"All the more so" is a commonly used phrase in English to emphasize a certain point or argument. However, there are several other synonymous phrases that can be used to convey the same meaning. Some of these include "even more so," "especially," "particularly," "moreover," "furthermore," and "in addition." These phrases are often used in academic and professional settings to convey a strong sense of conviction and emphasis. Using synonyms for "all the more so" can add variety and depth to your language, making your arguments more persuasive and effective.