So are we doomed to complete subjectivity? The basis of our understanding anything is through the category structures and cognitive models in our minds. These are not hard-wired, but based entirely on our experience of the world through a body. Our experience of the world varies hugely across various cultures, languages and geographies. Not even our bodies are the same, but male differs from female and our bodies have larger or smaller bits, and some of us even have bits missing. How can we ever hope to understand anything another person communicates?
In spite of the variations in our experiences, we all have two things in common.
Firstly, we all have a brain (more or less). If we don’t have a brain then we die. Our brains are quite similar too. Most of us have a cerebral cortex, limbic system, cerebellum etc. and they all have fairly specific roles. The basic architecture is much the same for everyone. This means that our brains work in quite similar ways.
Secondly, we all have a body (more or less). Our bodies may not all have the same bits, but we all have some sort of body. Again, if we don’t have one, we die. Our bodies all come from a roughly similar blue-print, even if there are infinite variations. Having two legs, two arms, a face and hands is fairly common amongst human beings. And having these various appendages shapes the way our brains function because all the input a brain receives, it receives from the body.
These commonalities mean that we all have a few basic concepts that are pretty much the same for everybody. For example, because the vast majority of us have eyes on only one side of our body, we have a concept of back and front. The structure of our eyes, arms and legs means that we are much more easily able to interact with things in front of us. Thus, if I talk about something being in front of me, then you have a pretty good idea of where it is, because we have a common concept of what front means.
There are quite a number of fairly basic categories and concepts that are common to nearly everybody. Because we have a body which can move, and can move other things, we all have a few basic spatial-relation concepts . Another example is in/out. I can walk into a building; or out of a village; or into a garden; or out of a bathroom. Yet another example is paths, roads and passages. Almost all of us move between areas where there is food, areas where we sleep, and areas where we do other things. To get from one place to another I will follow some sort of route. This is another reasonably common concept.*
Interestingly though, we also project these bodily concepts to other things. For example, we don’t just think of people as having fronts and backs. We also attribute fronts and backs to objects like animals, cars, houses and televisions. Animals have eyes, so we attribute them with a front. Buildings often have a main entrance, so we call that side of the building the front.
We even use front and back concepts for things with no front/back-defining features. For example, we say things like ‘I’m in front of the tree’, or ‘she was behind the rock’. The tree or rock only has a front or back in relation to where I am standing. But since we are used to ‘facing’ other human beings, we can talk (and think) as if trees or rocks also had fronts or backs and they are facing us.
We also make metaphorical mappings from bodily concepts to abstract concepts. For example, we commonly talk about emotional states as if they were bounded regions of space. I might say ‘I’m coming out of a depression’, or ’He’s not in a good state’. These mappings are not just linguistic conventions-they are basic building blocks of how we think. We know that emotional states are not really physical locations, but we have no other way of thinking about abstract concepts, except in terms of things we have already experienced.
These projections of bodily concepts onto other things are called conceptual metaphors . These metaphors form the building blocks of most of our reasoning. We build cognitive models of how the world works based on a number of primary metaphors that we learn from a very young age. Primary metaphors are used to build complex metaphors, providing us with mental models of how things work.
The implication of all this, is that all our thinking is related in some way to things we experience with our bodies. Hence the term embodied knowledge. This has some consequences for how we think about what we know, but it also makes communication between human beings possible.
*Actually, the concepts I have described here are made up of conceptual models that are even more basic, but going into all the detail would take too long here. See  for more information.