The phrase "by degrees" is commonly used to indicate slow, gradual progression. Synonyms for this phrase include "gradually," "step by step," "slowly but surely," "little by little," "in increments," and "progressively." Each of these synonyms emphasizes the gradual nature of the process but may bring a slightly different nuance or connotation to the sentence. For example, "step by step" suggests a more deliberate, calculated approach, while "in increments" may imply a more structured, intentional way of progressing. Regardless of the specific synonym used, they all convey the same idea of gradual progression over time.