This question asks to identify the philosopher whose philosophy is characterized by three specific forms of naturalism: Social, Psychological, and Physical.

Understanding Rousseau's Philosophical Naturalism

The philosophy that aligns with the description of encompassing Social, Psychological, and Physical naturalism is that of Jean-Jacques Rousseau. Rousseau was an influential Enlightenment thinker whose ideas profoundly impacted political thought, education, and social theory.

Analyzing the Forms of Naturalism in Rousseau's Work

Rousseau's philosophy emphasizes the importance of nature and the natural state of humanity. This emphasis can be seen across the three forms mentioned:

• Social Naturalism: Rousseau explored how society should be structured based on natural principles. In his work The Social Contract, he discusses the formation of a legitimate political order derived from the consent of the governed, reflecting a view that social structures can and should align with natural foundations and the 'general will' of the people. He believed that humans are naturally inclined towards cooperation but are corrupted by society.
• Psychological Naturalism: Rousseau's treatise Emile, or On Education is a cornerstone of this aspect. He argued that children are born inherently good and that their psychological development should follow a natural progression, free from the corrupting influences of society. Education, for Rousseau, should nurture the innate qualities and potential of the individual according to their natural stage of development.
• Physical Naturalism: This relates to Rousseau's view of humans as part of the natural world. He often contrasted the artificiality of civilization with the purity and simplicity of nature. His philosophy suggests that the physical environment and humanity's relationship with it are crucial elements in understanding human existence and well-being. He believed that nature provides the best model for living.

Comparing with Other Philosophers

While philosophers like Plato, Locke, and Bertrand Russell were also significant thinkers, their core philosophical systems are not typically categorized by this specific triad of Social, Psychological, and Physical naturalism in the way Rousseau's is:

• Plato focused on idealism and the world of Forms, emphasizing reason and the soul.
• John Locke, an empiricist, focused on natural rights, government, and the mind as a 'tabula rasa' (blank slate).
• Bertrand Russell was a prominent figure in analytic philosophy, logic, and epistemology, known for his logical analyses and empiricism.

Rousseau's distinct focus on the inherent goodness of man, the corrupting influence of society, and the importance of natural education and social organization makes his philosophy particularly suited to the description provided.

Conclusion

Therefore, Rousseau's philosophy is the one that most directly manifests in the three forms of naturalism mentioned: Social, Psychological, and Physical.