A cursory examination of the work of Valerie Pierce might lead you to believe she has struck it lucky: some of her maxims are apparently so simple that you wonder if she's getting paid for stating the obvious.

But in Ms Pierce's business, it's thought that counts. In her view, it determines the success of individuals and the companies they work for, it engenders innovation and creativity and it is the key to good business practice.

Ms Pierce, a training consultant and a former lecturer in philosophy at Trinity College Dublin, says that as the economy becomes more knowledge-based, the need for teaching people how to think and communicate is more pressing. In the 1980s the prevailing ethos was to work as hard as possible - now people are attempting to "work smart", which requires clearer, more creative thinking.

This involves escaping from "messy perceptions, assumptions and expectations". The cardinal sin in Ms Pierce's view is to get hidebound in your own personal rationale, or to be thrown off course by the "false reasoning" of others.

She spreads this message in Clear and Critical Thinking courses in venues ranging from major banks to management workshops and to MBA programmes at several universities.

Participants are likely to hear the following sort of advice: "successful businesses depend on the intelligence of individuals at all levels to make good sense of situations and to apply this knowledge to the advantage of their organisations" or "the smart worker understands the power of communication and how to use it".

Ms Pierce contends that such has been the emphasis in the educational and business worlds on acquiring practical vocational skills, that the ability to reason clearly and impart ideas effectively is often neglected.

"Most of the time when people argue, they think up reasons that satisfy their own conclusions but if you want to influence people, you've got to think up reasons that satisfy the other people you're speaking to. That sounds easy, but in fact it's terribly difficult."

Ms Pierce admits she had difficulty at first in selling philosophy to business people. "Originally my course had the title Critical Thinking and it put people off. They thought `I'm going to learn how to be critical in the bad sense'.

"When I started to say that what I teach is Clear Thinking, people immediately said `Oh, I need some of that'. And when I branded it into sales, negotiation, influence and creativity the attitude to it was completely different. "I understand the apprehension people feel about philosophy because I come from a business family. When I started to do Philosophy in college they were absolutely amazed: `Sitting around thinking about thinking: what use is that going to be to anybody?'

"When I went on to do a PhD, I began to think that there must be some way to use this which is much more practical than just going into the nature of reality and whether we exist."

A stint as a receptionist in a public management training centre to finance her PhD studies in Bristol helped her realise how she could apply her training to the business world. "I saw that the management training courses assumed that people knew how to reason correctly and that they knew when they were being manipulated or subjected to false reasoning.

"My idea was to teach people to reason to help them to be innovative and creative, to influence, to negotiate, to run meetings and to put business plans into action."

On Ms Pierce's courses, candidates are taught not only to develop their own reasoning skills, but to appeal to other people's way of thinking. Managers are put in the shoes of employees and vice versa in role playing games. Participants are videoed, so that they can watch themselves argue a point and identify their own weaknesses. Notions that have been born out of brainstorming sessions at the start of the training sessions are later tested for their flaws and plans of action are drawn up to implement refined ideas.

Thinking clearly and effectively in business isn't just about cold logic, Ms Pierce says, it can also involve feelings if they are channelled properly.

"All logic can do is make sense of what you already know. It can't actually give you new ideas.

"Imagination is where the fun starts. You begin to see things you never saw before simply by a change in perception and then you build associations you never built before, so you get new ideas.

"Feelings are essential because without them you wouldn't even be bothered getting up in the morning, but they can also come in and absolutely destroy everything. So I split feelings into passion and emotion. Passion is the feeling attached to the product or idea or project you're selling. So if somebody criticises it, it doesn't matter because you think: This is a block to my goal. I must listen to it, try to answer it, get over the problem and I'll reach the goal. "If you're emotional, the feelings aren't attached to the product any more. They're attached to the people. If somebody says something, you become defensive because you think they're attacking your ego. That's where manipulation begins."

Ms Pierce believes philosophy and critical thinking should be taught in schools from as early an age as possible.

"In the States, critical thinking is a movement and has been introduced to most schools. I don't think anyone is too young to build up curiosity in thinking and to be taught how to manipulate their own reality better by thinking."