Philosophy had undoubtedly begun to beckon him, although its appealing gesture lacked authority and did not enlist him in any regular course of philosophic studies. In sixty-five he wrote to his brother Henry from Brazil saying, "When I get home, I'm going to study philosophy all my days." But in many respects his character and tastes matured slowly. The instruction offered by Professor Francis Bowen in Harvard College does not appear to have excited his interest at all. It cannot have failed to excite the irony of his father,--as did everything of the sort that was academic and orthodox,--and James would have been aware of this and might have been influenced. On the other hand, it was obvious that, in the case of his father, who had no connection with church, college or school, the consideration and expression of theories and beliefs had always been a totally unremunerative occupation; and James had to consider how to earn a living. His prospective share of the property that had sufficed for his parents was clearly not going to be enough to support him in independent leisure. In the way of bread and butter, biology and medicine offered more than metaphysical speculation. Last and most important, the tide of contemporary inquiry, driven forward by the storm of the Darwinian controversy, was setting strongly toward a fresh examination of nature. Philosophy must embrace the new reality. Everything that was stimulating in contemporary thought urged men to the scrutiny of the phenomenal world. "Natural History," which has since diversified and amplified itself beyond the use of that appellation, was almost romantically "having its day." Grau, teurer Freund, ist alle Theorie, Und grün des Lebens goldener Baum.[29] Thus Goethe, and Louis Agassiz, whose lectures James had already followed, and with the abundance of whose inspiring activity no other scientific energizing could then compare, was fond of quoting the lines. Under such circumstances it was not strange that James should interrupt his medical studies in order to join the expedition which Agassiz was preparing to lead to the Amazon.