We use the word "natural" in many senses,—sometimes with warm approval, as indicating that which is best; sometimes with disapproval, as low and discreditable.
"Natural affection" is one familiar phrase, and "unnatural monster" another, which show a firm belief in the rightness of the working laws of the universe.
On the other hand, the whole story of human development lies in changing those conditions and habits which were once natural to the slow, laborious, hard-won advantages of civilisation. "The natural man" or man "in a state of nature" is a remote ancestor; and we do not allow unchecked freedom to animal passions and appetites among us on the ground that they are "natural."
It is natural to take revenge for injuries; it is natural to eat too much; it is natural to be too careless in youth and too cautious in old age. "Natural" means according to the laws of nature; and the laws of nature have a wide and long range.
In applying the word to any one creature, we have to limit it by time and circumstance. It is natural for an absolutely wild creature, which has never seen man, not to be afraid of him. It is natural for the same creature, when hunted, to fear man, and shun him. If long tamed, like the cat and dog, it is natural to come trustfully to the well-known friend.
Nature is essentially changeful. Its laws remain the same, but the interaction of those laws produces ever-varying results. "The nature" of any given creature varies with its circumstances,—give it time,—as in the above case of the dog and cat; but the whole scale of behaviour is "natural" in its place and time. "A state of nature" is not a period with an exact date, nor any one grade of conduct. That conduct which is most advantageous to a creature under given circumstances is natural. The only conduct which is "unnatural" would be that which was exhibited in contradiction to the laws of nature, if such were possible.
In this sense an ascetic life is unnatural, as meaning destruction to the individual and race; but, in the sense that the ascetic fondly believes he is acting for his ultimate benefit, his conduct is "natural," after all.
A wild rose is "natural," a garden rose or hot-house rose is "cultivated," a velvet rose on a bonnet is "artificial." Yet it is as natural for man to cultivate and imitate for his own good pleasure as for a bee to store honey. When we were in what we usually call "a state of nature," we did not keep clean, wear clothes, go to school or to church. Yet cleanliness and clothing, education and religion, are natural products of "human nature."
When we apply the word to human conduct, we ought to be clear in our own minds as to whether we mean "natural"—i.e., primitive, uncivilised, savage—or natural,—suited to man's present character and conditions. Primitive man did not send his children to school, but we do not consider it unnatural that we do send ours. Primitive woman carried her naked baby in her arms; modern woman pushes her much-dressed infant in a perambulator. But there is nothing unnatural in preferring the perambulator. It is natural to do what is easiest for the mother and best for the baby; and our modern skill and intelligence, our knowledge and experience, are as natural to us as ignorance, superstition, and ferocity were to our primal ancestors.
With this in mind, let us look at the use of the term "natural" as applied to mothers. What sort of mother do we praise as natural, and what sort do we blame as "unnatural"? Is our term used with reference to a period of development, "natural" motherhood, meaning primitive, savage motherhood? or is it used with reference to the exercise of that intelligence, acquired knowledge and skill, and array of conveniences, which are natural to civilised man to-day? I think it will be found that in most cases we unconsciously use it in the first sense, natural meaning merely primitive or even animal, and with but too good reason, if we study the behaviour we are describing.