Every fortnight I have the stimulating pleasure of leading a group on
philosophy, under the auspices of the University of the Third Age. Our range
is wide but, over the years, we have returned time and again to questions of
morality. Given the diversity of backgrounds –­ Catholic, Jewish, Muslim and
agnostic –­­ you might think that we had so little in common that serious and
probing debate would be pointless. On the contrary. Although we often agree
to disagree on particular questions we share fundamental principles in
common, and we are always ready to give reasons for the conclusions we
defend.

This is what is known as the natural law in action.

The protagonist of natural law in the western tradition is Thomas Aquinas.
Even the secular philosophers who write about the concept, and maintain
their variations, have Aquinas on their shoulder. And behind him stands
Aristotle.

The first principle is that practical reason obliges us to follow the good
and avoid the evil. We may be wholly mistaken about what constitutes the
good in a given instance, but that is what reason obliges us to follow.
However, we achieve our basic understanding of the good through our
understanding of nature, because acting in accordance with nature ensures
that we are directed at the right target: that is, we flourish.

A simple example is provided by the dog. The nature of the dog, among other
things, is to be active, to give and receive affection, and to relate
closely to human beings. (We might note here that some key characteristics
of this nature have come about through evolving from the wild, ancestral,
species.) If we treat a dog in accord with its nature, it flourishes. If
not, not.

In a recent column, I looked at how we could discover the role of
fatherhood through looking at the needs of human nature. Human nature is
qualitatively more complex because it is a fusion of animal nature and
spiritual nature. That is, it involves elements such as intelligence, free
will and moral responsibility. We often speak of two natures –­ the lower
nature and the higher nature ­– but this is just a convenience for discussion
because the two interpenetrate in ways we cannot completely understand.

Aquinas speaks of a hierarchy in our grasp of what human nature requires to
flourish. There are major constituents such as justice, responsibility to
neighbour, right to life and conscience and so forth. These are recognisable
by all. But as we move down the hierarchy towards more detailed application
of these major principles so there is greater and greater room for
disagreement. This can come about because our understanding of human nature
and circumstance inevitably varies at the more detailed level, and so we
arrive at different conclusions. Nevertheless, the UN was able to proclaim
an agreed code of human rights, and call it “universal”. Such declarations
implicitly stem from natural law.

More importantly, grasp of natural law can vary because of ill-will and bad
habits. We know that it can also be distorted through culture. Decent,
commonsense people (such as many in my group) broadly accept our current
abortion laws; we live in an abortion culture, and those out of line are
considered indoctrinated or eccentric. So, for such reasons, deliberate or
indeliberate, we may be blinded to what natural law demands.

Can natural law change? Certainly our knowledge of it can. For instance, a
mistaken understanding of embryological development, which science corrected
in the 19th century, led to a change in the status of abortion. And
perception can change. The deeper understanding of conscience which led
Vatican II to accept the fundamental human right to free choice of religion
was an unacknowledged reversal of a long-standing Church teaching.

Circumstances can change, too. The general proposition that cannibalism is
always wrong might be questioned should a group find themselves abandoned in
a remote area and without food after, say, an air crash in which one of the
party had been killed. In America in the 1880s the average woman gave birth
to about seven children. And this was necessary to maintain the population
because child mortality meant that only two or three children would survive
to procreate. Today such an average birthrate would lead over a few
generations to an astronomical increase in population. Do the maths. Such
examples remind us that we cannot invariably generalise about what is needed
for humans to flourish.

So far my description has been couched in terms of unaided human reason.
Consequently we can debate the application of morals in the public forum.
And it does not follow that atheists can have no moral sense. In fact their
attacks on religion are often made in moral terms. They may have difficulty
in explaining the source of moral obligation, but that is not the same as
lacking it. Christianity, through St Paul, describes it as a law written by
God in men’s hearts. And indeed we hold that the imperatives of the natural
law fundamentally arise from the fact that God created our nature.

The Church goes further, declaring that she has a special competence to
interpret the natural law with an understanding illuminated and enriched by
Revelation. Undoubtedly the concept of what it means to flourish is
marvellously extended when human nature is understood as elevated by
redemption, and created for an eternal destiny. But there remains a need to
demonstrate the link between natural law as open to reason and its deeper
application. For example, while natural law can make a very strong case for
monogamous marriage, it has a higher imperative derived from Christ’s
declaration that monogamous marriage was intended for the human race from
the beginning. For the believer, but not the sceptic, the case is closed.

The need to demonstrate this link is particularly great when a moral
teaching which allows of no exceptions is declared. Sadly there have been
occasions where accepted doctrines have needed to be modified or abrogated.
Moving beyond the limits of human reason, where Revelation gives no certain
mandate, can be a hostage to fortune.