What is actually true of being alive, stated as plainly as a proof. Start from a few definitions, take nothing on trust, and follow each step from the ones before it, the way Euclid builds the Elements and the way Spinoza builds the Ethics.
Elements I.1. Two circles, each passing through the other’s centre, and a triangle that could not be otherwise. Spinoza set out to treat human life in “exactly the same manner, as though I were concerned with lines, planes, and solids.” Part III, Preface
Why geometry
Because facts about a life should be checkable.
Most talk about how to live rests on taste, tradition or temperament. Euclid found a way to say things that do not depend on any of them: define your terms, state what you assume, and let each claim rest only on what came before. A triangle’s angles do not care who is reading. Spinoza saw that the same discipline could be applied to people: to fear, hope, love, freedom and death.
Spinoza’s own example: it follows from the nature of a triangle, “from eternity and for eternity, that its three interior angles are equal to two right angles” Part I, Prop. 17, note Nothing about your existence needs to be believed on authority. Every step on this page can be traced, and each proposition links to the passage it comes from.
The conclusionUnderstand what moves you, and your life becomes your own.
Book one
Definitions. Nine words, fixed.
Everything else depends on these, so each is stated once and used the same way throughout.
INature
Everything that exists, together with the laws by which it exists and changes. Spinoza’s name for it is “the eternal and infinite Being, which we call God or Nature”, and he means one reality, not a person above it.Part IV, Preface
IICause
That from which something follows. To explain a thing is to give its causes.Part I, Axiom 3
IIINecessity
What could not have been otherwise, given its causes. Not force from outside: the way a triangle has three sides.Part I, Definition 7
IVFreedom
Not escape from causes, which is impossible. Acting from your own nature and understanding, and not from causes you do not see. “That thing is called free, which exists solely by the necessity of its own nature, and of which the action is determined by itself alone.”Part I, Definition 7
VA human being
A finite part of Nature: one particular body, and the mind that is the idea of that body.Part II
VIStriving
The effort of each thing to go on being what it is. Spinoza’s word is conatus. In a person, with awareness, it is called desire.Part III, Prop. 6
VIIFeeling
A change in your body’s power to act, together with the idea of that change. Joy raises the power, sadness lowers it.Part III, Definition 3
VIIIUnderstanding
Knowing a thing through its causes. The only kind of idea that is fully yours.Part III, Definition 1
IXEternity
Not endless time. The kind of existence a truth has: necessary, and outside before and after.Part I, Definition 8
Book two
Axioms. Euclid’s moves, used on a life.
Six of Euclid’s own moves, with what each secures in geometry and the same thing in human existence.
Euclid
In geometry
In a human life
Common Notion 5: the whole is greater than the part.
No part can contain, command or outlast the whole it belongs to.
You are a part of Nature. The weather, the market, illness and other people are bigger than you, and nothing you believe changes that.
Common Notion 1: things equal to the same thing are equal to each other.
Two descriptions of one thing cannot disagree about it.
Mind and body are each the same individual, described in two languages. A state of one is a state of the other.
Postulate 1: a straight line can be drawn between any two points.
There are no gaps: any two points are joined.
There are no gaps in causation either. Every event is joined to what produced it, however far back you must go to find it.
Proposition I.1: from two circles, an equilateral triangle.
A structure that must exist follows from nothing but a few simple givens.
From a few plain definitions, a whole account of a life follows, and you can check each step.
Proposition I.32: the angles of a triangle equal two right angles.
A truth that holds whether or not anyone believes it or likes it.
The facts about your existence hold the same way. They are not opinions, and you need not accept them for them to be so.
Proof by contradiction: suppose it false and see what breaks.
Shows a thing cannot be otherwise by showing what would follow if it were.
Imagine you were outside Nature, or uncaused, or never finite. Every such picture collapses the moment you work it out.
Euclid’s statements are paraphrased. The Elements course has each one set out with its proof.
Book three
Propositions. Ten facts, each proved.
Each proposition rests only on the definitions and on the propositions before it. The map shows how they hang together.
Follow any line back to the definitions. Select a circle to jump to that proposition.
I
Proposition I
You are inside Nature.
Whatever exists exists within Nature, and you are no exception.
Demonstration
Nature is everything that exists.Def. I
You exist, and you are a particular part of what exists.Def. V
Nothing can exist or be understood outside of Nature, so you are within it.E1p15
You were not placed here from elsewhere. You are made of the same stuff, and obey the same laws, as storms and stars.Hence
Q.E.D.
In Spinoza’s words
“Whatsoever is, is in God, and without God nothing can be, or be conceived.” Part I, Prop. 15
“It is impossible, that man should not be a part of Nature” Part IV, Prop. 4
Scholium: in a human life
The sense of being a stranger who was dropped into the world does not describe your situation. You cannot leave Nature. You can only change within it.
II
Proposition II
Nothing is uncaused.
Everything that happens, including you, happens from causes, and could not have happened otherwise given them.
