The generally accepted interpretation of Kant's formula “act only on that maxim which thou canst at the same time will to be a universal law,” is roughly as follows:—
Our moral experience is fundamentally a consciousness of the difference between Duty and Inclination, between "doing what we ought to whether we like to or not, and doing merely what we like whether we ought to or not."1 When we have open to our choice different acts, there are some which we would like to do, others we would not like to do, and perhaps others towards which we are indifferent; or we like to do any one of them, or we may dislike all, or we may be indifferent to all. But we must ignore our inclinations, our aversions, our attractions, and our indifferences. We must ask ourselves which of the acts open to our choice ought we to do, no matter what our feelings in the matter may be.