On Physics and Other Natural Phenomena

In the opening lines of the second chapter of his novel Leviathan, Hobbes states:

That when a thing lies still, unless somewhat else stir it, it will lie still for ever, is a truth that no man doubts of.  But when a thing is in motion, it will internally be in motion, unless someone else stay it…(7). 

Those of you that are familiar with classical mechanics will notice that what Hobbes describes here is Newton’s First Law of Motion.  If you have yet to encounter Newton’s Laws of Motion (or if you have forgotten what they were), I will quickly recap them here.

There are three fundamental laws of motion, each which describe the motion of an object (or a collective group of objects) when a outside force is applied to it.  These laws are as follows:

  • Newton’s First Law (aka The Law of Inertia): An object will move uniformly (will move with constant speed and direction) unless acted upon by an outside net force.  Eg. A ball that is thrown horizontally will continue to move horizontally–at the same speed and in the same direction as it was thrown– forever unless some outside force (such as gravity or air resistance) acts upon it.
  • Newton’s Second Law: The force (F) on a object is equal to the mass (m) of the object multiplied by its acceleration (a)


Basically, this law states, that if an object does not have a mass (or if the object is not accelerating), then a force cannot be acting on it.

  • Newton’s Third Law: For every action there is an equal and opposite reaction (“Equal and opposite” is short for “equal in magnitude and opposite in direction”).  E.g. When you hit a ball with a racket, the force that the racket exerts on the ball is equal in magnitude and opposite in direction to the force that the ball applies on the racket.  You can observe this effects of this law by pushing on a table with your hand.  You will notice that even though you are pushing on the table, the skin on your hand will be indented where it is touching the table.  This happens because the table is exerting a force back on you!

Returning to Hobbes, one might begin to see how these laws could pertain to Hobbes and his argument.  After all, as Dr. Hendricks pointed out in the lecture and in seminar, to Hobbes:

life is but a motion of limbs,….For what is the heart but a spring; and the nerves, but so many strings; and the joints, but so many wheels, giving motion to the whole body… (3)

Humans are nothing more than automata to Hobbes, “engines that move themselves by springs and wheels” (3), things that act in a predictable and perpetual manner in accordance to Newton’s First Law of Motion.

Yet, Newton’s Second Law is also equally applicable to Hobbes’ argument.  In chapter I, Hobbes states that humans are able to perceive things when they sense them.  Sense, as defined by Hobbes, is the “diversity of appearances” (6) that are produced when an object acts on a person’s body.  He then goes on to say that:

The cause of sense is the external body, or object, which presseth the organ proper to each sense,…which pressure, by the mediation of nerves and other strings and membranes of the body, continued inwards to the brain and heart, causeth there a resistance, or counter-pressure, or endeavour of the heart to deliver itself… (6)

If we refer back to Newton’s Laws of Motion, we see that what Hobbes has described here sounds awfully similar to the Second Law of Motion.  For, in the quote above, there is an external body, or mass, applying a force on another mass (the human body), causing the mass on which this force is applied to accelerate (move).  But, because this force that allows objects to be sensed can only be applied by a mass on another mass, only things with masses can perceive and be perceived.  Furthermore, Hobbes comes to conclude that names such as “incorporeal body” and “incorporeal substance” are “contradictory and inconsistent” (21).  By this reasoning, if one is to accept that God or the soul exists, then they both must be corporeal and have a mass.  However, this means that the Law of Conservation of Mass would then apply to both God and the soul.  The Law of Conservation of Mass states that: mass cannot be created nor destroyed; it can only be rearranged into different forms.  If this is the case, then what happens to your soul when you die? Also, if the human population is continuously growing and matter cannot be created, then how are new people being born?

In seminar, Dr. Hendricks (and I apologize in advance if I get this wrong) said that, later in Leviathan, Hobbes proposes that, immediately after death, nothing happens.  But, eventually, your soul is resurrected in a new body somewhere on Earth.  However, the chapter in which Hobbes argues for this is not within the prescribed reading for Arts One.  Another person in my seminar also said that it could be likely that (and I am sorry if I get this wrong, too) your soul might go to another materialistic place when you die.  As the matter of the soul is not being created nor destroyed in either case, the Law of Conservation of Mass is upheld.  Thus, both of these propositions could occur if the soul was corporeal.

However, I don’t feel like my second question was adequately answered in seminar.  Since we are doing two weeks of Hobbes, I hope that we can reflect on this question and, perhaps, come up an answer for it.  Please feel free to leave a comment even if you aren’t in the Hendricks seminar!

Okay, this is a bit of an aside to what I was talking about previously, but I am going to mention it anyways.  In Chapters XIV and VX, Hobbes prescribes a set of laws, which he refers to as the Laws of Nature.  But, why does Hobbes choose to give these laws this name? After all, when I hear the word “nature”, I think of the way things  are in their natural state.  According to Hobbes, the natural condition of mankind is “a war…of every man against every man” (76).  But, in Chapter XV, Hobbes states that some of his laws of nature “only concern the doctrine of civil society” (99) and, thus, would not apply in the natural state of man, which is confusing.  In seminar, Dr. Hendricks pointed out that Hobbes defines a Law of Nature as a:

precept or general rule, found out by reason, by which a man is forbidden to do that which is destructive of his life or taketh away the means of preserving the same, and to omit that by which he thinketh it may best be preserved” (79)

By definition, Hobbes’ Laws of Nature describe the natural order of the world.  Hence, the Laws of Nature are not like a civil law, which are prescribed by the commonwealth, but are more akin to fundamental laws, such as Newton’s Law of Motion, which describe the way that the world works.  Newton’s Laws of Motion describe what is required for things to move.  Likewise, Hobbes’ Laws of Nature state what needs to occur in order for well functioning groups of people to exist.  Yet, Dr. Hendricks also made it clear that, because people have various different opinions  on what Hobbes means when he refers to the Laws of Nature, there is a lot of scholarship on this matter.  If you think there is another reason why Hobbes calls his laws the Laws of Nature, please consider leaving a comment as well.  I’d love to hear what you have to say about this!