No living being can think without knowing a language.
Whenever we think about something, we are merely having a conversation with ourselves. Conversation is a form of communication. The only way to communicate is through some sort of protocol which both communicating parties must understand. In this case, both parties are the same person and the protocol for communication is a language. More specifically, the language must not contain any basis in the physical world for it must have the ability to be carried out solely in the mind. The only way this is possible is via a natural language.
When we communicate with ourselves, we are carrying out a protocol using a series of words (commonly known to us simply as a “language”). Thinking is the process by which a series of thoughts are combined in a stream. A thought is the most basic unit of thinking, it is composed of a series of words in a stream. If we were to draw a sort of “linguistic class diagram” it would look something like this: Thinking –A-> Thought –B-> Words. The link A is what we subconsciously do when we think. The link B is consciously done by the use of a language.
It is impossible to think without communicating with ourselves and it is impossible to communicate without a language therefore it is impossible to think without a language. The only language which can be processed within our mind is a language containing words. One must be careful to not confuse “thought” with “imagination”.
If I ask you to think about a red elephant for example, you can maybe imagine and visualize this elephant without thinking about it. But if I asked you to think about what the last thing is your mother said to you, you will unavoidably start communicating with yourself by way of a language of words. Ergo, you are thinking by using a language. I want to stress that the kind of thinking I’m talking about is not reflex or instinct, but more of an internal reflection if you will. This can be anything from making a simple decision to thinking about a math problem. You are undoubtably going to speak to yourself in a language of words when you think about something. Perhaps this can more easily be proven by showing you that it’s impossible to think without speaking a language (whether it be orally or in your mind). As an experiment, close your eyes and think of something. Can you do it without speaking in a language? If your head is completely void of words, you are not thinking. The only way you can think is by way of speaking to yourself and the only way to speak to yourself is by way of a language.
Corollary 7.1. Regarding intelligence.
It’s not hard now to imagine that the more words you know, the more elaborately you can think about something. Furthermore, the more elaborately you can think about something, the more knowledgeable you are regarding that topic. One might even say that the more knowledgeable you are, the more intelligent you are, but these are fragile grounds and I won’t venture off there any further. Can there then be a link between knowledge of a language and intelligence? It is certainly true that the more intellectual people have a much more vast repertoire of words at their disposal.
Corollary 7.2 Regarding animals.
Another consequence of the theorem is that it makes it obvious that most animals can’t think. Most animals live by instinct and reflexes. I argue that this is because they haven’t the capacity required to create a language. The reason for this might be the limit in their ability to communicate with their “peers”, if you will. A dog can howl, bark and whine, that’s about it. Its thinking is therefore limited to these three “words”. They can react when they are called, they can obey commands but they don’t reflect on them like we do, they don’t “think”. It would be interesting to see why intelligent animals like dolphins and chimpanzees seem to have the ability to think. Chimpanzees, and in fact most primates, have the ability to communicate through sign language. Sign language, however, makes it very difficult, if not impossible, to communicate within the mind. I will regard this objection as false and say that primitive primates think by visualizing sign language in their head. Dolphins are an exceptional case and worth thinking about. I have yet to find an answer for this that holds with the theorem. Dolphins are a mysterious exception and contradiction to this theorem and have a unique ability to think when others cannot (much like philosophers). Most of the time it is physical attributes that limit the ability to communicate. For one to be able to communicate with himself, he must be able to communicate with others, otherwise the concept of a language is incomplete.