Final answer:
Douglass claims that the Fourth of July exposes the harsh reality faced by American slaves, using causal reasoning to argue that the celebration of freedom highlights the contradiction between the ideals and the experiences of enslaved people.
Step-by-step explanation:
The claim made by Douglass is that the Fourth of July is a day that exposes the harsh reality and injustice faced by American slaves. This claim can be classified as causal reasoning, as it suggests a cause and effect relationship between the Fourth of July and the revelation of the slaves' situation. Douglass argues that the Fourth of July serves as a stark reminder of the stark contrast between the ideals celebrated on this day and the lived experiences of enslaved individuals.