"To use a toaster we have to have already learnt many basic skills and conventions. That it needs a power supply, how to plug it in and into what - what the actual function is - If I was a 'man from Mars" and was told this is a toaster it makes toast - I would look at it and say, perhaps in Martian - OK make toast - I may prod it and I may kick it, but the result would not be toast."