Atheism and Theism 107possession of the one property necessitates possession of the other. Yet trian-
gularity and trilaterality are not the same attribute, and it takes geometrical
reasoning to show that these properties are necessarily co-instantiated. This
latter possibility raises what for the empiricist is the spectre of a priori know-
ledge, i.e., true, appropriately warranted belief that does not require to be
verified in experience – because it could not fail to be.
These are various aspects of a general problem for the naturalist. Our
concepts transcend material configurations in space–time. As was observed
earlier, to think of an item is always to think of it via some conception.
A naturalistic account of experience and thought will need to relate such ways
of thinking to the nature of the objects in question, and very likely add that
the genesis of our concepts derives (in whole or in part) from the causal
influence on us or on earlier generations of particular material objects. The
trouble with this is brought about by the trilateral /triangular example. To
the extent that he can even concede that there are distinct properties the
naturalist will want to insist that the causal powers – as he conceives them –
of trilaterals and triangulars are identical. Thus he cannot explain the differ-
ence between the concepts by invoking causal differences between the members
of their extensions (as one might seemto be able to account for the difference
between the concepts squareandcircle). For any naturally individuated object
or property there are indefinitely many non-equivalent ways of thinking about
it. That is to say, the structure of the conceptual order, which is expressed in
judgements and actions, is richer and more abstract than that of the natural
order, and the character of this difference makes it difficult to see how the
materialist could explain the former as arising out of the latter.
In summary, I have been arguing that there is a good deal of life remaining
in ‘old style’ design arguments. Evolutionary theory, and naturalism more
generally, are not equipped to explain three important differences which com-
mon sense and philosophically unprejudiced science both recognize: those
between the inanimateand the animate; the non-reproductiveand the repro-
ductive; and the non-mentaland the mental. Assuming a history of develop-
ment, these differences involve a series of ascents giving rise to explanatory
gaps in evolutionary theory. Naturalism, in its modern materialist versions,
has negative and positive aspects. It precludes certain sorts of explanations on
the grounds that they are incompatible with physicalism, and it presumes the
availability, in principle, of wholly adequate naturalistic accounts of reality.
I have been arguing that in its negative aspect it begs the question in its own
favour, and that its positive claim is demonstrably false in respect of one or
more features of the world.
One reaction to this might be to concede both aspects of the case against
naturalism, yet to query whether it advances the cause of theism. Philo-
sophers and others have written disparagingly of ‘God of the gaps’ apologetics,