By dissolving that barrier we also enable ourselves to include within science many aspects of the human condition which were previously excluded as subjective. We will look here at this extension to scientific thinking, and how it allows us to apply scientific concepts to the complex processes of mind and behaviour. If we are to avoid disagreement about what constitutes truth then there must be a criterion that does not depend upon personal opinion. Yet even here we cannot exclude subjective issues. The very words 'Rhino' and 'horn' are ill-defined, and can only be regarded as meaningful on the basis of a consensus social definition.
Objectivity is thus no more than consensus subjectivity based upon a human viewpoint.
What is regarded as truth for humans may not be valid for other creatures or for alien lifeforms which can receive very different sense data. Truth thus relates to a viewpoint which is species dependent. It relates to the abilities that we have to classify the world, both sensual and mechanical. No truth can be expected to include all aspects of the subject, since our limitations and desires necessarily must select out those aspects to be measured. What is objective and agreed depends as much on the number of people interested in the subject as it does on the possible attributes available to be measured.