Bible where it's mentioned," but then didn't provide (1) actual citations (so someone can look it up) and (2) quotes, and (3) some sort of exposition for how the passage is relevant. In that vein, I don't know what the list of Upanishads is doing in this answer... Do they all mention consciousness? Are they entirely about consciousness? Also, the question at hand is what is the first discussion of consciousness: was one of the upanishads written before others? Feb 26, 2016 at 19:14

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