 Trust is also crucial for knowledge, given that scientific knowledge (Hardwig 1991), moral knowledge (Jones 1999), and almost all knowledge in fact (Webb 1993) depends for its acquisition on trust in the testimony of others. The basic argument for the need to trust what others say is that no one person has the time, intellect, and experience necessary to independently learn facts about the world that many of us do know. Examples include the scientific fact that the earth is round, the moral fact that the oppression of people from social groups different from our own can be severe (Jones 1999), and the mundane fact that we were born on such-in-such a day (Webb 1993: 261). Of course, trusting the people who testify to these facts could only generate knowledge if the trust was justified. If we were told our date of birth by people who were determined oddly to deceive us about when we were born, then we would not know when we were born.