Transcendental Deductions and Presuppositions
I regard the paper appended below, published in Educational Philosophy and Theory in 1976, as one of my more important essays because it underlies all my other writings on philosophy, education and related matters.
An introduction seems necessary.
A transcendental deduction is a logical exercise that tries to get above itself to prove its conclusions are infallible. This is impossible. A deduction depends on the premises from which the argument starts. If the premises are false, no amount of logic can prove them true. For instance, if someone says ‘I am a politician and politicians always tell the truth’, he or she is trying to make a transcendental deduction which relies on the the premise, politicians always tell the truth. It is not very difficult to show that politicians are not always truthful. The logic is valid but we do not believe because we deny the premise
When we challenge the premises on which any logical deduction is based we are moving outside, or above the argument. We are, so to speak, attempting to transcend the deduction.
By taking such an outward or upward step we become vulnerable. If any argument is to be taken seriously it must be logical or it will be nonsense. By transcending the politician’s argument we find ourselves instantly in another. Logical arguments always do depend on premises so we face the certainty that our own premises, whatever they are, will be challenged. Another transcendental step must then to be taken and again the premises will be challenged. This could, apparently go on for ever in an infinite regression which gets nowhere.
There is, however, an end to the regression. When someone makes a statement or does something deliberately , they rely on fundamental presuppositions which anyone who uses language, or behaves purposively, also relies on. To challenge the presuppositions on which language and purposive action rely, requires the challenger to make statements and do purposive things, thus demonstrating commitment to the very principles they seek to attack.
This does not and cannot prove the final truth of any premise, but it brings all humanity, and all language- using and purposively active beings, to common ground. We cannot get beyond this. There is nowhere to go further other than to the realm of no intelligible language and no purposive action.