Discrimination is visible, even statistically measurable in many instances, but the social bias that drives it is often invisible and not directly measurable. Like an underground current, bias is the organising force behind discrimination, whether in hiring, lending or housing. Its effects are seen in a pervasive manner across sectors, but the ways in which bias pulls and tilts visible outcomes remain invisibly obscure.

On the basis of the above passage, the following assumptions have been made:

1. Social bias is the only reason for the existence of discrimination in a society.

2. Discrimination of different kinds reinforces bias.

3. Social bias can be analysed more through its effects than by direct empirical methods.

Which of the above assumptions is/are valid?