As philosophers speak, they think that there are things whicht they can see and speak about as philosophers. But what are these things? And what is the general character of the philosopher's statements? How can we find out whether they are true? If, as is widely agreed, the philosopher does not rely on empirical research, in which direction ought we to look for the evidence to support philosophieal statements? Husserl's transcendental-phenomenological reduction, we propose to show, can best be understood as an attempt to indicate the nature and direction of the specifically philosophieal concern. The reduction, as he understood it, determines the domain of philosophieal research, the character of philosophical statements, and the direction in which we can look for evidence to support such statements. In this paper we shall concentrate on the Ideas, the work which Husserl published in 1913 as a general introduction to phenomenology.