One sometimes hears it said that ‘the Church’ has changed its mind about evolution; Catholics are now allowed to believe in it, whereas formerly they were not. This is a thoroughly confused remark. Evolution is a biological theory, and biological evidence tells us whether it is true or false. It would he very odd to speak of a theory concerned with neither faith nor morals being officially accepted or rejected as part of the Catholic faith. But because the theory has implications which touch on the faith, Catholics looked for guidance from authority about the attitude they should take towards it where those matters were in question: guidance now given them in the encyclical Humani Generis, which encouraged theologians to investigate those points where the theory bore on truths of faith. The present article is not concerned with the biological evidence, which I accept, nor with an extended theological investigation, but merely with difficulties which Catholics still seem to have about the theory, and which are really philosophical in kind.

The first difficulty lies in the conflict which people still find between the theory of evolution and divine providence. How can we say that God directs the whole course of history if rigid scientific laws determine the way in which living things developed from inorganic matter, and finally evolved man? The problem is really that of understanding how causes in the natural world are related to the causality of God. People tend to think that if natural causes are not independent of God, their dependence must imply his constant interference with them to bring about what he wills.