Some took the view that Mary, the weaker twin, did not have a worthwhile life, due to her degree of disability. Indeed, some maintained that Mary's life had a negative value - most notably Mr Justice Johnson of the High Court. Polly Toynbee went further in suggesting in the Guardian that neither twin's life was worth preserving. Siamese twins were, she said, 'fascinatingly horrible freaks of nature' and a 'monstrous abnormality'. There is, however, no such thing as a life of no or negative value.
Life is a basic human good, along with other basic human goods.
Even if Mary was seriously disabled, there was a value simply in her presence in the world. The implication of life having value is not that we should go to all possible lengths to preserve it. The good of life must compete with other goods, and with life in other patients, when it comes to allocating resources. However, there are negative rights attached to life which always need to be respected, whatever our duties to promote life. Life may never be deliberately attacked, by act or omission, in an innocent human being.