Having considered the importance of extending one's arguments Beyond the Facts, let us review the techniques for doing so. Our best guide, as ever, is Aristotle, whose principles of logical reasoning remain unsurpassed after more than two millennia.

Aristotle identifies two methods of drawing conclusions from facts: deductive reasoning and inductive reasoning.

Deductive Reasoning

Deductive reasoning is essentially linear: two or more facts point the way to an inescapable conclusion.

For example:

1. Supermarket customers prefer their fruit and vegetables to be fresh.
2. The supermarket receives daily deliveries of fresh fruit and vegetables.
3. All fruit and vegetables have limited "shelf-life".
4. The potential for profit from sales of fruit and vegetables reduces as the shelf-life nears its end.
5. Stock rotation must be carefully controlled if the supermarket is to satisfy the needs of customers and profit from sales of fruit and vegetables.

Premises 1-4 are deliberately organised to lead the reader towards an inevitable conclusion. It is as if the writer, having already decided that stock rotation was essential, proceeded to cite all the facts needed to prove his/her case.

However it is important to note that the validity of the conclusion depends on the correctness of the facts. For example, it may be that coconuts have such a long shelf-life that the conclusion drawn above is irrelevant with reference to coconuts.

Meanwhile a writer who is determined to prove that stock rotation is unimportant might succeed in constructing an equally persuasive, but contradictory argument by choosing different premises.

Deductive reasoning is a closed method of logic. The facts lead one's thinking in a specific direction so that ideally, from the writer's point of view, there is only one conclusion that can reasonably be drawn. Accordingly deductive reasoning is the preferred methodology for those who seek to prove "beyond reasonable doubt": prosecuting lawyers, scientific researchers, thriller-writers, etc.

Etymologically speaking, deduction is "leading out of": out of the difficult world of logical reasoning into the secure haven of established knowledge, where the work of thinking has already been done.

Inductive Reasoning

Inductive reasoning is a more open, intuitive, subjective process. It begins with a set of observations and proceeds with the formulation of hypotheses based on the observations. For example:

• Some customers prefer to buy bananas when they are still green.
• Some customers prefer to buy bananas that have an attractive, yellow skin.
• Some customers prefer to buy bananas with brown spots.
• Some customers prefer to buy bananas that are over-ripe.

There is no premeditated conclusion here, though there are many different hypotheses that might be induced. For example:

• The usual principles of stock rotation cannot be applied to bananas.
• The perfect degree of ripeness in bananas is a matter of personal preference.
• Some customers like to ripen their bananas at home.
• Customers who prefer over-ripe bananas look out for bargain prices as the stock nears the end of its shelf-life.

Clearly, the process at work here is a more creative one. Inductive ( "leading in") reasoning leads one from the (relatively) secure world of facts into the realm of the imagination. Huge leaps of thought are made possible by the fact that inductive reasoning is intuitive. Whether or not the hypotheses inspired by the observations prove to be correct, the important thing is that they open up new areas of thought and enquiry.

The illustrative observations about customer preferences fall far short of proving any of the hypotheses based on the observations, and yet the hypotheses open up new areas of research that may lead to important, stronger conclusions in due course.

It may be useful to consider the close relationship between inductive logic and subtext. Subtext is the set of subjective, unwritten conclusions that form in the reader's mind as s/he tries to assimilate the facts presented by the writer. The subconscious process of creating subtext is inductive reasoning by another name.

Focused Research

Deductive and inductive processes both serve crucial purposes in factual writing. Broadly speaking, inductive thinking helps create the project and define its scope while deductive reasoning sharpens up the persuasive, analytical thinking in the later stages of writing.

Perhaps the greatest risk for the factual writer with limited resources of time is the possibility of drowning in a sea of research. If the chosen subject is particularly well documented, one might spend a lifetime merely reading all the available source materials. This risk may be greatly mitigated by the judicious deployment of Aristotle's processes for logical thinking. For example:

• The writer begins by researching a few sources at random, with the specific aim of gaining a broad perspective on the subject.
• The writer proceeds to induce hypotheses based on the initial research, with the aims of
  - broadening the research into areas that were previously overlooked
  - and deepening his/her awareness of specific areas.
• As the intended scope of the project becomes clear, the writer becomes increasingly selective in choosing research sources, specifically excluding duplicative, irrelevant or uninformative documents.
• Far from becoming wedded to his/her hypotheses, the writer seeks to record facts that contradict the hypotheses as eagerly as s/he looks for facts that support them. "Inconvenient" facts, far from undermining the project, may inspire the induction of exciting new hypotheses.
• As hypotheses begin to "firm up" into definite conclusions, research becomes increasingly focused on the facts required to make deductive arguments.

Achieving the Right Balance between Induction and Deduction

This is not to suggest that deductive logic is the essential, or even the desirable, end point for all projects. The credibility of projects that must prove their case "beyond reasonable doubt" invariably depends on the strength of the writer's deductive reasoning. However deductive rigour is rarely possible in biography, for example, where so many facts are forever beyond reach.

Most biographies and histories inhabit a middle ground in which key conclusions are deductively drawn, enabling the writer to speak with an authority that gives credibility to his/her inductive flights of fancy.

Deductive reasoning is at its least important when the degree of creativity is greatest. For example, if the subject is poorly documented or the foreground characters are fictitious, it is inevitable that the writer's processes will be largely inductive. To the extent that inductive logic engages the imagination (by compelling readers to create subtext), it may be argued that books based on inductive logic are more interesting to read.