is determines how he acts. The natural, physical, biological, human and social worlds are the realm of God's immanent action, and therefore the manifestation of his creative presence (Peacocke 1986:129). Such a God can be learned of through nature, being ontologically identical to the God who is made known by means of Self-revelation. If such were not the case, the perception of God would fall subject to the Gnostic disjunction. Following on the work of such theologians as Torrance (2001:118) and McGrath (2002:306), I therefore wish to say that the Divine incarnation determines our epistemology. Christ functions as both the foundation of, and criterion for, an authentically Christian natural theology. Ontology, therefore, precedes the doctrine of an epistemology, resulting in a particular theological realism.10 A theology of nature, apart from working a posteriori, can also be regarded as taking the same direction that Charles Darwin took. McGrath (2002:158) regards On the origin of species as the best example of how, from a variety of opposing explanations, one can, eventually, find the best possible solutions. Charles Peirce termed the use of such a posteriori activity to reach the best explanation abduction. The vast range of observational data could best be explained by Darwin in terms of natural selection, rather than in terms of the special creation of species. Schleiermacher ([1999] 2008:738751) was correct in not placing the Trinity tenet at the forefront, as Barth does in his dogmatics, but at the end, as a conclusion of his theory of faith. That the Church has long first achieved insight into the Tri-unity of God illustrates well the classical expression: lex orandi, lex credenda. CONCLUSIONIn order to reach an evolutionary epistemology which overcomes the radical concept of dualism arrived at by the Enlightenment and to reopen the field for a Christian natural theology, it was necessary to configure at least two diachronic lines. On the one hand, we began at On the origin of species, which was read in context with William Paley's Natural theology, on account of the biological substrate which Paley advocated in his teleology, and the influence that his natural theology had on Darwin. Humankind's naturality is offered as a given in terms of evolution, which has a direct influence on our ability to know. People have a particular epistemological apparatus, resulting from the bio-cultural paradigm in which they find themselves. The brain is custom-made for, and by, its environment. Rather than resembling a computer, it is like a Swiss army knife, with its different components that are aptly suited to its various tasks (Haught 2003:104).On the other hand, it was necessary to deconstruct the standpoint of the doyen of a revelatory positivism, namely Karl Barth, in relation to Brunner's natural theology, with his ontological 'capacity for speech'. Barth should, as a child of his time, be read in terms of his outspoken opposition to the Liberal theology of the 19th century and the rise of German National Socialism in the 1930s. The ferocious verbal attacks that he launched against Brunner exposed the source of his problem: Nazism.11 The converse of his