Final answer:
Realism holds that there is an external reality, separate from our perceptions, which can be understood through empirical observation. Idealism, while positing that reality is shaped by ideas, does not inherently deny objective truth but suggests it's conceptually constructed. Conversely, anti-realism and moral relativism deny objective moral truths.
Step-by-step explanation:
Idealism and realism are often construed as diametrically opposed philosophies, however, this traditional juxtaposition oversimplifies the relationship between the two. Realism is a doctrine that posits the existence of a reality independent of perception or belief, one that can be understood through empirical observation and rational deduction. It arose in direct response to Romanticism, emphasizing ordinary, everyday subjects, and aiming to depict the “truth” of the world objectively. On the contrary, Idealism posits that reality is constituted by ideas and is mentally constructed; that our concepts and perceptions shape the world we experience. Hence, while anti-realism challenges the notion that there are objective truths, particularly within the realm of ethics, raising concerns about the legitimacy of moral reasoning, Idealism does not necessarily deny the existence of truth but suggests that truth is conceptually constructed.
Moral relativism aligns with anti-realism as it denies objective moral truths, appealing to cultural or individual standpoints instead. Consequently, anti-realists and moral relativists are often critiqued for fostering a skeptical or pessimistic view of resolving moral debates, as in absence of a universal truth, moral claims become arbitrary. This contrasts with moral realism, which posits that moral claims can be true or false based on objective realities, providing a foundation for ethical discourse and practical decision-making within a community.