You would donate as much of your income as possible to effective charities and/​or dedicate your life to effective Altruist causes (however you determine that) because the utility derived from your income/​work is likely hundreds times greater applied rationally for the benefit of others than for your personal welfare, even with a 50% discount rate. You would have to have a very high confidence in sollipsism before it would be rational to live selfishly.
You would donate as much of your income as possible to effective charities and/​or dedicate your life to effective Altruist causes (however you determine that) because the utility derived from your income/​work is likely hundreds times greater applied rationally for the benefit of others than for your personal welfare, even with a 50% discount rate. You would have to have a very high confidence in sollipsism before it would be rational to live selfishly.