All good designers work from a philosophy. A design philosophy is a wellspring to which the designer may return to quench a thirst for ideas. It is a place of refreshment and inspiration.
A philosophy of design: We humans are to a large extent a product of our environment. Genetics plays a similar role to environment in personality development. The relative impact of environment on who we are varies from one person to the next as does the balance between environment and genetics.
Our environment, therefore, shapes who we are and what we are able to achieve in life. Architects, landscape architects, civil engineers and others are environmental designers. Designers shape most aspects the human habitat. Environmental designers therefore have a unique ability, and a duty, to understand how an environment affects human development. Those who have the means to shape the human environment also have a responsibility to create environments which allow and encourage positive growth for their families, clients, employees and followers.
A positive human environment begins with basics. Light, air, water, food, activity, interaction, safety, security, comfort, awareness. These healthy elements are similar for all living beings. The proper balance of these elements can contribute to the health, welfare and success in life of the individual and the group. Animals, including humans, respond to an appropriate environment by finding it attractive or even beautiful. Humans crave a positive environment. So, a grounding in, and a periodic review of each of these elements is a must for successful design. The closer a manmade environment is to the ideal habitat, the healthier and better for the human animal.
 Much research has been done on this topic and I will not go into that here except to recommend that an interested or skeptical reader look into the work of Karl Menninger and the Menninger Foundation and their research into the lives of genetically identical twins who were separated at birth.