Galileo on Secondary Qualities of the Matter

Is heat a quality of the matter which we feel when it is heated or it is in a sensation of a body? In The Assayer, Galileo starts with the proposition “Motion is the cause of heat”. So, he wants to undermine a commonly held conception that heat is a quality which resides in the […]

Bacon’s Idols of the Mind

Sir Francis Bacon (1561–1626) was a successful English lawyer, politician, scientist, orator and philosopher. His works were enormously influential during a scientific revolution, in which Bacon proposed a great reformation of all process of knowledge. He popularized a scientific knowledge, often called the Baconian method, based only upon inductive and careful observation of events in […]

Locke on Time

In the Essay Concerning Human Understanding, Locke explains how we come out with ideas of duration, eternity and time.   We receive ideas of duration and measures of it from reflection and sensation, two foundations of knowledge. First, we observe how our ideas are formed in our minds: some begin to appear, others vanish. So, […]

Locke on Active and Passive Power

According to Locke, power is two-fold. Active power is able to make any change, while passive power is able to be changed. For example, fire has a power to meld gold, while gold has a power to be melted. Similarly, the sun has a power to blanch wax, while wax is able to be blanched […]

Locke on Liberty

For Locke, the idea of liberty arises from the power of the mind over the actions of the man. Freedom consists in our being able to act or not act, according as we shall choose or will. Locke gives an example of a man who is carried and locked into a room while asleep. When […]

Locke on Personal Identity

In the chapter XXVII of the Essay Concerning Human Understanding, Locke reflects on what identity consists in. He starts with identity of substances which can be divided into three sorts: God, finite intelligences and bodies. God’s identity cannot be questionable as he is eternal, unalterable and everywhere. Identity of finite intelligences is defined by relation […]

Locke on Simple and Complex Ideas

For Locke, men do not have native ideas. Our minds are furnished with ideas either through perception of external sensible objects or through the internal operations of our minds, perceived and reflected on by ourselves. So, sensation and reflection are two fountains of knowledge from which come all the ideas such as whiteness, sweetness, thinking, […]

Locke on Essence

Locke distinguishes the real essence from the nominal one. The real essence is some unknown insensible constitution of things on which their sensible qualities depend. In other words, it is a foundation from which all properties of things flow. For instance, the real essence of a gold ring is a constitution of its parts, on […]

Locke on Primary and Secondary Qualities

For Locke, idea is the immediate object of perception or whatever the mind perceives in itself. The power to produce any idea in our mind is a quality of the object endowed with that power. For example, a snowball has the power to produce in our minds the ideas of white, cold, and round. It […]

Locke on Solidity

According to John Locke, solidity is an idea that we receive by our touch. It is the most constant idea obtained from sensation. For instance, a moving or resting man always feels something under him that supports him. The floor resists to the entrance of man’s body into the place the floor possesses. When staying […]