In this article, I will examine the distinction between analytical and synthetic naturalism. This division was first proposed by Kant in his attempt to find evidence that there seemed to be knowledge known independently of any particular (a priori) experience, and shared by all. (WEST) The aim is to show that synthetic naturalism is a plausible theory in meta-ethics, although it faces major criticism. I- Analytical naturalismAnalytical naturalism consists of affirming that moral properties, like morally bad ones, are synonymous with natural properties. The use of a moral term, “S,” is governed by the definition to which the speaker attaches it. (Jackson 1998) It therefore seems that analytical naturalism is linked to sematic internalism. This means that a definition of a term is given solely based on how things appear in a given speaker's mind; anything from the external environment does not contribute to the content of the terms spoken by the person. (Rubin)II- Synthetic naturalismSynthetic naturalism says that there is an a posteriori identity between moral and natural properties. For example, there is an identity claim that water is the same as H2O. Something which is water must therefore also be the quantity of H2O. (RUBIN) This is considered synthetic because the associations between water and H2O can be completely different. The truth about water was discovered through empirical work, thus making it ex post facto. Synthetic naturalism proposes adopting externalist semantics for moral and property terms. Externalist semantics allows two terms to refer to the same property, even when the meanings are different. (PLATON STANFORD) It follows, then, that the meanings of the terms ...... middle of article ...... the meaning of the moral and twin moral terms differ. Even if a specific natural property can regulate our use of “right,” we can still question whether that property is actually “right.” IV-ConclusionThe analytical and synthetic distinction lies in the middle of a great debate in philosophy due to the lack of clarity. in both theories. The explanations and objections raised here have proven that analytical naturalism cannot be plausible because it applies proper names to natural terms. The analytical naturalist could respond by adjusting the theory and saying that moral terms need not be equivalent to natural terms, but this seems unlikely since this is the heart of the argument. This therefore leaves us with a synthetic naturalism, which allows us to engage in moral disagreements between speakers. Moral disagreement is fundamental if we are to have a moral philosophy.