LOGIC: a supposedly odourless form of pure abstracted thought

A logic is a pretentious set of linguistic rules established on the assumption that it is possible to determine valid truth statement sequences from initial truth premise statements. It contrives a set of premises, labels them as true, then constructs a fantastical edifice of abstract engineering which is then exalted as a reliable purification of reality. In the real world of chaotic uncertainties, the convenience of finding a set of true premises is never available. The logical structure and presumed certainty of the reasoning process is corrupted by improbabilities and unexpected influences.

The rules of logic are postulated to manipulate abstract entities called 'propositions'. These are usually symbolized by single letters like P, Q, R, etc, which are supposed to be the residual purified meanings of statements. Using these propositions as the raw material in the rule sequences, it is further supposed that certain conclusion propositions can be shown to be either true or false and nothing in between. Since most statements ever made about the real world are neither absolutely true, nor absolutely false, but somewhere on the probability spectrum in between, the supposed significance of logic should be viewed with a very healthy dose of suspicion. The assumptions of absolute truth or falsity of propositions are not securely founded.

The much vaunted standard logical deductions may not in fact tell us anything we did not already know. For example, the committed logician's linch-pin rule 'Modus Ponens' states that:
If (proposition P implies proposition Q ), and P is true, then Q is true.
Thus: If ( the fish is rotten implies it will smell fishy ) is true,
and the fish is rotten is true, then it will smell fishy will be true.
All of this supposedly valid argumentation relies on establishing the truth of the first implication. Unfortunately, attempting to verify its truth by catching all the fish in the world and then leaving it to become rotten would have quite undesirable consequences. Even if the stupidity of conducting such an exercise was ignored and it was discovered that all fish did smell fishy when left to become rotten, there would be no point in the logical rule. In establishing the truth of the first implication we have already established the truth of the consequent.

Logic is not often much help to a gardener. In the real world of gardening... If (it is raining) is true then (the garden will be watered) is true... can be a useful operational consideration in the overall management plan, but analysing such statements in an attempt to uncover some purified simplification of language which can be manipulated in terms of absolute truth values, is to deny the imprecisions of nature and probability. Determining whether or not it is raining is normally a simple matter of casual observation, but to try and make a black and white decision about circumstances where the degree of precipitation is variable and difficult to detect, highlights the difficulty of ever being able to make an absolutely pure true or false assignment. In the marginal situations... where all the problems usually occur... deciding whether it is raining or not will depend upon the technology available to measure all the parameters of precipitation, temperature, evaporation rate, relative humidity, etc. Two different technological set-ups might well come to two different conclusions. Ultimately... when exploring the limits of nit-picking absolutism... the best that could ever be realised would be an evaluation of the probability of truth. In very light misty conditions with average temperature and humidity, there might be a 50% probability that the statement it is raining is true. Deciding whether or not the garden will be watered is true has a similar array of existential and technological parameters to take into consideration. All of the considerations that have been mentioned above are factors that the scientific gardener would take into account within a general management program, but any 'logic'... whatever that is... is irrelevant.

Historically, it was probably assumed that the truth of the first implication premise of 'Modus Ponens' could often be arrived at 'logically' or 'synthetically'. To pragamtic gardeners however... who have to find their facts by actually digging rather than generating them in a speculative armchair... such a process is simply unrealistic.