However, before we dismiss this type of approach altogether, we should consider some of the things in behaviourisms favour. Wittgenstein, in the Philosophical Investigations, argued that it was impossible to have what is termed a private language. In other words, if you grew up alone on a desert island – I know there would be logistical difficulties, but bear with me for a second – you would not develop an internal language because you have no one to develop an external one with.

This point is an important one. Consider the meaning of everyday words – “red”, “bus”, “clever” – how do we learn what they mean? Wittgenstein would argue that it is through being part of a society of language users. Now, if I refer to myself and my experiences in words that I have learnt through conversation with others, my personal experiences are, in some way, largely public. For example, if I find something funny, I laugh. When I do so, I am using a form of language. My understanding that something is funny, the reactions of others that I call “laughing”, my own laughter, are all part of a public language. So, even when I find something funny and no one else does, I am using a public language to express my behaviour.