to make way for the full strength and development of the central consciousness

I don't understand the part in italics. I know the meaning of each of the words used in this bit, yet I don't figure out what it's talking about. Would you explain it please?

Bronte's most profound innovation, however, is the division the Victorian female psyche into its extreme components of mind and body, which she externalizes as two characters, Helen Burns and Bertha Mason. Both Helen and Bertha function at realistic levels in the narrative and present implied and explicit connections to Victorian sexual ideology, but they also operate in an archetypal dimension of the story. Bronte gives us not one but three faces of Jane, and she resolves her heroine's psychic dilemma by literally and metaphorically destroying the two polar personalities to make way for the full strength and development of the central consciousness, for the integration of the spirit and the body. Thus Jane Eyre anticipates and indeed formulates the deadly combat between the Angel in the House and the devil in the flesh that is evident in the fiction of Virginia Woolf, Doris Lessing, Muriel Spark, and other twentieth-century British women novelists.

Elaine Showalter: A literature of their own, 1977

Solution 1:

Helen Burns may be taken a metaphor for an extremely optimistic, long suffering, forgiving and kind-hearted version of Jane Eyre. Or perhaps taken as a foil of that sort for Jane’s more pragmatic and realistic outlook on events and life.

On the contrary (a pole apart from Helen - polar opposites), Bertha Mason may be seen as a metaphor for an opposing metaphor of extreme of violent and unbridled female sexuality. She is convincingly placed in this distorted image of Jane by being wife to the conscientious and dutiful Mr Rochester, so that the reader is aware of her mirroring the developing, future and - ultimately - married connection between Jane and Rochester.

Helen dies in a rather “socially acceptable” Victorian way, of tuberculosis, making her an object of conventional pity; Bertha dies in a fire of her own making, with hints of the savage judgement of Fate. Thus it is that two extreme and opposing versions of womanhood (polar opposites), both of which have acted as parenthetic foils for Jane, vanish from the scene, leaving us with only Jane as a realistic sort of middle ground of femininity. Jane is left as an expression of "the full strength and development of the central consciousness" of herself.