Or, for your whole phrase:

the identity of the knower, that which is known, and the act of knowing.


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Note added at 4 hrs (2010-01-05 21:23:39 GMT)
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That's the simple option, I think. And "knowledge" has been used for "сознание" in standard translations of Solovyov. If, however, there is a sustained, logical exposition in your text, then you might want to opt for what Chernyshov proposed, "the identity of the one who is conscious, the object of consciousness, and the act of being conscious," or something like that. Because there are places where Solovyov goes into great detail about this concept/act of сознание, including taking the word apart. Sorry that this quotation is from an English translation, rather than the original, because I'd like to confirm that it is also "сознание" which has been translated here as "knowledge" at the beginning of the sentence. Anyway, maybe it will be interesting:

"And this knowledge of fact - immediately and inseparably connected with the fact itself, always found with it, beside it, and therefore justly called con-sciousness [so-znaniye], con-scientia, Bewusstsein (i.e., Bei-wusstein) - must be acknowledged as absolutely valid because here knowledge directly agrees with its object, thought is a simple repetition of fact, judgment is the expression of pure identify: A = A."
From: Основы теоретической философии, trans. by Vlada Tolley and James P. Scanlan.