I'd like to describe a scenario and understand what sort of general philosophical tools or schools of thought may be used to answer the question one way or another. The scenario involves an individual deciding whether or not to vote in a municipal election.
Suppose I am trying to decide whether or not I should take an hour out of my day on a Tuesday night to go and cast a ballot in the mayoral election. If I vote, I know for whom I will vote. I live alone and can safely assume that no other members of the public will know whether I vote or not. Therefore, my decision has no impact on the votes cast (or not cast) by the rest of the electorate. Given a sufficiently large municipality, my vote will be one in tens or hundreds of thousands. Therefore, the probability that my decision to vote or not has any impact on the result of the election is vanishingly small. For sake of argument, imagine a population infinitely large so that the probability of my vote swinging the result is zero. Therefore, I can safely choose not to vote with no impact on the election itself. Voting has a negative impact on me, as I'd rather not spend an hour doing it.
Here's the question: taken from the perspective of the individual, we see a decision that on the one hand has no impact on society or the decision maker (not voting), and on the other hand has a small negative impact on the decision maker and no impact on society (voting). Therefore, the net utility of voting is lower than the net utility of not voting (if you count the utility of the decision maker, equal otherwise) and it is not ethically wrong to abstain from voting. This notwithstanding, if every individual or many individuals made a decision to not vote following the preceding logic, then there would be a large impact on the election result. Assuming a low voter turnout is of negative utility to the public, if many people decided not to vote then the result would be bad. Therefore, is it in fact ethically wrong not to vote since if many people did it then it would be bad for society?
Thanks for reading my question. I'm hoping to hear your thoughts not just on the example I chose but on the general problem itself. Is an action wrong if it doesn't hurt for one person to do it but it hurts if everyone does? I chose voting simply because the individual impact of one vote can be reduced to almost nothing within a large voting body. If there are logical or philosophical inconsistencies in my question - tear them apart!