Demonstration
From a given cause an effect follows.Axiom 1
All things are in Nature, and Nature does not choose or gamble.Prop. I
So every event, including your birth, body, temperament and circumstances, has sufficient causes.Def. II, Def. III
What we call chance is the name we give to causes we have not found.Hence
Q.E.D.
In Spinoza’s words
“Nothing in the universe is contingent, but all things are conditioned to exist and operate in a particular manner by the necessity of the divine nature.” Part I, Prop. 29
Scholium: in a human life
Blame and regret assume things could have gone otherwise with everything else the same. They could not. This is not fatalism, because your present understanding and effort are causes too.
III
Proposition III
You are finite, and surpassed.
Your power is limited and always exceeded by the power of external things.
Demonstration
You are a finite part of Nature.Def. V, Prop. I
For anything finite there is something stronger that can destroy it.Part IV, Axiom
So your force is limited and infinitely surpassed by the power of outside causes.E4p3
Pain, loss, sickness, ageing and death come to everyone, and are consequences of being a part, not punishments.Hence
Q.E.D.
In Spinoza’s words
“There is no individual thing in nature, than which there is not another more powerful and strong.” Part IV, Axiom
“The force whereby a man persists in existing is limited, and is infinitely surpassed by the power of external causes.” Part IV, Prop. 3
Scholium: in a human life
Fragility is the structure of the thing, not a malfunction of it. You cannot win this argument, but you can stop taking it personally.
IV
Proposition IV
Mind and body are one.
The mind and the body are one and the same thing, understood through two different descriptions.
Demonstration
The order of ideas is the same as the order of things.E2p7
Your mind is the idea of your body.Def. V
So whatever happens in the body is expressed in the mind, and the reverse.Notion 1 above
There is no chamber of pure thought, and no body without an inner side.Hence
Q.E.D.
In Spinoza’s words
“The order and connection of ideas is the same as the order and connection of things.” Part II, Prop. 7
Sleep, food, movement and company are not side issues to your thinking. A mood is a bodily state, and a thought is a bodily event.
V
Proposition V
You are striving.
Each thing strives to persist in its being, and that striving is its actual essence. In you, it is desire.
Demonstration
There is no cause from whose nature some effect does not follow. Everything that is, acts.E1p36
Nothing in a thing’s own nature can work to destroy it.Prop. I
So each thing strives, as far as it is in itself, to go on existing.Def. VI
That striving is not something the thing has. It is what the thing is. When it is conscious of itself, it is called desire.E3p7
Q.E.D.
In Spinoza’s words
“The endeavour, wherewith everything endeavours to persist in its own being, is nothing else but the actual essence of the thing in question.” Part III, Prop. 7
“we deem a thing to be good, because we strive for it, wish for it, long for it, or desire it.” Part III, Prop. 9, note
Scholium: in a human life
We do not want things because they are good. We call things good because we want them. Self-knowledge starts with finding out what you actually strive for.
VI
Proposition VI
Feeling is the ledger.
Every feeling reports on your power: joy is that power rising, sadness is that power falling.
Demonstration
You are a striving, and striving has more or less power.Prop. V
What raises or lowers the power of the body raises or lowers the power of the mind, since they are one.Prop. IV, E3p11
That change, felt, is joy when the power rises and sadness when it falls.Def. VII
Every other feeling, from love to envy, is built from desire, joy and sadness together with their causes.Hence
Q.E.D.
In Spinoza’s words
“Whatsoever increases or diminishes, helps or hinders the power of activity in our body, the idea thereof increases or diminishes, helps or hinders the power of thought in our mind.” Part III, Prop. 11
A feeling is information before it is a verdict. Asking whether something makes you more alive or less is an honest first test of whether it is good for you. See all forty-eight in Spinoza’s Mirror.
VII
Proposition VII
You are less free than you feel.
Most of the time you are moved by causes you do not see, and you take the feeling of choosing for freedom.
Demonstration
You are a finite part, so you can never be the sole cause of what happens in you.Prop. III, E4p4
Where you are only a partial cause, you are acted on. That is a passion.Def. II
So you are bound to undergo passions, and outside causes will often rule you.Hence
You feel free because you are aware of your actions and unaware of what caused them.E2p35
Q.E.D.
In Spinoza’s words
“men are mistaken in thinking themselves free; their opinion is made up of consciousness of their own actions, and ignorance of the causes by which they are conditioned.” Part II, Prop. 35, note
“like waves of the sea driven by contrary winds we toss to and fro unwitting of the issue and of our fate.” Part III, Prop. 59, note
Scholium: in a human life
The feeling of free will is real. The explanation for it is mistaken. That is useful, because what is caused by ignorance can be loosened by knowledge.
VIII
Proposition VIII
Understanding loosens the grip.
Knowing the cause of a passion turns it, by degrees, into something you do rather than something done to you.
