Kirk, after giving his six canons of conservative thought, turns to cataloging the schools of radicalism and gives a broad outline of their thoughts.  The schools he gives are:

• the rationalist philosophes
• Rousseau‘s romantic emancipation
• Jeremy Bentham‘s utilitarianism
• Auguste Comte‘s positivism
• Marx‘s collective materialism

Their attacks on conservative social order are based on:

• “The perfectibility of man and the illimitable progress of society:  meliorism“
• “Contempt for tradition.  Reason, impulse, and materialistic determinism are severally preferred as guides to social welfare, trustier than the wisdom of our ancestors”
• Political levelling.  Order and privilege are condemned; total democracy, as direct as practicable, is the professed radical ideal”
• Economic levelling.  The ancient rights of property, especially property in land, are suspect to almost all radicals”

Radicals are neoterists.  (The link is to something about post-neoterism, which is more interesting than anything out there about neoterism.)  Change is sought for its own sake.