Because self-love is such a strong element in human nature, it is easy to understand why so many philosophers have regarded it as the sole basis on which all moral judgments have been made. That they have been mistaken in this can be shown by applying what Francis Bacon has termed a "crucial experiment." This can be done by examining instances in which an individual's private interest is separate from the public interest and even opposed to it.
Situations of this kind are not uncommon. A person engaged in business may learn that his chief competitor has been stricken with a fatal illness or has become the victim of some horrible accident. If he is a person who reacts in a normal manner, he will experience a genuine sense of sorrow for the man who has suffered the misfortune. His sorrow will not have been brought about because of any harm to his own private interests but will be due to the fact that as a human being, he is naturally sympathetic toward others. Again it is perfectly normal for a person to rejoice over the good fortune of others even though it may have been brought about at the expense of what one may have desired for himself.
Prolonged solitude does not bring enjoyment to an individual. To be happy, one must share his experiences with others. No normal person can be in a cheerful mood so long as those who are close to him are in a state of misery. Who is not pained by the tears and cries of a little child? Whenever one encounters the signs of sorrow and mourning, he is bound to feel a sense of compassion and of uneasiness. Wherever we go, and no matter what type of society we are associated with, it is still true that the joys and sorrows of other people excite within our own breasts feelings of pleasure or of uneasiness. This is not because of any selfish feelings we have toward ourselves but rather because of the tendency in our own nature to be sympathetic toward the feelings of other people.