Demonstration
A feeling is an idea of a change in the body.Def. VII
A vague idea of a feeling is passive. A clear idea of it, with its causes, is your own mind’s action.Def. VIII
So when you form a clear idea of a passion, it ceases to be a passion.E5p3
Understanding also sees that things had to be as they were. That takes the sting out of blame, regret and dread.Prop. II, E5p6
A feeling is conquered only by a stronger feeling, and understanding brings its own joy.E4p7
Q.E.D.
In Spinoza’s words
“An emotion, which is a passion, ceases to be a passion, as soon as we form a clear and distinct idea thereof.” Part V, Prop. 3
“The mind has greater power over the emotions and is less subject thereto, in so far as it understands all things as necessary.” Part V, Prop. 6
“An emotion can only be controlled or destroyed by another emotion contrary thereto, and with more power for controlling emotion.” Part IV, Prop. 7
Scholium: in a human life
This is the whole method, and the only freedom on offer: not to be free of causes, but to act from ones you understand. You can start on the feeling that has hold of you right now. The sixty-second practice shows how.
IX
Proposition IX
Other people.
Nothing is more useful to a human being than a human being who lives by reason, and people’s hatred is best answered without hatred.
Demonstration
What is most useful to you is what most agrees with your nature.Prop. V
What agrees most with a human nature is another human acting from understanding.Prop. VIII
People who live by understanding therefore strengthen one another, and do not compete for the same scarce thing.Hence
Hatred is a sadness, and sadness answered with sadness grows. Only a stronger, opposite feeling undoes it.Prop. VI, E4p7
Q.E.D.
In Spinoza’s words
“There is no individual thing in nature, which is more useful to man, than a man who lives in obedience to reason.” Part IV, Prop. 35, corollary
“He, who lives under the guidance of reason, endeavours, as far as possible, to render back love, or kindness, for other men's hatred, anger, contempt, &c. towards him.” Part IV, Prop. 46
Scholium: in a human life
Choose the people, and build the institutions, that raise understanding. Answering hatred with steadiness is not weakness. It is the only move that does not add to the harm.
X
Proposition X
Death, and what remains.
The body and everything you imagine and remember will end. The truth of what you were, as understood, does not.
Demonstration
The mind is the idea of the body, and the body endures for a time.Def. V, Prop. IV
So imagination and memory last only as long as the body does.E5p21
But the idea of the essence of your body is necessarily in Nature’s order of truths, and that is not a thing in time.Def. IX
So something of the mind remains: the part that understands, not the part that remembers.E5p23
Q.E.D.
In Spinoza’s words
“The mind can only imagine anything, or remember what is past, while the body endures.” Part V, Prop. 21
“The human mind cannot be absolutely destroyed with the body, but there remains of it something which is eternal.” Part V, Prop. 23
“A free man thinks of death least of all things; and his wisdom is a meditation not of death but of life.” Part IV, Prop. 67
Scholium: in a human life
This is not a promise that you carry on as a person, and readers still argue about exactly what Spinoza means. It means that what you understand becomes, in a real sense, permanent. So spend the time you have on life and not on dread.
The conclusion
What follows from all of it.
Blessedness is not a reward you earn later for having lived well. It is what understanding feels like, and so it is available now, in whatever measure you understand. “Blessedness is not the reward of virtue, but virtue itself” Part V, Prop. 42
Q.E.D.
Corollaries
Six things that follow for living.
1
Trade blame for cause.
Whenever you catch yourself saying “should have”, find the causes instead. It tells you more, and it hurts less.
Prop. II
2
Start with the body.
Sleep, food, movement and daylight belong to your thinking, not to a separate department called health.
Prop. IV
3
Notice which way the needle moves.
After any person, habit or purchase, ask whether your power to act is up or down. Keep what lifts it.
Prop. VI
4
Name what has hold of you.
Put the feeling into words, then write its causes. A clear idea is the beginning of freedom.
Prop. VIII
5
Seek concord, and answer hatred steadily.
Invest in people who make you understand more. Decline to return contempt with contempt.
Prop. IX
6
Think about living.
Accept that the end is coming, then use the time on what raises your power and other people’s.
Prop. X
Scholium
What does not follow.
Four conclusions people draw from the above that the proofs do not support.
“So nothing matters.”
It is because your feelings follow from causes that they matter: they are the real measure of your power to act.
“So why try?”
Trying is one of the causes. Understanding and effort are part of what makes the next moment what it is.
“So be selfish.”
Striving for your own good, rightly understood, leads straight to other people, since nothing is more useful to you than people who understand.
“So accept injustice.”
Understanding why an injury happened is not the same as consenting to it. A clear head resists better than an angry one.
Going further
Check the proofs yourself.
Quotations are from the Elwes translation published in the site’s Ethics reader. The demonstrations here are condensed and put in plain words; the full proofs are Spinoza’s. This page is for learning, not a substitute for medical or mental-health care. If you are thinking about harming yourself, please reach a person now: in the US call or text 988, or find a line in your country at findahelpline.com.