In The Lagoon, the white man's character is contrasted with that of Arsat, his Malay friend. Conrad is as much a master at presenting the many facets of the white Anglo-Saxon as he is at presenting variances in the native Malay psyche. To that end, Conrad's white man (Tuan) and Arsat typify the ambivalence of cross-cultural male bonding.
‘No, Tuan,’ said Arsat softly. ‘I shall not eat or sleep in this house, but I must first see my road. Now I can see nothing—see nothing! There is no light and no peace in the world; but there is death—death for many. We were sons of the same mother—and I left him the midst of enemies; but I am going back now.’
The white man's response is one of bland resignation; he understands Arsat's plight but does not fully enter into Arsat's sorrow. In other words, the white man likes his friend the way a man values an important tool: necessary in difficult circumstances, but expendable in others.
He liked the man who knew how to keep faith in council and how to fight without fear by the side of his white friend. He liked him—not so much perhaps as a man likes his favorite dog—but still he liked him well enough to help and ask no questions...
Arsat tells Tuan that the Malay and Anglo-Saxon positions are similar; they belong to races who take what they want, when they want it. However, he is under no illusion about Anglo-Saxon fidelity:
'After the time of trouble and war was over and you went away from my country in the pursuit of your desires, which we, men of the islands, cannot understand...'
So, the role of the white man is one of illumination: he represents colonial attitudes toward natives and all the prejudices inherent in the western psyche toward the colonial world. The white man also highlights colonial insensitivity toward typically Malay attitudes and beliefs. His native servants are suspicious and sulky in their chores. They do not relish the idea of getting too near a man like Arsat, even though he is a fellow Malay. After all, his proclamation that "he is not afraid to live amongst the spirits that haunt the places abandoned by mankind," smacks to them of spiritual heresy. Again, the white man's response is one of apathy. It does not touch his well-being and so the matter does not interest him in the least.
White men care not for such things, being unbelievers and in league with the Father of Evil, who leads them unharmed through the invisible dangers of this world. To the warnings of the righteous they oppose an offensive pretence of disbelief. What is there to be done?
Hope this helps. Thanks for the question.