"A strong sense of identity gives man an idea he can do no wrong; too little accomplishes the same"

Djuna Barnes, a formidable literary figure known for her permeating insights into human nature, presents an extensive paradox in this quote. At its core, the declaration considers the psychological and ethical measurements of individuality and self-awareness.

The first part of the quote, "A strong sense of identity provides male an idea he can do no wrong", recommends that individuals with a distinct self-concept might develop a hubristic guarantee in their actions and beliefs. When someone has a robust sense of identity, they typically have clearness about their values and beliefs, which can be empowering. Nevertheless, this empowerment can sometimes change into arrogance. With a strong sense of self, people might start to overestimate their infallibility, leading them to dismiss criticism and ignore individual defects. Hence, their strong identity ends up being a kind of psychological armor that inclines them to ethical blindness, fostering a belief in their own ethical and intellectual superiority.

Conversely, the second part, "too little achieves the exact same", addresses the other end of the identity spectrum: those with a weak or underdeveloped sense of self. Such people might do not have clarity about their worths or direction, resulting in a type of ethical relativism. Without a strong internal compass, they might wander aimlessly, justifying actions as required adaptations to their situations, instead of choices grounded in a consistent ethical framework. This fluidity can also lead to a type of moral invincibility, where actions are detached from consequences because they do not considerably impact an underdeveloped sense of identity.

Thus, Barnes recommends that both extremes-- a highly defined sense of identity and an underdeveloped one-- can result in a comparable result concerning ethical conduct. In both cases, people become detached from the nuanced ethical complexities of their actions. Therefore, the quote works as a cautionary reminder of the need for balance: maintaining a sense of identity without catching egotism, and avoiding the mistakes of identity diffusion that lead to ethical uncertainty.