“The eyes, chico. They never lie.”

Why human perception is incapable of error.

Tony Montana in Scarface is an uncommonly philosophical gangster.

The idea that our senses cannot be trusted as valid perceivers of reality contaminates every element of contemporary philosophy. The attack on the senses is intended to support the notion that reality and logic are opposites, as seen in the famous analytic-synthetic dichotomy. Thankfully, the leading Objectivist philosopher, Dr Harry Binswanger, has cast the clear light of reason on this issue in his book How We Know, and addressed the question more directly in a recent video titled: “The Innerancy of Perception”.

Here is my summary:

Definition of Perception: “The ongoing awareness of entities in their relative positions gained from actively acquired sensory inputs.”*

*Smell is the only human sense that has no positional element.

Binswanger argues that the senses are not merely valid, but rather serve as the axioms of validity, and are therefore beyond the concept. Like the axioms of logic, sense-data is irrefutable. He likens the claim that sense perception is “valid” to saying “The Constitution is legal”. In this comparison the Constitution is not an aspect of the law, but the standard of legality.

Harry Binswanger

Three arguments against the senses, and the answers:

1. Hallucinations

The claim posits that experiences like hallucinations, where one perceives non-existent entities (e.g., seeing imaginary ants on one's arm under the influence of LSD), cast doubt on the reliability of the senses.

Binswanger's Response:

Hallucinations are internal experiences, not external perceptions. They are the brain's creations, devoid of external reality, thus differentiating them from the direct contact with reality that true perception involves. In essence, while hallucinations occur, they do not constitute a sensory experience of the external world but are rather a cerebral production devoid of external stimuli.

2. Sensory Illusions

This perspective highlights cases like optical illusions, where a straight stick appears bent in water, suggesting that senses can be deceptive.

Binswanger's Response:

Such illusions are not errors of the senses but of judgment. The senses provide raw, uninterpreted data; it is the cognitive process that misinterprets this data. The senses, in their unerring nature, simply present the data – it is our interpretation that errs. This highlights the pivotal distinction between perception (the direct sensory data) and the interpretation thereof.

3. Sensory Adaptation

This argument stems from the phenomenon where sensory experiences differ under varying conditions, like the differing sensations in each hand when placed in lukewarm water after being in different temperatures.

Binswanger's Response:

The form of perception (feeling warm or cold) is influenced by the state of the sensory organ and the nature of the perceived object. Neither perception is erroneous; they represent different forms of the same sensory experience under varied conditions. The experience is shaped by the nature of the object, the state of the sensory organ, and the perceptive conditions, but this shaping does not equate to a failure of perception.

In summary, every alleged failure of the sensory apparatus (which is deterministic) is in fact a conceptual failure, in which an evaluation is equated with a percept. Therefore, in Descartes’ famous bent-stick-in-water scenario, the idea that the stick is “bent” is a conclusion about an attribute of the entity, not something we perceive.