Lesson 17: The Role of the Intellect and Sensation in Ideas

The Fundamentality of the Intellect or Sensation for Ideas

As we have mentioned, Western philosophers may be divided into two groups with regard to the explanation of the appearance of ideas.

One group believes that the intellect perceives a series of concepts without need for sensation, like Descartes believed with regard to the concepts of God and soul, from among the immaterial things, and length and shape from among the material things. He calls these kinds of qualities of materials which are not perceived directly from sensation ‘primary qualities’.

To the contrary, he called qualities such as color, smell and taste, which are perceived by sensation ‘secondary qualities’. In this way he believed in a kind of priority of the intellect. He considered the perception of secondary qualities which are obtained by means of the senses to be fallible and unreliable. In this way, he proved another kind of priority of the intellect, which is related to the discussion of the value of knowledge.

Likewise, Kant related a series of concepts called ‘a priori’ to the mind. From among them he related the concepts of space and time to the levels of sensation, and he related the twelve categories to the level of understanding. He considered the understanding of these concepts to be essential innate qualities of the mind.

The other group believes that the mind of man is created like a blank slate, with no engraving on it, and that contact with external existents by means of the sense organs causes the appearance of images and engravings on it. In this way various perceptions occur. Epicures are reported to have said, “There is nothing in the intellect unless it has previously been in sensation.” The very same phrase was repeated by John Locke, the English empiricist.

However, their statements about the appearance of intellectual concepts differ. The apparent meaning of some of them is that sensory perceptions are changed in shape and transformed to intellectual perceptions by the intellect, just as a carpenter cuts pieces of wood to make them into various shapes and build a table, chair, door or window.

So, intellectual concepts are the very sensory forms whose shapes have been changed. The statements of some others may be interpreted to mean that sensory perceptions provide the grounds and capital for intellectual perceptions, although this is not to say that sensory forms are really changed to intellectual concepts.

The Table of the Categories

Judgment Category Example
Quantity Universal Unity All men are mortal.
Particular Plurality Some men are philosophers.
Singular Totality Socrates was a sage.
Quality Affirmative Reality Man is mortal.
Negative Negation The spirit is not mortal.
Infinite Limitation The spirit is non-material.
Relation Categorical Of inherence and subsistence God is just.
Hypothetical Of causality and dependence If God is just to people, He will give rewards and punishments.
Disjunctive Of community Byzantium was the greatest nation of ancient Europe.
Modality Problematical Possibility—Impossibility Some planets may have living things on them.
Assertorical Existence—
The earth is round.
Apodeictical Necessity—
God is necessarily just.

We mentioned previously that extreme empiricist, such as the positivists, basically deny the existence of intellectual concepts, and they interpret them as forms of mental words.

Some empiricists, such as the French Condiac, limit experiences which cause the appearance of mental concepts to sense experience. Others, such as the English John Locke, extend them to inner experiences. Among them Berkeley has an exceptional position, and he limits experiences to inner experience, for he denies the existence of material things. On this basis, sensory experience is not possible.

We must add that most empiricists, especially those who accept internal experiences, do not limit the realm of knowledge to the material, and they prove metaphysical matters by the intellect. Although, according to the doctrine of the fundamentality of sensation, and the complete dependence of mental conceptions on sensory conception, such belief is not very logical. The denial of metaphysics is also without reason. Because of this, Hume, who had noticed this point, considered cases which cannot be directly experienced as dubious.

It is clear that extensive detailed criticism of both tendencies would require a separate and weighty text, so that the statements of each thinker could be reported and examined, but this work is not appropriate in this book. Hence, it suffices to briefly criticize their basic ideas without regard to the particular features of each position.


1. It is not acceptable to assume that from the beginning of its existence the intellect has specific concepts, and that it is mixed with them, or that after a while it understands them automatically and without the effect of any other factor. The conscience of every aware human being denies this, whether the assumed concepts are related to the material or related to the abstract, or whether it accords with both areas.

2. Supposing that a series of concepts are necessary for the nature and constitution of the intellect, it cannot be proved that they represent reality, and at most it can be said that a certain subject is accepted by the nature of the intellect, and it is probable that if the intellect had been created in another form, it would have perceived objects in other ways.

To compensate for this deficiency, Descartes grasped hold of divine wisdom. He said that if God had placed these concepts in the nature of the intellect, contrary to reality and truth, he necessarily would have been a deceiver. However, it is clear that the attributes of Almighty God, and His lack of deception must be proved by intellectual reasons. But if intellectual perceptions are not correct the basis of this argument collapses. The guarantee of its correctness through this argument is circular.

3. Suppose that intellectual concepts came from a change in sensory forms. This would require that a form which changes and is transformed into an intellectual concept would not retain its original form, however, with the appearance of universal concepts in the mind; concomitantly and simultaneously we see that sensory and imaginary forms retain their own states. Moreover, it is only material existents which are apt to change, while perceptual forms are abstract, as will be proved in its proper place.

4. Most of the intellectual concepts, such as the concept of cause and effect, do not have sensory or imaginary forms at all, so they cannot be said to come from changes in sensory forms.

5. Suppose that sensory forms provide the stock and ground for intellectual concepts, and that they do not really change into them. Although this is less problematic and closer to the truth [than the previous supposition], and is acceptable with respect to some whatish concepts, nevertheless, it is not proper to limit the grounds of intellectual concepts to sensory perceptions.

