If the purpose of life cannot be established, then we can only place arbitrary values on things. In other words, without a standard to measure against, we cannot claim that a true value exists for anything.
What this means is that we’re all of equal value, our decisions are of equal value, and our paths in life are of equal value. Without knowing life’s purpose, it’s invalid to say someone or something or some scenario is worth more or less than another.
On an individual level, this means that there are no bad choices, no reasons to regret, no wrong turns. Simply put: we don’t know why we’re here, so we don’t know what’s good or bad in the long-term.