For the nonce we must be content to generalize from our own premises, only rising above them sufficiently to get a bird's-eye view of our neighbor's estates.

Such a survey has at least one advantage: the whole field of view appears perfectly plain.
Surveying the subject, then, from this ego-altruistic position, we can perceive why matrimony, as we practise it, should result in increasing the personality of our race: for the reason namely that psychical similarity determines the selection.

At first sight, indeed, such a natural affinity would seem to have little or nothing to do with marriage.

As far as outsiders are capable of judging, unlikes appear to fancy one another quite as gratuitously as do likes.

Connubial couples are often anything but twin souls.