The new humanism that arose at the time of the Renaissance turned out to be just that, humanism, not to be confused with humanitarianism, which is a commitment to acting humanely. The emphasis was now on man’s uniqueness, his free will, human potential and dignity. It is summed up in the phrase, ‘man is the measure of all things’, and it left non-humans as far behind as they had ever been.
Around this time, however, we do notice the first genuine dissenters. Leonardo da Vinci was teased by his friends for being so concerned about the sufferings of animals that he became a vegetarian. The notion was gaining ground that cruelty to animals was wrong in itself, quite apart from its tendency to lead to cruelty to human beings. Intellectual conditions seemed to be in favour of change. Things could only get better. Then along came Descartes.
Descartes taught that all material things are governed by the rules of mechanics, rather like a clock. Human beings are the exception in that they, we, are the only physical beings that also have a soul, a consciousness, specially created by God, which survives the decomposition of the body. Animals do not have a soul; that is, they do not have consciousness. They are mere machines, automata. They experience neither pleasure nor pain, nor anything else. The essential difference between an animal and a clock is that whereas a clock is a machine made by man, animals are infinitely more complex machines, made by God.
This account of what consciousness is neatly resolved two problems for Descartes. On the one hand it maintained belief in life after death which he thought was necessary to discourage immoral conduct. At the same time the belief that animals were without consciousness and feeling eliminated the ancient and vexing puzzle of why a just God would allow animals to suffer at all. The answer was, He wouldn’t, and they don’t.
For Descartes the doctrine had another fortunate result. The practice of experimenting on live animals was becoming widespread in Europe. As there were no anaesthetics, the animals being experimented upon appeared to be in extreme pain and distress. Descartes’ theory, if true, meant that he and other physiologists need have no qualms about dissecting live animals, because, as they were no more than machines, they could have no feelings and therefore could not suffer.
The outlook for non-humans could hardly have been worse. Curiously though it was these same experiments that revealed a remarkable similarity between the inner-workings of our human bodies and the bodies of those animals being experimented on. So alike were they that Voltaire was moved to ask whether Nature or God could possibly have arranged for animals to have all the organs necessary for feeling ‘to the end that they may not feel’? He condemned what he called the ‘barbarous custom of supporting ourselves upon the flesh and blood of beings that are like ourselves’.
Among others who contributed to the debate, were Rousseau who attacked the use of animals for food as unnatural, unnecessary, bloody murder; and the philosopher David Hume who made the more moderate claim that although we are entitled to use animals, we ought to do so gently. Immanuel Kant, on the other hand, considered animals as no more than a means to an end, the end being man. One answer to Kant came in the writings of Jeremy Bentham, of whom more later.