"They act as if they supposed that to be very sanguine about the general improvement of mankind is a virtue that relieves them from taking trouble about any improvement in particular"

This quote by John Morley is a criticism of those who are excessively positive about the future of humanity, however do not take any action to make that future a reality. He suggests that these individuals act as if their optimism suffices to bring about change, and that they do not require to take any additional action. This is a harmful attitude, as it indicates that no effort is needed to cause the wanted change. Morley is recommending that optimism is not enough, which real effort is needed to cause the wanted improvement. He is encouraging people to take action and not rely entirely on optimism to produce modification. He is highlighting the importance of acting to produce the desired enhancement, instead of just hoping that it will happen.