On Western materialistic rationalism and Behavioral Psychology- Bacon, Hegel, Kant all argue for rationalism as the basis for Man's understanding of the universe. The scientific method becomes the de facto source of truth and knowledge. If you cannot observe the cause and effect first hand in a lab setting it is suspect and irrational. The existence of God falls into this category.

The concept of the rational investor theory was a very popular 20th century theory on equity market behavior. The market knows all, therefore the market is the best indicator of economic current and future outlook. Until it does not- the crashes of the 20's and 2000's attest to this.