Simple ideas of sense can be systematically divided according to their source: some come from one sense only, some from more than one sense, some only from reflection, and some from both sensation and reflection.

By John Locke, from An Essay Concerning Human Understanding

Key Arguments

  • Locke introduces a fourfold division 'in reference to the different ways whereby they make their approaches to our minds, and make themselves perceivable by us', organizing simple ideas by the manner in which they enter the mind.
  • He explicitly distinguishes: 'First, then, There are some which come into our minds by one sense only. Secondly, There are others that convey themselves into the mind by more senses than one. Thirdly, Others that are had from reflection only. Fourthly, There are some that make themselves way, and are suggested to the mind by all the ways of sensation and reflection.'
  • He announces a plan of treatment—'We shall consider them apart under these several heads.'—showing that this division is methodologically central to his subsequent analysis of simple ideas.

Source Quotes

Division of simple ideas. The better to conceive the ideas we receive from sensation, it may not be amiss for us to consider them, in reference to the different ways whereby they make their approaches to our minds, and make themselves perceivable by us. First, then, There are some which come into our minds by one sense only.
The better to conceive the ideas we receive from sensation, it may not be amiss for us to consider them, in reference to the different ways whereby they make their approaches to our minds, and make themselves perceivable by us. First, then, There are some which come into our minds by one sense only. Secondly, There are others that convey themselves into the mind by more senses than one. Thirdly, Others that are had from reflection only. Fourthly, There are some that make themselves way, and are suggested to the mind by all the ways of sensation and reflection. We shall consider them apart under these several heads.
Fourthly, There are some that make themselves way, and are suggested to the mind by all the ways of sensation and reflection. We shall consider them apart under these several heads. Ideas of one sense.

Key Concepts

  • The better to conceive the ideas we receive from sensation, it may not be amiss for us to consider them, in reference to the different ways whereby they make their approaches to our minds, and make themselves perceivable by us.
  • First, then, There are some which come into our minds by one sense only. Secondly, There are others that convey themselves into the mind by more senses than one. Thirdly, Others that are had from reflection only. Fourthly, There are some that make themselves way, and are suggested to the mind by all the ways of sensation and reflection.
  • We shall consider them apart under these several heads.

Context

Book II, chapter III ('Of Simple Ideas Of Sense'), opening of section 1, where Locke proposes a fourfold classification of simple ideas by the mode of their entry into the mind, setting the agenda for the chapter.