(75) The "black box" mentality generates misapprehensions

In the past, electronic circuits were constructed by coupling together individual electronic components. Most constructors had a good appreciation of what was going on in those circuits. Now, however, it is increasingly common to use "black box" components that have complex integrated circuits; we use them effectively but only appreciate the input to output functions, without a detailed knowledge of the inner workings. This is analogous to what we do when we encapsulate a complex process in a convenient single word or short phrase. Once we give some process a title (eg, "the immune system" or, my favourite, "a pathogen") we endow it with a potentenial plethora of unwarranted, tacit assumptions. We gain an unjustified faith that we understand "what is in the box?". There tends to be a mass communal adoption of implicit assumptions without emphasising the need to ensure that we occasionally go back to fully comprehend what is, what ought to be and what shouldn't be assumed to be in that "black box". It is important to occasionally reassess the inner workings and to examine the validity of what we assume resides in the box.

This is particularly relevant to our perception of a "pathogen". Nowadays, it is extensively assumed that this term is a synonym for "a pathogenic micro-organism". Our perseption of the body's respnse to invading/proliferating/damaging micro-organisms is distorted by our assumptions of what that "black box" term encapsulates. After all, it seems obvious, doesn't it? Microbes are a threat, they are foreigners, they are damagers. It seems obvious that we need a system specifically dedicated to identifying and attacking them. But step back a bit from this “black box” and consider what is inside it. We've already identified some of the important things about these – so-called – pathogens.

• They are not self cells. However, that can simply mean that they do not have markers characteristic of healthy-self (zygote derived) cells or characteristic markers of their phylogenetic order.
• It can also reflect that they demonstrate properties that were predilections of an amoebocyte’s primordial diet (macrophages are amoebocytic in nature).
• They infiltrate and proliferate in the host. However, they cannot do this without locating a suitable nutrient substrate.
• Part of the fulfilment of this need for nutrients is that they have to promote damage in their host as part of their pursuit for nutrients.
• So let’s unravel the “black box” perception of “pathogens”, and recognise that this title hints that damage is vitally important; that phagocytes have a primordially acquired predilection for microbial "food"; that both characteristic healthy self markers are absent and characterisitc microbial food "signatures" are present.