Final answer:
West Indies merchants justified the slave trade for its economic benefits and sometimes denied any wrongdoing. In contrast, William Wilberforce countered with moral and ethical arguments in Parliament, aiming to abolish the trade. His efforts culminated in the passage of the Slave Trade Act in 1807.
Step-by-step explanation:
West Indies merchants defended the abusive trade practices primarily by justifying economic benefits. They argued that the slave trade was essential to the British economy, providing wealth and jobs. They claimed that without the trade, the economy would suffer. Moreover, they occasionally denied any wrongdoing, suggesting that the conditions and treatment of slaves were not as bad as abolitionists claimed.
In response, William Wilberforce, a prominent abolitionist, campaigned relentlessly in Parliament to end the slave trade, presenting evidence of its brutality and immorality. Wilberforce's response included appeals to moral and humanitarian values, as well as reasoned arguments that a society built on such inhuman practices could not be sustained. His speeches and proposals were intended to elicit a moral awakening and persuade Parliament to pass legislation banning the trade.
Wilberforce likely wanted his response to have the effect of swaying public and parliamentary opinion against the slave trade, leading to legislative action and abolition. By highlighting the moral and ethical issues, he aimed to create a groundswell of support for the movement to end slavery and the associated trade practices, which he ultimately achieved with the passage of the Slave Trade Act in 1807.