I ended my previous reading of Leviathan with a question:

How does something outside us become something inside us — and how does what becomes inside us eventually determine what we do?

In Chapter 3, Hobbes takes the next step. He has already moved through sense, imagination, memory, dreams, visions and understanding. Now he asks what happens when these thoughts begin to follow one another.

He calls this the “trayne of imaginations.”

Sometimes our thoughts simply wander. One thought brings another, and then another, without any particular destination. A person may remind us of a place, the place of an event, and the event of something completely different. Hobbes says there is no certainty about what we shall imagine next. Such thoughts are unguided, without design and inconstant.

But when desire and design enter, the train of thought becomes regulated.

If we desire something, we think of what we want, then of the means of obtaining it, and perhaps the means to those means, until we arrive at something within our own power to do.

So thought begins to acquire direction:

Desire → aim → means → what is within our power → action.

Hobbes then turns this train backwards through remembrance. If we lose something, we try to remember where we last had it and retrace what we did afterwards. We search backwards through the sequence of our previous thoughts and actions.

But the mind can also travel in the other direction — towards what may happen next.

Hobbes gives the striking example of a crime. The thought of the crime may bring the officer to mind, then prison, the judge and finally the gallows.

None of this has happened yet. The mind is taking what it knows from the past and projecting it into a possible future.

This brings Hobbes to foresight and prudence.

When we repeatedly observe one thing coming before or after another, it becomes a sign. The more often we have observed the relationship, the less uncertain the sign becomes. A person with greater experience therefore has more signs from which to guess what may happen.

But Hobbes is careful here. Prudence is not certainty. He calls it a “Presumption of the Future” contracted from the experience of past time.

We have experienced the past, not the future.

Experience may therefore make our judgement better, but the future remains a conjecture.

Hobbes gives the example of someone who has seen a flourishing state descend into civil war and ruin. If that person later sees the ruins of another state, he may conjecture that something similar happened there. But he cannot know it merely from experience.

This is interesting because Hobbes is showing that we can conjecture in both directions. We can use signs to anticipate an unknown future, but also to reconstruct an unknown past. Both are grounded in experience, and both contain uncertainty.

This is also where his use of prophecy becomes interesting.

Someone who has observed many signs and is particularly good at judging what is likely to follow may appear able to foretell events. But ordinary human foresight still begins with experience. We use what has happened to presume what may happen. More experience may produce better prediction, but it does not turn presumption into certainty.

Hobbes then makes another important point: prudence does not distinguish man from beast. Animals also experience, remember and anticipate. He even observes that some animals at one year old may pursue what is good for them more prudently than a child can at ten.

So where does the difference appear?

Hobbes says that besides sense, thoughts and the train of thoughts, the human mind has no other motion. But with the help of speech and method, these same faculties can be improved to such a height that they distinguish human beings from all other living creatures.

And then, almost immediately after showing how far the human faculties can be developed, Hobbes places an extraordinary limit upon them:

“Whatsoever we imagine, is Finite.”

For me, this is the most revealing part of the chapter.

Hobbes does not mean only that we cannot imagine something infinitely large. He says that no man can have an image of infinite magnitude, infinite swiftness, infinite time, infinite force or infinite power.

We can imagine something larger, faster, longer or more powerful, and then extend it again. But have we actually imagined infinity?

Hobbes says no.

When we call something infinite, he argues, we mean that we cannot conceive its “ends, and bounds”. We do not possess an image of infinity itself. In his striking words, we have no conception of the thing, but of “our own inability.”

I find this a remarkable reversal.

The word infinite appears to tell us something about the thing we are describing. Hobbes makes it also tell us something about the limitation of the mind trying to conceive it.

And his inclusion of infinite force and power matters, because he then takes the argument to God.

We may speak of God’s infinite greatness and power, but Hobbes says this does not mean that we actually conceive infinite greatness or infinite power. God is incomprehensible. His greatness and power are inconceivable to us. The name of God, Hobbes says, is used not to make us conceive Him, but so that we may honour Him.

This seems to reveal where Hobbes has been taking us.

The human mind can travel backwards through remembrance and forwards through foresight. Experience gives us signs from which to judge things we have never directly experienced. Speech and method can develop these faculties to an extraordinary height.

But there are boundaries.

The future can be anticipated, but not made certain by experience. The infinite can be spoken of, but not contained as an image in the human mind.

And perhaps this is why Hobbes ends by attacking the “absurd speeches” of deceived philosophers and the “deceived, or deceiving Schoolmen”.

Words can take us remarkably far. But being able to say something does not necessarily mean that we can conceive what we have said.

So Chapter 3 leaves me with another question:

If our experience allows us to reach beyond the present, and our words allow us to reach beyond what we can imagine, how do we know when we are actually understanding the world — and when we have simply reached the limits of our own mind?