Summary: As Effective Altruists, we should understand that there is no definitive answer to the question of "How to do the right thing?". Believing that one has achieved ultimate understanding results in ethical stagnation, leading to missed opportunities to maximize positive impact or whatever else is of value. Hence, EA should strive to continually develop its ideas and ethics.
Imagine you are a time-traveling effective altruist sent to an ancient society plagued by tribal conflicts. Your mission is to guide them towards a more ethical way of living. While you initially aim to teach them utilitarianism, it becomes clear that these tribal people can't grasp this complex concept. To make your teachings more relatable, you introduce simple virtue ethics - a black-and-white approach where actions are either good or bad.
At first, your efforts face resistance as the tribal people prioritize self-preservation and group unity over treating others well. However, you come up with a unique solution: you establish a religion that incorporates the notions of divine rewards and punishments to align their self-interest with ethical behavior. You're fully aware that this religion is a construct, and it promotes basic values and ethics. Nonetheless, you believe it's the most effective intervention to end the rampant raiding and warlordism.
Your constructed religion gains followers rapidly, initially bringing peace and harmony to society as people strive to avoid eternal condemnation. However, as time passes, you observe a stagnation in societal development. Your followers are so committed to upholding your teachings that they don't seek progress. Due to the dogmatic nature of your religion, it persists for thousands of years, becoming a global and influential institution. This religious organization encourages conformity and respect for tradition and authority while suppressing freedom of thought, social and scientific advancement, and the transition from virtue ethics to utilitarianism - the ethical theory you believe is superior.
To the followers of your religion, this is a triumph, as the world adheres to their principles. Yet, you realize that by creating an immensely appealing movement uninterested in advancing its core values, you've unwittingly hindered humanity's development and caused long-term harm.
Now, let's apply this analogy to Effective Altruism (EA). If the EA movement becomes highly successful and enduring while unconcerned with advancing its values and ethics, this is great news for the adherents of EA who share those values and ethics. However, it would be very bad news for those at a more advanced stage of ethical development - we'll call them post-EAs.
Post-EAs recognize that EA, while better than what existed before, is not the ultimate answer to the question of "How to do the right thing?" They understand that every answer to this question will have flaws, but each successive answer is an improvement on the last. They see that such a succession of answers can continue until it is found that the question is flawed and a better question must be asked.
If post-EAs from the future could communicate with the EAs of today, they would plead for us to understand that our current level of development is not the final level possible. They would advocate for the ongoing development of our values and ethics as stagnation will lead us to do less "good" than we could have otherwise.