With the concept of justification, we enter back completely in the assumptions of the left hemisphere of the brain. It may often be the case that the right hemisphere makes implicit, unconscious judgements, but the reasoned, explicit ones that we are conscious of are made in the left hemisphere. It is through these explicit judgements that we maintain whatever degree of control we may have over our response to conditions. Even if they do not determine our actions at a given time, they must contribute in the longer term or we would be impotent to shape ourselves or the world. Unless we accept the metaphysical dogma of determinism, which we have no grounds to do if we rely on experience (see IV.4.c), we must work on the assumption that our judgements do make some difference and thus that we should try to make them as objective as possible.

But how should we do this? This is where we need a theory of justification. The terms foundationalism and coherentism are used in epistemology to refer to two contrasting kinds of justification[1]. A foundationalist theory is one that derives justification of a particular claim from its relationship to a foundational claim that is assumed to be true. The analogy is of a house of beliefs being built on foundations of certainty. Thus Descartes’ philosophy is a classic example of a foundationalist philosophy, because it builds up further justified claims from the cogito, the allegedly proven claim that ‘I exist’. In contrast, a coherentist theory is one that derives justification for a claim from its coherence with a set of other claims that are already accepted, even if all these claims taken together have no ultimate foundation. These two theories contradict each other because a foundationalist would accept a claim derived from a foundation of certainty even if it contradicted every other claim he otherwise believed, whereas a coherentist would accept a claim that was consistent with her other beliefs regardless of whether it had a foundation.

These two theories at the outset also seem to be the only two possible ones, because coherentism is the only possible alternative when foundationalism is rejected (assuming we want some kind of justification). The direct opposite of foundationalism is just the absence of any justification due to the lack of foundational support. However, in practice, when there is no foundation our experience relies on a coherency of justification. For example, if a random disconnected experience popped up – say a mini flying saucer hovering over my soup – I would rely on the incoherence of this experience to conclude that I was not justified in believing in it. All evidence that arrives to us via the senses seems to rely on coherence, unless we have some foundational reason for believing that the senses must be correct.

The third theory also often mentioned by analytic epistemologists, reliabilism, can immediately dismissed because it is externalist or “non-inferential”[2] – that is, it ignores the question of whether we are aware of our justification, and claims that we are justified if we derive our belief from a reliable source, whether or not we are aware that it is a reliable source. In its abstracted reliance on an absolute standpoint beyond experience this theory has ruled itself out of all relevance to justification in relation to our experience, apart from the fact that the idea of a reliable source otherwise looks suspiciously like another sort of foundation.

My rejection of positive foundationalism will probably come as no surprise to anyone who has read thus far. By positive foundationalism I mean a theory of justification that assumes that any claim deduced from a positive metaphysical claim that it is assumed must be true. Positive foundational claims can be identified with positive metaphysical claims because they have no further justification – they are taken to be either self-evident a priori (see 1.f) or revealed from an infallible source such as God (see 1.g). Positive foundationalism, in effect, is positive metaphysics and positive dogma. Although another possible form of positive foundationalism is empiricist, this would require us to accept the evident justification of our senses without regard for the assumptions with which it had been interpreted or for its coherence with our other beliefs (see 2.e on empiricism).

However, a rejection of positive foundationalism does not necessarily imply a rejection of foundationalism altogether. Given the mutual exclusivity of foundationalism and coherentism, a total rejection of foundationalism would seem to require that we could not adopt any criteria other than those of coherence when judging justification. This, as we will see in the next chapter on coherentism, would be an unsatisfactory commitment to make. 

[1] See, e.g. Everitt & Fisher (1995) chs. 5-8

[2] Everitt & Fisher (1995) p.63 ff