Why I'm Indifferent to Men and Women: A Manifesto
Both have an immense capacity for retardation and genius.
Both have an immense capacity for insidiousness and sincerity.
Both have an immense capacity for ugliness and beauty.
Essentialist Philosophy and Ideology that serve Men and damn Women, or serve Women and damn Men are equally faulty in their fragile epistemic and ontic foundations.
Did you intend for your pairings to be opposites (ugliness: beauty; retardation: genius) because insidious is NOT the opposite of sincerity. An insidious disease is a subtly harmful one. If you look at synonyms insidious is closest to stealthy.
Insidious behavior is often characterized by hidden motives, where the individual is more focused on achieving their own goals, rather than being honest and straightforward. They may use deceit, trickery, and manipulation to achieve their aims, often at the expense of others. This type of behavior is often associated with people who are untrustworthy, and can be harmful to both individuals and groups.
Sincerity, on the other hand, is characterized by being honest, open, and genuine in one's actions and words. People who are sincere are often seen as trustworthy and dependable, as they are not motivated by hidden agendas, but rather by a desire to be truthful and authentic. This type of behavior is often associated with people who genuinely care about the well-being of others.
Both insidiousness and sincerity can be viewed as ways of behaving that have a gradual impact on those around them, whether it be negative or positive.