Technical flaws in the coherence theory

Conclusion

We have argued that Lehrer's definitions of coherence and justification have serious technical defects. As a result, the definition of justification is both too weak and too strong. We have suggested solutions for some of the problems, but others seem irremediable. We would also argue more generally that if coherence is anything like what Lehrer's theory says it is, then coherence is neither necessary nor sufficient for justification. While our current objections are directed at the ‘letter’ of Lehrer's theory, other criticisms can be aimed at its very ‘spirit’. We would argue that coherence is unnecessary for justification because of the existence of ‘basic beliefs’, those about self-presenting states (‘I have a tingling sensation in my leg’) or self-evident truths (‘All men are men’). Such beliefs may be justified even though there are no other propositions in the subject's acceptance system that makes them more probable than competitors. Coherence is, moreover, insufficient for justification, because it ignores the inferential structure of the subject's acceptance system, and requires no justification of any kind for the subject's acceptance system itself. But we must develop these more fundamental objections on another occasion.