For example, it cannot be said that philosophical concepts are obtained from abstraction and generalization of sensory perceptions, because, as has already been pointed out, there does not exist any sensory or imaginal perceptions equivalent to them.

Inquiry into a Problem

In order to become clear about the role of sense and intellect in ideas, we shall take a glance at the types of concepts and the way in which they appear.

When we open our eyes to the beautiful scenery of a garden, the different colors of the flowers and leaves attract our attention. Various perceptual forms are pictured in our minds. When we close our eyes, we no longer see the beautiful dazzling colors, and this is the same sensory perception which vanishes when the relation to the external world is cut. However, we can imagine the same flowers in our mind, and remember that beautiful scenery. This is imaginary perception.

In addition to sensory and imaginary forms which represent specific things, we also perceive a series of universal concepts which do not describe specific things, such as the concepts of green, red, yellow, purple, indigo, etc. Likewise the concept of color itself, which can be applied to various different colors, cannot be considered as the faded and vague form of one of them.

Obviously, if we had not seen the color of the leaves of trees and things of the same color, we could envisage neither imaginary forms nor intellectual concepts of them. So, one who is blind cannot imagine colors and one who has no sense of smell has no concept of the various fragrances. Because of this, it is said, “He who lacks a sense lacks a knowledge,” that is, someone who lacks a sense is deprived of a kind of concept and awareness.

So undoubtedly, the appearance of this kind of universal concept depends on the occurrence of particular perceptions. But this does not mean that sensory perceptions are transformed into intellectual perceptions like wood into a chair, or material to energy, or like a specific kind of energy is transformed into another kind, for, as we have said, this kind of transformation requires that the initial state of the thing transformed does not remain while particular perceptions can remain after the appearance of the intellectual concepts.

Moreover, transformations are basically material, while perceptions are absolutely abstract, as will be proved in its proper place, God willing. Therefore, the role of the senses in the creation of this kind of universal concept is only that of a basis or necessary condition.

There is another group of concepts which has no relation to sensible things, but rather describe psychological states, states which are perceived with presentational knowledge and inner experience, such as the concepts of fear, affection, enmity, pleasure and pain.

Undoubtedly, if we did not have inner feelings, we could never perceive their universal concepts. So, a child cannot understand some adult forms of pleasure until after it reaches maturity, and prior to that it has no specific concept of them. Therefore, this group of concepts is also in need of prior individual perceptions, but not perceptions which are acquired with the help of sensory organs. Therefore, sensory experience has no role in the acquisition of this group of whatish concepts.

On the other hand, we have a series of concepts which have no instances in the external world, and only have instances in the mind, such as the concept “universal”, which corresponds to other mental concepts, and there is nothing outside of the mind which can be called “universal” with the meaning of a concept applicable to numerous individuals.

It is clear that this kind of concept is not obtained by abstraction and generalization from sensory perceptions, although a kind of mental experience is needed, that is, until a series of intellectual concepts is acquired by the mind, we cannot discuss whether they are applicable to numerous individuals or not.

This is the very mental experience which we have indicated. That is, the mind of man has the power to be aware of concepts within itself, and to recognize them just as he does the objects of the external world, and has the power to abstract specific concepts from them. The instances of these abstracted concepts are the same as the primary concepts. This is why these kinds of concepts which are used in logic are called “secondary logical intelligibles”.

Finally, we arrive at another chain of intellectual concepts, which are used in philosophy, from which primary self-evident propositions are formed, and hence, these concepts have great importance. Various opinions have been presented with regard to the formation of these concepts, discussion of which would take too much time, but in the discussion of ontology we shall speak of the conditions for the formation of each of these relevant concepts.

Here we shall only present as much as is necessary. It is to be noted that these concepts, since they are applied to things in the external world, or in technical terms, their characterization (ittisaf) is external, they are like whatish concepts, but since they do not describe specific whatnesses, and in technical terms, their occurrence (‘arudh) is mental, they are like logical concepts. For this reason they are sometimes confused with these two other groups of concepts. This very mistake is made by the great thinkers, especially Western philosophers.

We have already learned that we recognize our own selves and our psychological states or mental forms and actions of the soul, such as our decisions, with presentational knowledge. We now add that man is able to compare each aspect of the self with the self itself, without paying any attention to the whatnesses of either of them, but by paying attention to their existential relations, and finding that the self can exist without any of them.

However, none of them could occur without the self. By attending to this relation it may be judged that each aspect of the soul requires the self, but the self does not require them, but is self-sufficient, needless and independent. On this basis, the mind abstracts the concept of cause from the self and the concept of effect from each of these mentioned aspects.

Clearly, sensory perceptions play no role in the formation of the concepts of need, independence, self-sufficiency, cause and effect. The abstraction of these concepts does not originate with the sensory perception of their instances. Even knowledge by presence and inner experience relating to each of them are not sufficient for the abstraction of the concepts related to them.

Rather, comparison between them is necessary, and the specific relation between them must be taken into consideration, and for this reason it is said that these concepts do not have objective equivalents, although their characterization (ittisaf) is external.

In conclusion, every intellectual concept requires a prior individual perception, a perception which provides the grounds for the abstraction of a concept of a species. This perception, in some cases, is a sensory perception, and in other cases is knowledge by presence and inner intuitions.

Therefore, the role of sensation in the formation of universal concepts is only that of providing the grounds for one group of whatish concepts. It is the intellect that plays the basic role in the formation of all universal concepts.