Subscribing To The Naturalistic Fallacy

Martin (1992: 586):

Beyond this studies are needed on the inter-relationships between affect and morality (between ATTITUDE and MODULATION to put this grammatically): I like/dislike clearly conditions you should/shouldn't in ways that have been barely broached (see Martin 1992a).

Blogger Comments:

[1] The claim here is that

• the relation between affect (a neutral or charged tenor relation between interlocutors) and morality (principles of right and wrong) 
• can be described as 
• the grammatical relation between attitude (positive or negative evaluation) and modulation (obligation and inclination).

[2] The claim here is that the giving of information conditions the demanding of goods-&-services:

• propositions that are realised by declaratives of the form I like/dislike
• condition
• proposals that are realised by declaratives of the form you should/shouldn't.

In philosophy, the claim that an "ought" (prescription) can be derived from an "is" (description) is known as the Naturalistic Fallacy (G.E. Moore); see also Hume's Law/Guillotine.

In SFL theory, the mental processes that relate to modulation are not those of emotion (I like), but those of desideration (I would like).  This is because desiderative processes project proposals and can serve as interpersonal metaphors of modulation, as in I would like you to finish this by tomorrow.