Theoretical thinking is a feature of science and there are today many sciences. At school we typically study physics, chemistry and biology; then there are also subjects such as psychology and mathematics. Each of them investigates its own irreducible terrain of reality in which certain properties and laws that form a basic kind of functioning of the objects and events in our experience are grouped together. Mathematicians, for example, focus on numbers themselves, not on counting particular objects, but investigating numerical properties as they can be understood in isolation from the objects of ordinary experience. In biology we investigate generative (living) systems that reproduce and go through cycles of development. In physics the focus is on the interactions of energy that are presupposed in living organisms, but also on physical forces such as gravity and electromagnetism. We can see that theory works by isolating aspects of the world in order to produce explanations [add examples]. This characterises science and cuts across the division of so-called ‘natural’ and ‘social’ sciences. We can also see that the explanations produced give us a model of the world that is different from what we directly perceive. From this we conclude that theoretical thinking has the character of analysis, of identifying and distinguishing things, of taking things apart in thought. In theory we view reality from an abstract perspective such as that of physics; we may start with the fullness of our experience of reality but we find a point of entry that directs us to certain features that are of specific interest. So we might have a flower in front of us and our point of interest is in the psychological benefits of having flowers in a hospital environment, or our point of interest may be in its economic value and role in a particular economy, or we may be interested in the flower from a more strictly biological perspective its processes of growth, maturation, reproduction etc. In each approach there is a human busy in the activity of selecting particular features of an object for further investigation. In this act of thought we leave behind, though only in our thinking and explaining, the fullness of reality as we usually experience it and investigate an isolated part of it.
It takes considerable training to achieve this ability to select a relevant viewpoint to guide our investigation into some matter or other, and yet as a learnt human skill it becomes part of the scientist’s second nature and so easily passes unnoticed. However, if we step back from this activity and ask ourselves how the resulting analysis and explanation relates to the results of other sciences with their different points of interest, and how these in turn relate to the original fullness of reality that we confront in our everyday experience then we face a perplexing philosophical problem of unity and diversity. We can unpack this by asking two distinct questions: How do all these perspectives relate to each other? And then: Can they all be united into a single understanding of reality? But these questions cannot be answered by theoretical thought alone even though it is awakened by them. They are questions that sit on the very boundary of theoretical thought, or we could say at its limits. Here it is appropriate to say that philosophy should proceed with a sense of wonder.
I say so-called ‘natural’ because social sciences such as sociology, economics, history and so on can hardly be said to investigate non-natural aspects of reality. These sciences investigate properties and processes that are just as much part of our world as those studied by the ‘natural’ sciences. It is only a certain kind of philosophical prejudice that elevates the ‘natural’ sciences to a level of ‘real’ or ‘hard’ science as opposed to ‘soft’ sciences. This is another result of reductionist thinking.