And most important of all, far down and yet always at the surface of his thought, was the problem of how he should comport himself toward these persons.

What should his attitude be?
He wrestled continually and anxiously with the problem.

There were cowardly suggestions that he should make believe, assume a part; and there were still more cowardly suggestions that warned him he would fail in such course, that his nature was not fitted to live up to it, and that he would make a fool of himself.
It was during the first part of the dinner, struggling to decide upon his attitude, that he was very quiet.

He did not know that his quietness was giving the lie to Arthur's words of the day before, when that brother of hers had announced that he was going to bring a wild man home to dinner and for them not to be alarmed, because they would find him an interesting wild man.

Martin Eden could not have found it in him, just then, to believe that her brother could be guilty of such treachery--especially when he had been the means of getting this particular brother out of an unpleasant row.