An Essay Concerning Human Understanding by John Locke - HTML preview

Chapter XXI

Of the Division of the Sciences

1. Science may be divided into three sorts. All that can fall within the compass of human

understanding, being either, First, the nature of things, as they are in themselves, their relations,

and their manner of operation: or, Secondly, that which man himself ought to do, as a rational and

voluntary agent, for the attainment of any end, especially happiness: or, Thirdly, the ways and

means whereby the knowledge of both the one and the other of these is attained and

communicated; I think science may be divided properly into these three sorts:--

2. Physica. First, The knowledge of things, as they are in their own proper beings, their constitution,

properties, and operations; whereby I mean not only matter and body, but spirits also, which have

their proper natures, constitutions, and operations, as well as bodies. This, in a little more enlarged

sense of the word, I call Phusike, or natural philosophy. The end of this is bare speculative truth:

and whatsoever can afford the mind of man any such, falls under this branch, whether it be God

himself, angels, spirits, bodies; or any of their affections, as number, and figure, etc.

3. Practica. Secondly, Praktike, The skill of right applying our own powers and actions, for the

attainment of things good and useful. The most considerable under this head is ethics, which is the

seeking out those rules and measures of human actions, which lead to happiness, and the means to

practise them. The end of this is not bare speculation and the knowledge of truth; but right, and a

conduct suitable to it.

4. Semeiotike. Thirdly, the third branch may be called Semeiotike, or the doctrine of signs; the most

usual whereof being words, it is aptly enough termed also Logike, logic: the business whereof is to

consider the nature of signs, the mind makes use of for the understanding of things, or conveying its

knowledge to others. For, since the things the mind contemplates are none of them, besides itself,

present to the understanding, it is necessary that something else, as a sign or representation of the

thing it considers, should be present to it: and these are ideas. And because the scene of ideas that

makes one man's thoughts cannot be laid open to the immediate view of another, nor laid up

anywhere but in the memory, a no very sure repository: therefore to communicate our thoughts to

one another, as well as record them for our own use, signs of our ideas are also necessary: those

which men have found most convenient, and therefore generally make use of, are articulate sounds.

The consideration, then, of ideas and words as the great instruments of knowledge, makes no

despicable part of their contemplation who would take a view of human knowledge in the whole

extent of it. And perhaps if they were distinctly weighed, and duly considered, they would afford us

another sort of logic and critic, than what we have been hitherto acquainted with.

5. This is the first and most general division of the objects of our understanding. This seems to me

the first and most general, as well as natural division of the objects of our understanding. For a man

can employ his thoughts about nothing, but either, the contemplation of things themselves, for the

discovery of truth; or about the things in his own power, which are his own actions, for the

attainment of his own ends; or the signs the mind makes use of both in the one and the other, and

the right ordering of them, for its clearer information. Al which three, viz., things, as they are in

themselves knowable; actions as they depend on us, in order to happiness; and the right use of

signs in order to knowledge, being toto coelo different, they seemed to me to be the three great

provinces of the intellectual world, wholly separate and distinct one from another.

The End