(The application of a borrowed idea.)
In the philosophy of science, instrumentalism is the view that scientific theories are tools or instruments for predicting and explaining phenomena. Thus, instrumentalism emphasises the practical utility of scientific theories rather than their literal truth. Accordingly, scientific theories do not necessarily provide accurate representations of reality.
This idea does not feature in our day-to-day scientific activities. However, it is an idea about which it is worth being aware. Our descriptions of phenomena are not complete nor entirely accurate. An example of this may be mitosis.
This idea is so central to biology that it seems strange to question its veracity. That cells divide is not open to question. I do question how we describe the process. Biologists are familiar with the four phases of cell division that occur during mitosis:
Prophase - Anaphase - Metaphase - Telophase
Mitosis is something taught from high school on. It can be demonstrated in laboratory classes using the tips of plant roots. It is easy enough to spot, under the microscope, the phases we are required to find. But are there, in fact, four phases?
Cell division was observed first in the eighteenth century. Not until the late nineteenth century was it described in detail. At that time, only fixed and stained tissue sections were available. Today, it is possible to observe living cells during division. Time-lapse videos of mitosis are available. Sped up, these show a more continuous and seamless process. The four phases we learned - and went on to teach - blend into each other. They are not as distinct, clear-cut stages in the overall process.
I am not suggesting that we get rid of these four phases. The classical four phases serve as signposts. They point to the occurrence of specific intracellular changes. Things about which we should be aware. Recognising mitotic features in cells can be important clinically.
However, we should also be aware that how we learn - and teach - colours our perception. When learning about mitosis, it is easy to think that there are just four distinct phases through which cells pass. This perception is reinforced by viewing microscope slides demonstrating each of these phases. We overlook how the four phases of mitosis are an instrumentalist device - a tool.
That other phases need inclusion emphasises this. For example, Prometaphase, Anaphase A, and Anaphase B are three additional phases suggested. Whether they are widely accepted remains to be seen. The four phases are quick and easy to learn. Thinking in terms of these is deeply entrenched in biological thinking. It is unlikely the four phases will ever be replaced.
